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This chapter describes how to connect the Cisco mesh access points to the network.
The wireless mesh terminates on two points on the wired network. The first location is where the RAP attaches to the wired
network, and where all bridged traffic connects to the wired network. The second location is where the CAPWAP controller connects
to the wired network; this location is where the WLAN client traffic from the mesh network connects to the wired network.
The WLAN client traffic from CAPWAP is tunneled at Layer 2, and matching WLANs should terminate on the same switch VLAN where
the controllers are collocated. The security and network configuration for each of the WLANs on the mesh depend on the security
capabilities of the network to which the controller is connected.
Figure 1. Mesh Network Traffic
Termination
Note
When an HSRP configuration is in operation on a mesh network, we recommend that the In-Out multicast mode be configured. For
more details on multicast configuration, see the Enabling Multicast on the Network (CLI) section.
For more information about designing and deploying mesh networks, see the relevant mesh
deployment guides at
This section assumes that the
controller is already active in the network and is operating in Layer 3 mode.
Note
Controller ports that the
mesh access points connect to should be untagged.
Before adding a mesh access
point to a network, do the following:
Procedure
Step 1
Add the MAC address of the
mesh access point to the controller’s MAC filter. See the Adding MAC Addresses
of Mesh Access Points to MAC Filter section.
Step 2
Define the role (RAP or MAP)
for the mesh access point. See the Defining Mesh Access Point Role section.
Step 3
Verify that Layer 3 is
configured on the controller. See the Verifying Layer 3 Configuration section.
Step 4
Configure a primary,
secondary, and tertiary controller for each mesh access point. See the
Configuring Multiple Controllers Using DHCP 43 and DHCP 60 section.
Configure a backup
controller. See the Configuring Backup Controllers section.
Step 5
Configure external
authentication of MAC addresses using an external RADIUS server. See the
Configuring External Authentication and Authorization Using a RADIUS Server.
Step 6
Configure global mesh
parameters. See the Configuring Global Mesh Parameters section.
Step 7
Configure backhaul client
access. See the Configuring Advanced Features section.
Step 8
Configure local mesh
parameters. See the Configuring Local Mesh Parameters section.
Step 9
Configure antenna parameters.
See the Configuring Antenna Gain section.
Step 10
Configure channels for serial
backhaul. This step is applicable only to serial backhaul access points. See
the Backhaul Channel Deselection on Serial Backhaul Access Point section.
Step 11
Configure the DCA channels
for the mesh access points. See the Configuring Dynamic Channel Assignment
section.
Step 12
Configure mobility groups (if desired) and assign controllers. See the Configuring Mobility Groups chapter in the Cisco Wireless Controller Configuration Guide.
Step 13
Configure Ethernet bridging
(if desired). See the Configuring Ethernet Bridging section.
Step 14
Configure advanced features
such as Ethernet VLAN tagging network, video, and voice. See the Configuring
Advanced Features section.
Adding MAC Addresses of Mesh Access Points to MAC Filter
You must enter the radio MAC address for all mesh access points that you want to use in the mesh network into the appropriate
controller. A controller only responds to discovery requests from outdoor radios that appear in its authorization list. MAC
filtering is enabled by default on the controller, so only the MAC addresses need to be configured. If the access point has
an SSC and has been added to the AP Authorization List, then the MAC address of the AP does not need to be added to the MAC
Filtering List.
You can add the mesh access point using either the GUI or the CLI.
Note
You can also download the list of mesh access point MAC addresses and push them to the controller using Cisco Prime Infrastructure.
Adding the MAC Address of the Mesh Access Point to the Controller Filter List (CLI)
To add a MAC filter entry for the mesh access point on the controller using the controller CLI, follow these steps:
Procedure
Step 1
To add the MAC address of the mesh access point to the controller filter list, enter this command:
A value of zero (0) for the wlan_id parameter specifies any WLAN, and a value of zero (0) for the interface parameter specifies none. You can enter up to 32 characters for the optional description parameter.
Step 2
To save your changes, enter this command:
save config
Defining Mesh Access Point Role
By default, AP1500s are shipped with a radio role set to MAP. You must reconfigure a mesh access point to act as a RAP.
Configuring the AP Role (CLI)
To configure the role of a mesh access point using the CLI, enter the following command:
config ap role {rootAP | meshAP} Cisco_AP
Configuring Multiple Controllers Using DHCP 43 and DHCP 60
To configure DHCP Option 43 and 60 for mesh access points in the embedded Cisco IOS DHCP server, follow these steps:
Procedure
Step 1
Enter configuration mode at the Cisco IOS CLI.
Step 2
Create the DHCP pool, including the necessary parameters such as the default router and name server. The commands used to
create a DHCP pool are as follows:
ip dhcp pool pool name
network IP Network Netmask
default-router Default router
dns-server DNS Server
where:
pool name is the name of the DHCP pool, such as AP1520
IP Network is the network IP address where the controller resides, such as 10.0.15.1
Netmask is the subnet mask, such as 255.255.255.0
Default router is the IP address of the default router, such as 10.0.0.1
DNS Server is the IP address of the DNS server, such as 10.0.10.2
Step 3
Add the option 60 line using the following syntax:
option 60 ascii “VCI string”
For the VCI string, use one of the values below. The quotation marks must be included.
For Cisco 1550 series access points, enter “Cisco AP c1550”
For Cisco 1520 series access points, enter “Cisco AP c1520”
For Cisco 1240 series access points, enter “Cisco AP c1240”
For Cisco 1130 series access points, enter “Cisco AP c1130”
Step 4
Add the option 43 line using the following syntax:
option 43 hex hex string
The hex string is assembled by concatenating the TLV values shown below:
Type + Length + Value
Type is always f1(hex). Length is the number of controller management IP addresses times 4 in hex. Value is the IP address of
the controller listed sequentially in hex.
For example, suppose that there are two controllers with management interface IP addresses 10.126.126.2 and 10.127.127.2.
The type is f1(hex). The length is 2 * 4 = 8 = 08 (hex). The IP addresses translate to 0a7e7e02 and 0a7f7f02. Assembling the
string then yields f1080a7e7e020a7f7f02.
The resulting Cisco IOS command added to the DHCP scope is listed below:
option 43 hex f1080a7e7e020a7f7f02
Configuring External Authentication and Authorization Using a RADIUS Server
External authorization and authentication of mesh access points using a RADIUS server such as Cisco ACS (4.1 and later) is
supported in release 5.2 and later releases. The RADIUS server must support the client authentication type of EAP-FAST with
certificates.
Before you employ external authentication within the mesh network, ensure that you make these changes:
The RADIUS server to be used as an AAA server must be configured on the controller.
The controller must also be configured on the RADIUS server.
Add the mesh access point configured for external authorization and authentication to the user list of the RADIUS server.
For additional details, see the Adding a Username to a RADIUS Server section.
Configure EAP-FAST on the RADIUS server and install the certificates. EAP-FAST authentication is required if mesh access points
are connected to the controller using an 802.11a interface; the external RADIUS servers need to trust Cisco Root CA 2048.
For information about installing and trusting the CA certificates, see the Configuring RADIUS Servers section.
Note
If mesh access points connect to a controller using a Fast Ethernet or Gigabit Ethernet interface, only MAC authorization
is required.
Note
This feature also supports local EAP and PSK authentication on the controller.
Configuring RADIUS Servers
To install and trust the CA certificates on the RADIUS server, follow these steps:
Procedure
Step 1
Download the CA certificates for Cisco Root CA 2048 from the following locations:
From the CiscoSecure ACS main menu, click System Configuration > ACS Certificate Setup > ACS Certification Authority Setup.
In the CA certificate file box, type the CA certificate location (path and name). For example: C:\Certs\crca2048.cer.
Click Submit.
Step 3
Configure the external RADIUS servers to trust the CA certificate as follows:
From the CiscoSecure ACS main menu, choose System Configuration > ACS Certificate Setup > Edit Certificate Trust List. The Edit Certificate Trust List appears.
Select the check box next to the Cisco Root CA 2048 (Cisco Systems) certificate name.
Click Submit.
To restart ACS, choose System Configuration > Service Control, and then click Restart.
For additional configuration details on Cisco ACS servers, see the following:
To view security statistics for mesh access points using the CLI, enter the following command:
show mesh security-statsCisco_AP
Use this command to display packet error statistics and a count of failures, timeouts, and association and authentication
successes as well as reassociations and reauthentications for the specified access point and its child.
Mesh PSK Key Provisioning
Customers with Cisco
Mesh deployment will see their Mesh Access Points (MAP) possibly moving out of
their network and joining another Mesh network when both of these Mesh
Deployments use AAA with wild card MAC filtering to allow MAPs association. As
Mesh APs security may use EAP-FAST this cannot be controlled since for EAP
security combination of MAC address and type of AP is used and there is no
controlled configuration is available. PSK option with default passphrase also
presents security risk and hijack possibility. This issue will be prominently
seen in overlapping deployments of two different SPs when the MAPs are used in
a moving vehicle (public transportations, ferry, ship and so on.). This way,
there is no restriction on MAPs to 'stick' to the SPs mesh network and MAPs can
be hijacked / getting used by another SPs network / and cannot serve intended
customers of SPs in a deployment.
The new feature
introduced in 8.2 release will enable a provision-able PSK functionality from
WLC which will help make a controlled mesh deployment and enhance MAPs security
beyond default 'cisco'
PSK used today. With this new feature the MAPs which are configured with a
custom PSK, will use this key to do their authentication with their RAPs and
WLC. A special precaution should be taken when upgrading from Controller
Software release 8.1 and below or downgrading from release 8.2. Admin needs to
understand the implications when MAP software is moving in and out of PSK
support.
If a mesh PSK mismatch occurs, we recommend that you do any one of the following three tasks to address the issue:
Delete the PSK key from the MAP as follows:
With MAP in connected state, move the MAP to EAP.
On the controller UI, navigate to the Mesh tab and delete the PSK key for the MAP.
Have a wired connection between MAP and the controller and then clear the configuration on the MAP.
This section provides instructions to configure the mesh access point to establish a connection with the controller including:
Setting the maximum range between RAP and MAP (not applicable to indoor MAPs).
Enabling a backhaul to carry client traffic.
Defining if VLAN tags are forwarded or not.
Defining the authentication mode (EAP or PSK) and method (local or external) for mesh access points including security settings
(local and external authentication).
You can configure the necessary mesh parameters using either the GUI or the CLI. All parameters are applied globally.
Configuring Global Mesh Parameters (CLI)
To configure global mesh parameters including authentication methods using the controller CLI, follow these steps:
Note
See the Configuring Global Mesh Parameters (GUI) section for descriptions, valid ranges, and default values of the parameters
used in the CLI commands.
Procedure
Step 1
To specify the maximum range (in feet) of all mesh access points in the network, enter this command:
config mesh rangefeet
To see the current range, enter the show mesh range command.
Step 2
To enable or disable IDS reports for all traffic on the backhaul, enter this command:
config mesh ids-state {enable | disable}
Step 3
To specify the rate (in Mbps) at which data is shared between access points on the backhaul interface, enter this command:
config ap bhrate {rate | auto} Cisco_AP
Step 4
To enable or disable client association on the primary backhaul (802.11a) of a mesh access point, enter these commands:
config mesh client-access {enable | disable}
config ap wlan {enable | disable} 802.11aCisco_AP
config ap wlan {add | delete} 802.11awlan_idCisco_AP
Step 5
To enable or disable VLAN transparent, enter this command:
To define a security mode for the mesh access point, enter one of the following commands:
To provide local authentication of the mesh access point by the controller, enter this command:
config mesh security {eap | psk}
To store the MAC address filter in an external RADIUS server for authentication instead of the controller (local), enter these
commands:
config macfilter mac-delimiter colon
config mesh security rad-mac-filter enable
config mesh radius-server index enable
To provide external authentication on a RADIUS server and define a local MAC filter on the controller, enter these commands:
config mesh security eap
config macfilter mac-delimiter colon
config mesh security rad-mac-filter enable
config mesh radius-serverindexenable
config mesh security force-ext-auth enable
To provide external authentication on a RADIUS server using a MAC username (such as c1520-123456) on the RADIUS server, enter
these commands:
config macfilter mac-delimiter colon
config mesh security rad-mac-filter enable
config mesh radius-serverindexenable
config mesh security force-ext-auth enable
Step 7
To save your changes, enter this command:
save config
Viewing Global Mesh Parameter Settings (CLI)
Use these commands to obtain
information on global mesh settings:
show mesh
client-access—When Backhaul Client Access is enabled, it allows
wireless client association over the backhaul radio. Generally, backhaul radio
is a 5-GHz radio for most of the mesh access points. This means that a backhaul
radio can carry both backhaul traffic and client traffic.
When Backhaul Client Access
is disabled, only backhaul traffic is sent over the backhaul radio and client
association is only over the second radio(s).
(Cisco Controller)> show mesh client-access
Backhaul with client access status: enabled
show mesh ids-state—Shows the status of the IDS
reports on the backhaul as either enabled or disabled.
show mesh
config—Displays global configuration settings.
(Cisco Controller)> show mesh config
Mesh Range....................................... 12000
Mesh Statistics update period.................... 3 minutes
Backhaul with client access status............... disabled
Background Scanning State........................ enabled
Backhaul Amsdu State............................. disabled
Mesh Security
Security Mode................................. EAP
External-Auth................................. disabled
Use MAC Filter in External AAA server......... disabled
Force External Authentication................. disabled
Mesh Alarm Criteria
Max Hop Count................................. 4
Recommended Max Children for MAP.............. 10
Recommended Max Children for RAP.............. 20
Low Link SNR.................................. 12
High Link SNR................................. 60
Max Association Number........................ 10
Association Interval.......................... 60 minutes
Parent Change Numbers......................... 3
Parent Change Interval........................ 60 minutes
Mesh Multicast Mode.............................. In-Out
Mesh Full Sector DFS............................. enabled
Mesh Ethernet Bridging VLAN Transparent Mode..... enabled
Backhaul Client Access
When Backhaul Client Access is enabled, it allows wireless client association over the backhaul radio. The backhaul radio
is a 5-GHz radio. This means that a backhaul radio can carry both backhaul traffic and client traffic.
When Backhaul Client Access
is disabled, only backhaul traffic is sent over the backhaul radio and client
association is only over the second radio(s).
Note
Backhaul Client Access is disabled by default. After this feature is enabled, all mesh access points, except subordinate AP
and its child APs in Daisy-chained deployment, reboot.
This feature is applicable to
mesh access points with two radios (1552, 1532, 1540, 1560, 1572, and Indoor
APs in Bridge mode).
Configuring Backhaul Client Access (GUI)
Procedure
Step 1
Choose Wireless > Mesh to navigate to the Mesh page.
Step 2
In the General section, check the Backhaul Client Access check box.
Step 3
Save the configuration.
What to do next
In a Flex+Bridge deployment, after you enable Backhaul Client Access globally, for the 5-GHz radios to beacon as expected,
you must enable the Install mapping on radio backhaul option for the root APs operating in Flex+Bridge mode.
For more information about enabling the Install mapping on radio backhaul option, see the "Configuring Flex+Bridge Mode (GUI)" section.
Configuring Backhaul Client Access (CLI)
Use the following command to
enable Backhaul Client Access:
All Mesh APs will be rebooted
Are you sure you want to start? (y/N)
What to do next
In a Flex+Bridge deployment, after you enable Backhaul Client Access globally, for the 5-GHz radios to beacon as expected,
you must enable the Install mapping on radio backhaul option for the root APs operating in Flex+Bridge mode.
For more information about enabling the Install mapping on radio backhaul option, see the "Configuring Flex+Bridge Mode (CLI)" section.
Configuring Local Mesh Parameters
After configuring global mesh
parameters, you must configure the following local mesh parameters for these
specific features if in use in your network:
Backhaul Data Rate.
Ethernet Bridging.
Bridge Group Name.
Workgroup Bridge.
Power and Channel Setting.
Antenna Gain Settings.
Dynamic Channel Assignment.
Configuring Wireless Backhaul Data Rate
Backhaul is used to create only the wireless connection between the access points. The backhaul interface vary between 802.11a/n/ac
rates depending upon the access point. The rate selection is important for effective use of the available RF spectrum. The
rate can also affect the throughput of client devices, and throughput is an important metric used by industry publications
to evaluate vendor devices.
Dynamic Rate Adaptation (DRA)
introduces a process to estimate optimal transmission rate for packet
transmissions. It is important to select rates correctly. If the rate is too
high, packet transmissions fail resulting in communication failure. If the rate
is too low, the available channel bandwidth is not used, resulting in inferior
products, and the potential for catastrophic network congestion and collapse.
Data rates also affect the RF
coverage and network performance. Lower data rates, for example 6 Mbps, can
extend farther from the access point than can higher data rates, for example
1300 Mbps. As a result, the data rate affects cell coverage and consequently
the number of access points required. Different data rates are achieved by
sending a more redundant signal on the wireless link, allowing data to be
easily recovered from noise. The number of symbols sent out for a packet at the
1-Mbps data rate is higher than the number of symbols used for the same packet
at 11 Mbps. Therefore, sending data at the lower bit rates takes more time than
sending the equivalent data at a higher bit rate, resulting in reduced
throughput.
In the controller release
5.2, the default data rate for the mesh 5-GHz backhaul is 24 Mbps. It remains
the same with 6.0 and 7.0 controller releases.
With the 6.0 controller
release, mesh backhaul can be configured for ‘Auto’ data rate. Once configured,
the access point picks the highest rate where the next higher rate cannot be
used because of conditions not being suitable for that rate and not because of
conditions that affect all rates. That is, once configured, each link is free
to settle down to the best possible rate for its link quality.
We recommend that you
configure the mesh backhaul to Auto.
For example, if mesh backhaul
chose 48 Mbps, then this decision is taken after ensuring that we cannot use 54
Mbps as there is not enough SNR for 54 and not because some just turned the
microwave oven on which affects all rates.
A lower bit rate might allow
a greater distance between MAPs, but there are likely to be gaps in the WLAN
client coverage, and the capacity of the backhaul network is reduced. An
increased bit rate for the backhaul network either requires more MAPs or
results in a reduced SNR between MAPs, limiting mesh reliability and
interconnection.
This figure shows the RAP
using the "auto" backhaul data rate, and it is currently using 54 Mbps with its
child MAP.
Figure 2. Bridge Rate Set to
Auto
Note
The data rate can be set on
the backhaul on a per-AP basis. It is not a global command.
Related Commands
Use these commands to obtain
information about backhaul:
Command
Description
config ap
bhrate—Configures the Cisco Bridge backhaul Tx rate.
The syntax is as follows:
(controller) > config ap bhratebackhaul-rate ap-name
Note
Preconfigured data rates for
each AP (RAP=18 Mbps, MAP1=36 Mbps) are preserved after the upgrade to 6.0 or
later software releases.??Before you upgrade to the 6.0 release, if you have
the backhaul data rate configured to any data rate, then the configuration is
preserved.
The following example shows
how to configure a backhaul rate of 36000 Kbps on a RAP:
(controller) > config ap bhrate36000 HPRAP1
show ap
bhrate—Displays the Cisco Bridge backhaul rate.
The syntax is as follows:
(controller) > show ap bhrateap-name
show mesh neigh
summary—Displays the link rate summary including the current rate
being used in backhaul
Example:
(controller) > show mesh neigh summaryHPRAP1
AP Name/Radio Channel Rate Link-Snr Flags State
--------------- -------- -------- ------- ----- -----
00:0B:85:5C:B9:20 0 auto 4 0x10e8fcb8 BEACON
00:0B:85:5F:FF:60 0 auto 4 0x10e8fcb8 BEACON DEFAULT
00:0B:85:62:1E:00 165 auto 4 0x10e8fcb8 BEACON
OO:0B:85:70:8C:A0 0 auto 1 0x10e8fcb8 BEACON
HPMAP1 165 54 40 0x36 CHILD BEACON
HJMAP2 0 auto 4 0x10e8fcb8 BEACON
Backhaul capacity and
throughput depends upon the type of the AP, that is, if it is 802.11a/n or only
802.11a, number of backhaul radios it has, and so on.
Configuring Ethernet Bridging
For security reasons, the
Ethernet port on all MAPs is disabled by default. It can be enabled only by
configuring Ethernet bridging on the root and its respective MAP.
When Ethernet bridging is enabled:
VLAN ID 0 can be configured as a native VLAN and an access VLAN, but not as non-native VLAN.
All native VLANs can be configured as a non-native VLANs also and vice-versa.
Deleting a native VLAN from the allowed VLAN list does not interfere with the native VLAN.
An old native VLAN will not be automatically added to the allowed VLAN list.
Note
Exceptions are allowed for a few protocols even though Ethernet bridging is disabled. For example, the following protocols
are allowed:
Spanning Tree Protocol (STP)
Address Resolution Protocol (ARP)
Control and Provisioning of Wireless Access Points (CAPWAP)
Bootstrap Protocol (BOOTP) packets
Enable Spanning Tree
Protocol (STP) on all connected switch ports to avoid Layer 2 looping.
Ethernet bridging has to be
enabled for two scenarios:
When you want to use the mesh nodes as bridges.
Note
You do not need to configure
VLAN tagging to use Ethernet bridging for point-to-point and
point-to-multipoint bridging deployments.
When you want to connect any
Ethernet device such as a video camera on the MAP using its Ethernet port. This
is the first step to enable VLAN tagging.
Figure 3. Point-to-Multipoint
Bridging
Configuring Native
VLAN (CLI)
Note
Prior to 8.0, the Native VLAN on the wired backhaul was set as VLAN 1.
Starting with the 8.0 release, the Native VLAN can be set.
Set the Native VLAN on the wired backhaul port using the command
config ap vlan-trunking native
vlan-id ap-name.
This applies the Native VLAN configuration to the access point.
Configuring Bridge Group Names
Bridge group names (BGNs)
control the association of mesh access points. BGNs can logically group radios
to avoid two networks on the same channel from communicating with each other.
The setting is also useful if you have more than one RAP in your network in the
same sector (area). BGN is a string of 10 characters maximum.
A BGN of
NULL VALUE
is assigned by default by manufacturing. Although not visible to you,
it allows a mesh access point to join the network prior to your assignment of
your network-specific BGN.
If you have two RAPs in your
network in the same sector (for more capacity), we recommend that you configure
the two RAPs with the same BGN, but on different channels.
When Strict Match BGN is enabled
on the mesh AP, it will scan ten times to find the matched BGN parent. After
ten scans, if the AP does not find the parent with matched BGN, it will connect
to the non-matched BGN and maintain the connection for 15 minutes. After 15
minutes the AP will again scan ten times and this cycle continues. The default
BGN functionalities remain the same when Strict Match BGN is enabled.
Configuring Bridge Group Names (CLI)
Procedure
Step 1
To set a bridge group name (BGN), enter this command:
config ap bridgegroupname setgroup-name ap-name
Note
The mesh access point reboots after a BGN configuration.
Caution
Exercise caution when you configure a BGN on a live network. Always start a BGN assignment from the farthest-most node (last
node, bottom of mesh tree) and move up toward the RAP to ensure that no mesh access points are dropped due to mixed BGNs (old
and new BGNs) within the same network.
Step 2
To verify the BGN, enter the following command:
show ap config generalap-name
Configuring Antenna Gain
You must configure the antenna gain for the mesh access point to match that of the antenna installed using the controller
GUI or controller CLI.
Configuring Antenna Gain (CLI)
Enter this command to configure the antenna gain for the 802.11a backhaul radio using the controller CLI:
where gain is entered in 0.5-dBm units (for example, 2.5 dBm =5).
Configuring Mesh Leaf Node
Access points within a mesh network operate in one of the following two ways:
Root access point (RAP)
Mesh access point (MAP)
While the RAPs have wired connections to their controller (WLC), the MAPs have wireless connections to their controller. MAPs
communicate among themselves and back to the RAP using wireless connections over the 802.11a/n/g radio backhaul. MAPs use
the Cisco Adaptive Wireless Path Protocol (AWPP) to determine the best path through the other mesh access points to the controller.
Relationships among mesh access points are as a parent, child, or neighbor.
A parent access point offers the best route back to the RAP. A parent can be either the RAP itself or another MAP.
A child access point selects the parent access point as its best route back to the RAP.
A neighbor access point is within RF range of another access point but is not selected as its parent or a child.
You can configure the MAP with lower performance to work only as a leaf node. When the mesh network is formed and converged,
the leaf node can only work as a child MAP, and cannot be selected by other MAPs as a parent MAP, so that the wireless backhaul
performance will not be downgraded.
Note
The mesh leaf node feature is supported only for the IR829 AP803 and the IW3700 Series access points.
Use the following command to configure an MAP as a leaf node:
(Cisco Controller) >config mesh block-child <ap_name> {enable|disable}
enable Enable blocking child for an MAP
disable Disable blocking child for an MAP
Use the following commands to display the details of the leaf node configuration:
(Cisco Controller) >show mesh block-child summary
AP Name AP Model BVI MAC Hop Bridge Group Name Block Child Set
---------- ------------------- ----------------- --- ----------------- -------------
AP3 AIR-CAP3602I-C-K9 4c:00:82:07:64:6b 1 mesh True
Number of Mesh APs Block Child Set............................... 1
(Cisco Controller) >show mesh block-child AP3
AP Name AP Model BVI MAC Hop Bridge Group Name Block Child Set
---------- ------------------- ----------------- --- ----------------- -------------
AP3 AIR-CAP3602I-C-K9 4c:00:82:07:64:6b 1 mesh True
Configuring Advanced Features
Configuring Ethernet VLAN Tagging
Ethernet VLAN tagging allows specific application traffic to be segmented within a wireless mesh network and then forwarded
(bridged) to a wired LAN (access mode) or bridged to another wireless mesh network (trunk mode).
A typical public safety access application that uses Ethernet VLAN tagging is the placement of video surveillance cameras
at various outdoor locations within a city. Each of these video cameras has a wired connection to a MAP. The video of all
these cameras is then streamed across the wireless backhaul to a central command station on a wired network.
Figure 4. Ethernet VLAN Tagging
Ethernet Port Notes
Ethernet VLAN tagging allows
Ethernet ports to be configured as normal, access, or trunk in both indoor and
outdoor implementations:
Note
When VLAN Transparent is
disabled, the default Ethernet port mode is normal. VLAN Transparent must be
disabled for VLAN tagging to operate and to allow configuration of Ethernet
ports. To disable VLAN Transparent, which is a global parameter, see the
Configuring Global Mesh Parameters section.
Access Mode—In this mode,
only untagged packets are accepted. All incoming packets are tagged with
user-configured VLANs called access-VLANs.
Use the access mode for
applications in which information is collected from devices connected to the
MAP, such as cameras or PCs, and then forwarded to the RAP. The RAP then
applies tags and forwards traffic to a switch on the wired network.
Trunk mode—This mode requires
the user to configure a native VLAN and an allowed VLAN list (no defaults). In
this mode, both tagged and untagged packets are accepted. Untagged packets are
accepted and are tagged with the user-specified native VLAN. Tagged packets are
accepted if they are tagged with a VLAN in the allowed VLAN list.
Use the trunk mode for
bridging applications such as forwarding traffic between two MAPs that reside
on separate buildings within a campus.
Note
The Master AP blocks the ethernet port when it receives any Bridge Protocol Data Unit
(BPDU) on any VLAN on it as it works globally (one BPDU is enough to block the port
on all VLANs). This method avoids loops, and the MAP's port does not operate until
the wired link between switches is down.
In Release 8.10 and later releases, the AP performs a loop detection and drops all
VLAN packets and BPDU so that the switch does not block the port itself.
Ethernet VLAN tagging
operates on Ethernet ports that are not used as backhauls.
Note
In the controller
releases prior to 7.2, the Root Access Point (RAP) native VLAN is forwarded out
of Mesh Access Point (MAP) Ethernet ports with Mesh Ethernet Bridging and VLAN
Transparent enabled.
In the 7.2 and 7.4
releases, the Root Access Point (RAP) native VLAN is not forwarded out of Mesh
Access Point (MAP) Ethernet ports with Mesh Ethernet Bridging and VLAN
Transparent enabled. This behavior is changed starting 7.6, where the native
VLAN is forwarded by the MAP when VLAN transparent is enabled.
This change in
behavior increases reliability and minimizes the possibility of forwarding
loops on Mesh Backhauls.
VLAN Registration
To support a VLAN on a mesh access point, all the uplink mesh access points must also support the same VLAN to allow segregation
of traffic that belongs to different VLANs. The activity by which an mesh access point communicates its requirements for a
VLAN and gets response from a parent is known as VLAN registration.
Note
VLAN registration occurs automatically. No user intervention is required.
VLAN registration is summarized below:
Whenever an Ethernet port on a mesh access point is configured with a VLAN, the port requests its parent to support that VLAN.
If the parent is able to support the request, it creates a bridge group for the VLAN and propagates the request to its parent.
This propagation continues until the RAP is reached.
When the request reaches the RAP, it checks whether it is able to support the VLAN request. If yes, the RAP creates a bridge
group and a subinterface on its uplink Ethernet interface to support the VLAN request.
If the mesh access point is not able to support the VLAN request by its child, at any point, the mesh access point replies
with a negative response. This response is propagated to downstream mesh access points until the mesh access point that requested
the VLAN is reached.
Upon receiving negative response from its parent, the requesting mesh access point defers the configuration of the VLAN. However,
the configuration is stored for future attempts. Given the dynamic nature of mesh, another parent and its uplink mesh access
points might be able to support it in the case of roaming or a CAPWAP reconnect.
Ethernet VLAN Tagging Guidelines
Follow these guidelines for Ethernet tagging:
For security reasons, the Ethernet port on a mesh access point (RAP and MAP) is disabled by default. It is enabled by configuring
Ethernet bridging on the mesh access point port.
Ethernet bridging must be enabled on all the mesh access points in the mesh network to allow Ethernet VLAN tagging to operate.
VLAN mode must be set as non-VLAN transparent (global mesh parameter). See the Configuring Global Mesh Parameters (CLI) section.
VLAN transparent is enabled by default. To set as non-VLAN transparent, you must unselect the VLAN transparent option on the
Wireless > Mesh page.
VLAN tagging can only be configured on Ethernet interfaces as follows:
On AP1500s, three of the four ports can be used as secondary Ethernet interfaces: port 0-PoE in, port 1-PoE out, and port
3- fiber. Port 2 - cable cannot be configured as a secondary Ethernet interface.
In Ethernet VLAN tagging, port 0-PoE in on the RAP is used to connect to the trunk port of the switch of the wired network.
Port 1-PoE out on the MAP is used to connect to external devices such as video cameras.
Backhaul interfaces (802.11a radios) act as primary Ethernet interfaces. Backhauls function as trunks in the network and carry
all VLAN traffic between the wireless and wired network. No configuration of primary Ethernet interfaces is required.
For indoor mesh networks, the VLAN tagging feature functions as it does for outdoor mesh networks. Any access port that is
not acting as a backhaul is secondary and can be used for VLAN tagging.
VLAN tagging cannot be implemented on RAPs because the RAPs do not have a secondary Ethernet port, and the primary port is
used as a backhaul. However, VLAN tagging can be enabled on MAPs with a single Ethernet port because the Ethernet port on
a MAP does not function as a backhaul and is therefore a secondary port.
No configuration changes are applied to any Ethernet interface acting as a backhaul. A warning displays if you attempt to
modify the backhaul’s configuration. The configuration is only applied after the interface is no longer acting as a backhaul.
No configuration is required to support VLAN tagging on any 802.11a backhaul Ethernet interface within the mesh network as
follows:
This includes the RAP uplink Ethernet port. The required configuration occurs automatically using a registration mechanism.
Any configuration changes to an 802.11a Ethernet link acting as a backhaul are ignored and a warning results. When the Ethernet
link no longer functions as a backhaul, the modified configuration is applied.
VLAN configuration is not allowed on port-02-cable modem port of AP1500s (wherever applicable). VLANs can be configured on
ports 0 (PoE-in), 1 (PoE-out), and 3 (fiber).
Up to 16 VLANs are supported on each sector. The cumulative number of VLANs supported by a RAP’s children (MAP) cannot exceed
16.
The switch port connected to the RAP must be a trunk:
The trunk port on the switch and the RAP trunk port must match.
The RAP must always connect to the native VLAN ID 1 on a switch. The RAP’s primary Ethernet interface is by default the native
VLAN of 1.
The switch port in the wired network that is attached to the RAP (port 0–PoE in) must be configured to accept tagged packets
on its trunk port. The RAP forwards all tagged packets received from the mesh network to the wired network.
No VLANs, other than those destined for the mesh sector, should be configured on the switch trunk port.
A configured VLAN on a MAP Ethernet port cannot function as a Management VLAN.
Configuration is effective only when a mesh access point is in the CAPWAP RUN state and VLAN-Transparent mode is disabled.
Whenever there roaming or a CAPWAP restart, an attempt is made to apply configuration again.
Configuring Ethernet VLAN Tagging (CLI)
To configure a MAP access port, enter this command:
config ap ethernet 1 mode access enableAP1500-MAP 50
where AP1500-MAP is the variable AP_name and 50 is the variable access_vlan ID
To configure a RAP or MAP trunk port, enter this command:
config ap ethernet 0 mode trunk enableAP1500-MAP 60
where AP1500-MAP is the variable AP_name and 60 is the variable native_vlan ID
To add a VLAN to the VLAN allowed list of the native VLAN, enter this command:
config ap ethernet 0 mode trunk addAP1500-MAP3 65
where AP1500-MAP 3 is the variable AP_name and 65 is the variable VLAN ID
To view VLAN configuration details for Ethernet interfaces on a specific mesh access point (AP Name) or all mesh access points (summary), enter this command:
show ap config ethernetap-name
To see if VLAN transparent mode is enabled or disabled, enter this command:
show mesh config
Workgroup Bridge Interoperability with Mesh Infrastructure
A workgroup bridge (WGB) is a small standalone unit that can provide a wireless infrastructure connection for Ethernet-enabled
devices. Devices that do not have a wireless client adapter to connect to the wireless network can be connected to the WGB
through the Ethernet port. The WGB is associated with the root AP through the wireless interface, which means that wired clients
get access to the wireless network.
A WGB is used to connect wired networks over a single wireless segment by informing the mesh access point of all the clients
that the WGB has on its wired segment via IAPP messages. The data packets for WGB clients contain an additional MAC address
in the 802.11 header (4 MAC headers, versus the normal 3 MAC data headers). The additional MAC in the header is the address
of the WGB itself. This additional MAC address is used to route the packet to and from the clients.
WGB association is supported on all radios of every mesh access point.
Figure 5. WGB Example
In the current architecture, while an autonomous AP functions as a workgroup bridge, only one radio interface is used for
controller connectivity, Ethernet interface for wired client connectivity, and other radio interface for wireless client connectivity.
dot11radio 1 (5 GHz) can be used to connect to a controller (using the mesh infrastructure) and Ethernet interface for wired
clients. dot11radio 0 (2.4 GHz) can be used for wireless client connectivity. Depending on the requirement, dot11radio 1 or
dot11radio 0 can be used for client association or controller connectivity.
With the 7.0 release, a wireless client on the second radio of the WGB is not dissociated by the WGB upon losing its uplink
to a wireless infrastructure or in a roaming scenario.
With two radios, one radio can be used for client access and the other radio can be used for accessing the access points.
Having two independent radios performing two independent functions provides you better control and lowers the latency. Also,
wireless clients on the second radio for the WGB do not get disassociated by the WGB when an uplink is lost or in a roaming
scenario. One radio has to be configured as a Root AP (radio role) and the second radio has to be configured as a WGB (radio
role).
Note
If one radio is configured as a WGB, then the second radio cannot be a WGB or a repeater.
The following features are not supported for use with a WGB:
Idle timeout
Web authentication—If a WGB associates to a web-authentication WLAN, the WGB is added to the exclusion list, and all of the
WGB-wired clients are deleted (web-authentication WLAN is another name for a guest WLAN).
For wired clients behind the WGB, MAC filtering, link tests, and idle timeout
Configuring Workgroup Bridges
A workgroup bridge (WGB) is
used to connect wired networks over a single wireless segment by informing the
mesh access point of all the clients that the WGB has on its wired segment via
IAPP messages. In addition to the IAPP control messages, the data packets for
WGB clients contain an extra MAC address in the 802.11 header (4 MAC headers,
versus the normal 3 MAC data headers). The extra MAC in the header is the
address of the workgroup bridge itself. This extra MAC address is used to route
the packet to and from the clients.
WGB association is supported
on both the 2.4-GHz (802.11b/g) and 5-GHz (802.11a) radios on all Cisco APs.
The supported WGB modes and
capacities are as follows:
The autonomous access points
configured as WGBs must be running Cisco IOS release 12.4.25d-JA or later.
Note
If your mesh access point has two radios, you can only configure workgroup bridge mode on one of the radios. We recommend
that you disable the second radio. Workgroup bridge mode is not supported on access points with three radios.
Client mode WGB (BSS) is
supported; however, infrastructure WGB is not supported. The client mode WGB is
not able to trunk VLAN as in an infrastructure WGB.
Multicast traffic is not
reliably transmitted to WGB because no ACKs are returned by the client.
Multicast traffic is unicast to infrastructure WGB, and ACKs are received back.
If one radio is configured as
a WGB in a Cisco IOS access point, then the second radio cannot be a WGB or a
repeater.
Mesh access points can
support up to 200 clients including wireless clients, WGB, and wired clients
behind the associated WGB.
A WGB cannot associate with
mesh access points if the WLAN is configured with WPA1 (TKIP) +WPA2 (AES), and
the corresponding WGB interface is configured with only one of these
encryptions (either WPA1 or WPA2):
Figure 6. WPA Security Settings for a
WGB
Figure 7. WPA-2 Security Settings for a
WGB
To view the status of a WGB
client, follow these steps:
Procedure
Step 1
Choose
Monitor
> Clients.
Step 2
On the client summary page,
click on the MAC address of the client or search for the client using its MAC
address.
Step 3
In the page that appears,
note that the client type is identified as a
WGB (far right).
Figure 8. Clients are Identified as a
WGB
Step 4
Click on the MAC address of
the client to view configuration details:
For a wireless client, the page seen in Monitor > Clients > Detail Page (Wireless WGB Client) is displayed.
For a wired client, the page seen in Monitor > Clients > Detail Page (Wireless WGB Client) is displayed.
We recommend using a 5-GHz radio for the uplink to Mesh AP infrastructure so you can take advantage of a strong client access
on two 5-GHz radios available on mesh access points. A 5-GHz band allows more Effective Isotropic Radiated Power (EIRP) and
is less polluted. In a two-radio WGB, configure 5-GHz radio (radio 1) mode as WGB. This radio will be used to access the mesh
infrastructure. Configure the second radio 2.4-GHz (radio 0) mode as Root for client access.
On the Autonomous access points, only one SSID can be assigned to the native VLAN. You cannot have multiple VLANs in one SSID
on the autonomous side. SSID to VLAN mapping should be unique because this is the way to segregate traffic on different VLANs.
In a unified architecture, multiple VLANs can be assigned to one WLAN (SSID).
Only one WLAN (SSID) for wireless association of the WGB to the access point infrastructure is supported. This SSID should
be configured as an infrastructure SSID and should be mapped to the native VLAN.
A dynamic interface should be created in the controller for each VLAN configured in the WGB.
A second radio (2.4-GHz) on the access point should be configured for client access. You have to use the same SSID on both
radios and map to the native VLAN. If you create a separate SSID, then it is not possible to map it to a native VLAN, due
to the unique VLAN/SSID mapping requirements. If you try to map the SSID to another VLAN, then you do not have multiple VLAN
support for wireless clients.
All Layer 2 security types are supported for the WLANs (SSIDs) for wireless client association in WGB.
This feature does not depend on the AP platform. On the controller side, both mesh and nonmesh APs are supported.
There is a limitation of 20 clients in the WGB. The 20-client limitation includes both wired and wireless clients. If the
WGB is talking to autonomous access points, then the client limit is very high.
The controller treats the wireless and wired clients behind a WGB in the same manner. Features such as MAC filtering and link
test are not supported for wireless WGB clients from the controller.
If required, you can run link tests for a WGB wireless client from an autonomous AP.
Multiple VLANs for wireless clients associated to a WGB are not supported.
Up to 16 multiple VLANs are supported for wired clients behind a WGB from the 7.0 release and later releases.
Roaming is supported for wireless and wired clients behind a WGB. The wireless clients on the other radio will not be dissociated
by the WGB when an uplink is lost or in a roaming scenario.
We recommend that you configure radio 0 (2.4 GHz) as a Root (one of the mode of operations for Autonomous AP) and radio 1
(5 GHz) as a WGB.
Configuration Example
When you configure from the CLI, the following are mandatory:
dot11 SSID (security for a WLAN can be decided based on the requirement).
Map the subinterfaces in both the radios to a single bridge group.
Note
A native VLAN is always mapped to bridge group 1 by default. For other VLANs, the bridge group number matches the VLAN number;
for example, for VLAN 46, the bridge group is 46.
Map the SSID to the radio interfaces and define the role of the radio interfaces.
In the following example, one SSID (WGBTEST) is used in both radios, and the SSID is the infrastructure SSID mapped to NATIVE
VLAN 51. All radio interfaces are mapped to bridge group -1.
You can also use the GUI of an autonomous AP for configuration. From the GUI, subinterfaces are automatically created after
the VLAN is defined.
Figure 11. SSID Configuration Page
WGB Association Check
Both the WGB association to the controller and the wireless client association to WGB can be verified by entering the show dot11 associations client command in autonomous AP.
From the controller, choose Monitor > Clients. The WGB and the wireless/wired client behind the WGB are updated and the wireless/wired client are shown as the WGB client.
A link test can also be run from the controller CLI using the following command:
(Cisco Controller) > linktest clientmac-address
Link tests from the controller are only limited to the WGB, and they cannot be run beyond the WGB from the controller to a
wired or wireless client connected to the WGB. You can run link tests for the wireless client connected to the WGB from the
WGB itself using the following command:
You can also use the following commands to know the summary of WGBs and clients associated with a Cisco lightweight access
point:
(Cisco Controller) > show wgb summary
Number of WGBs................................... 2
MAC Address
IP Address
AP Name
Status
WLAN
Auth
Protocol
Clients
00:1d:70:97:bd:e8
209.165.200.225
c1240
Assoc
2
Yes
802.11a
2
00:1e:be:27:5f:e2
209.165.200.226
c1240
Assoc
2
Yes
802.11a
5
(Cisco Controller) > show client summary
Number of Clients................................ 7
MAC Address
AP Name
Status
WLAN/Guest-Lan
Auth
Protocol
Port
Wired
00:00:24:ca:a9:b4
R14
Associated
1
Yes
N/A
29
No
00:24:c4:a0:61:3a
R14
Associated
1
Yes
802.11a
29
No
00:24:c4:a0:61:f4
R14
Associated
1
Yes
802.11a
29
No
00:24:c4:a0:61:f8
R14
Associated
1
Yes
802.11a
29
No
00:24:c4:a0:62:0a
R14
Associated
1
Yes
802.11a
29
No
00:24:c4:a0:62:42
R14
Associated
1
Yes
802.11a
29
No
00:24:c4:a0:71:d2
R14
Associated
1
Yes
802.11a
29
No
(Cisco Controller) > show wgb detail00:1e:be:27:5f:e2
Number of wired client(s): 5
MAC Address
IP Address
AP Name
Mobility
WLAN
Auth
00:16:c7:5d:b4:8f
Unknown
c1240
Local
2
No
00:21:91:f8:e9:ae
209.165.200.232
c1240
Local
2
Yes
00:21:55:04:07:b5
209.165.200.234
c1240
Local
2
Yes
00:1e:58:31:c7:4a
209.165.200.236
c1240
Local
2
Yes
00:23:04:9a:0b:12
Unknown
c1240
Local
2
No
Client Roaming
High-speed roaming of Cisco
Compatible Extension (CX), version 4 (v4) clients is supported at speeds up to
70 miles per hour in outdoor mesh deployments. An example application might be
maintaining communication with a terminal in an emergency vehicle as it moves
within a mesh public network.
Three Cisco CX v4 Layer 2
client roaming enhancements are supported:
Access point assisted
roaming—Helps clients save scanning time. When a Cisco CX v4 client associates
to an access point, it sends an information packet to the new access point
listing the characteristics of its previous access point. Roaming time
decreases when the client recognizes and uses an access point list built by
compiling all previous access points to which each client was associated and
sent (unicast) to the client immediately after association. The access point
list contains the channels, BSSIDs of neighbor access points that support the
client’s current SSID(s), and time elapsed since disassociation.
Enhanced neighbor
list—Focuses on improving a Cisco CX v4 client’s roam experience and network
edge performance, especially when servicing voice applications. The access
point provides its associated client information about its neighbors using a
neighbor-list update unicast message.
Roam reason report—Enables
Cisco CX v4 clients to report the reason why they roamed to a new access point.
It also allows network administrators to build and monitor a roam history.
Configuring a WGB for roaming—If a WGB is mobile, you can configure it to scan for a better radio connection to a parent access
point or bridge. Use the ap(config-if)#mobile station period 3 threshold 50 command to configure the workgroup bridge as a mobile station.
When you enable this setting, the WGB scans for a new parent association when it encounters a poor Received Signal Strength
Indicator (RSSI), excessive radio interference, or a high frame-loss percentage. Using these criteria, a WGB configured as
a mobile station searches for a new parent association and roams to a new parent before it loses its current association.
When the mobile station setting is disabled (the default setting), a WGB does not search for a new association until it loses
its current association.
Configuring a WGB for Limited Channel Scanning—In mobile environments such as railroads, a WGB instead of scanning all the
channels is restricted to scan only a set of limited channels to reduce the hand-off delay when the WGB roams from one access
point to another. By limiting the number of channels, the WGB scans only those required channels; the mobile WGB achieves
and maintains a continuous wireless LAN connection with fast and smooth roaming. This limited channel set is configured using
the ap(config-if)#mobile station scanset of channels.
This command invokes scanning to all or specified channels. There is no limitation on the maximum number of channels that
can be configured. The maximum number of channels that can be configured is restricted only by the number of channels that
a radio can support. When executed, the WGB scans only this limited channel set. This limited channel feature also affects
the known channel list that the WGB receives from the access point to which it is currently associated. Channels are added
to the known channel list only if they are also part of the limited channel set.
Configuration Example
The following example shows
how to configure a roaming configuration:
ap(config)#interface dot11radio1
ap(config-if)#ssid outside
ap(config-if)#packet retries16
ap(config-if)#station role workgroup-bridge
ap(config-if)#mobile station
ap(config-if)#mobile station period3threshold50
ap(config-if)#mobile station scan5745 5765
Use the
no mobile station
scan command to restore scanning to all the channels.
Troubleshooting Tips
If a wireless client is not associated with a WGB, use the following steps to troubleshoot the problem:
Verify the client configuration and ensure that the client configuration is correct.
Check the show bridge command output in autonomous AP, and confirm that the AP is reading the client MAC address from the right interface.
Confirm that the subinterfaces corresponding to specific VLANs in different interfaces are mapped to the same bridge group.
If required, clear the bridge entry using the clear bridge command (remember that this command will remove all wired and wireless clients associated in a WGB and make them associate
again).
Check the show dot11 association command output and confirm that the WGB is associated with the controller.
Ensure that the WGB has not exceeded its 20-client limitation.
In a normal scenario, if the show bridge and show dot11 association command outputs are as expected, wireless client association should be successful.
Configuring Voice Parameters in Indoor Mesh Networks
You can configure call admission control (CAC)
and QoS on the controller to manage voice and video quality on the mesh
network.
The indoor mesh access points
are 802.11e capable, and QoS is supported on the local 2.4 and 5-Ghz access
radio and the 2.4 and 5 Ghz access radio and the 2.4 and 5 Ghz backhaul radio.
CAC is supported on the backhaul and the CCXv4 clients (which provides CAC
between the mesh access point and the client)
Note
Voice is supported only on
indoor mesh networks. Voice is supported on a best-effort basis in the outdoors
in a mesh network.
Call Admission Control
Call Admission Control (CAC) enables a mesh access point to maintain controlled quality of service (QoS) when the wireless
LAN is experiencing congestion. The Wi-Fi Multimedia (WMM) protocol deployed in CCXv3 ensures sufficient QoS as long as the
wireless LAN is not congested. However, to maintain QoS under differing network loads, CAC in CCXv4 or later is required.
Two types of CAC are available for access points:
static CAC and load-based CAC. All calls on a mesh network are bandwidth-based, so mesh
access points use only static CAC.
Static CAC enables the client to specify how much
bandwidth or shared medium time is required to accept a new call. Each access point
determines whether it is capable of accommodating a particular call by looking at the
bandwidth available and compares it against the bandwidth required for the call. If
there is not enough bandwidth available to maintain the maximum allowed number of calls
with acceptable quality, the mesh access point rejects the call.
Quality of Service and Differentiated Services Code Point
Marking
Cisco supports 802.11e on the
local access and on the backhaul. Mesh access points prioritize user traffic
based on classification, and therefore all user traffic is treated on a
best-effort basis.
Resources available to users
of the mesh vary, according to the location within the mesh, and a
configuration that provides a bandwidth limitation in one point of the network
can result in an oversubscription in other parts of the network.
Similarly, limiting clients
on their percentage of RF is not suitable for mesh clients. The limiting
resource is not the client WLAN, but the resources available on the mesh
backhaul.
Similar to wired Ethernet
networks, 802.11 WLANs employ Carrier Sense Multiple Access (CSMA), but instead
of using collision detection (CD), WLANs use collision avoidance (CA), which
means that instead of each station trying to transmit as soon as the medium is
free, WLAN devices will use a collision avoidance mechanism to prevent multiple
stations from transmitting at the same time.
The collision avoidance
mechanism uses two values called CWmin and CWmax. CW stands for contention
window. The CW determines what additional amount of time an endpoint should
wait, after the interframe space (IFS), to attend to transmit a packet.
Enhanced distributed coordination function (EDCF) is a model that allows end
devices that have delay-sensitive multimedia traffic to modify their CWmin and
CWmax values to allow for statically greater (and more frequent) access to the
medium.
Cisco access points support
EDCF-like QoS. This provides up to eight queues for QoS.
These queues can be allocated
in several different ways, as follows:
Based on TOS / DiffServ
settings of packets
Based on Layer 2 or Layer 3
access lists
Based on VLAN
Based on dynamic registration
of devices (IP phones)
AP1500s, with Cisco
controllers, provide a minimal integrated services capability at the
controller, in which client streams have maximum bandwidth limits, and a more
robust differentiated services (diffServ) capability based on the IP DSCP
values and QoS WLAN overrides.
When the queue capacity has
been reached, additional frames are dropped (tail drop).
Encapsulations
Several encapsulations are
used by the mesh system. These encapsulations include CAPWAP control and data
between the controller and RAP, over the mesh backhaul, and between the mesh
access point and its client(s). The encapsulation of bridging traffic
(noncontroller traffic from a LAN) over the backhaul is the same as the
encapsulation of CAPWAP data.
There are two encapsulations
between the controller and the RAP. The first is for CAPWAP control, and the
second is for CAPWAP data. In the control instance, CAPWAP is used as a
container for control information and directives. In the instance of CAPWAP
data, the entire packet, including the Ethernet and IP headers, is sent in the
CAPWAP container.
Figure 16. Encapsulations
For the backhaul, there is
only one type of encapsulation, encapsulating mesh traffic. However, two types
of traffic are encapsulated: bridging traffic and CAPWAP control and data
traffic. Both types of traffic are encapsulated in a proprietary mesh header.
In the case of bridging
traffic, the entire packet Ethernet frame is encapsulated in the mesh header.
All backhaul frames are
treated identically, regardless of whether they are MAP to MAP, RAP to MAP, or
MAP to RAP.
Figure 17. Encapsulating Mesh
Traffic
Note
Mesh Data DTLS encryption is only supported on the wave 2 Mesh AP
such as 1540 and 1560 models only.
Queuing on the Mesh Access
Point
The mesh access point uses a
high speed CPU to process ingress frames, Ethernet, and wireless on a
first-come, first-serve basis. These frames are queued for transmission to the
appropriate output device, either Ethernet or wireless. Egress frames can be
destined for either the 802.11 client network, the 802.11 backhaul network, or
Ethernet.
AP1500s support four FIFOs
for wireless client transmissions. These FIFOs correspond to the 802.11e
platinum, gold, silver, and bronze queues, and obey the 802.11e transmission
rules for those queues. The FIFOs have a user configurable queue depth.
The backhaul (frames destined
for another outdoor mesh access point) uses four FIFOs, although user traffic
is limited to gold, silver, and bronze. The platinum queue is used exclusively
for CAPWAP control traffic and voice, and has been reworked from the standard
802.11e parameters for CWmin, CWmax, and so on, to provide more robust
transmission but higher latencies.
The 802.11e parameters for
CWmin, CWmax, and so on, for the gold queue have been reworked to provide lower
latency at the expense of slightly higher error rate and aggressiveness. The
purpose of these changes is to provide a channel that is more conducive to
video applications.
Frames that are destined for
Ethernet are queued as FIFO, up to the maximum available transmit buffer pool
(256 frames). There is support for a Layer 3 IP Differentiated Services Code
Point (DSCP), so marking of the packets is there as well.
In the controller to RAP path
for the data traffic, the outer DSCP value is set to the DSCP value of the
incoming IP frame. If the interface is in tagged mode, the controller sets the
802.1Q VLAN ID and derives the 802.1p UP (outer) from 802.1p UP incoming and
the WLAN default priority ceiling. Frames with VLAN ID 0 are not tagged.
Figure 18. Controller to RAP
Path
For CAPWAP control traffic
the IP DSCP value is set to 46, and the 802.1p user priority is set to 7. Prior
to transmission of a wireless frame over the backhaul, regardless of node
pairing (RAP/MAP) or direction, the DSCP value in the outer header is used to
determine a backhaul priority. The following sections describe the mapping
between the four backhaul queues the mesh access point uses and the DSCP values
shown in Backhaul Path QoS.
Table 1. Backhaul Path QoS
DSCP Value
Backhaul Queue
2, 4, 6, 8 to 23
Bronze
26, 32 to 63
Gold
46 to 56
Platinum
All others including 0
Silver
Note
The platinum backhaul queue
is reserved for CAPWAP control traffic, IP control traffic, and voice packets.
DHCP, DNS, and ARP requests are also transmitted at the platinum QoS level. The
mesh software inspects each frame to determine whether it is a CAPWAP control
or IP control frame in order to protect the platinum queue from use by
non-CAPWAP applications.
For a MAP to the client path,
there are two different procedures, depending on whether the client is a WMM
client or a normal client. If the client is a WMM client, the DSCP value in the
outer frame is examined, and the 802.11e priority queue is used.
Table 2. MAP to Client Path
QoS
DSCP Value
Backhaul Queue
2, 4, 6, 8 to 23
Bronze
26, 32 to 45, 47
Gold
46, 48 to 63
Platinum
All others including 0
Silver
If the client is not a WMM
client, the WLAN override (as configured at the controller) determines the
802.11e queue (bronze, gold, platinum, or silver), on which the packet is
transmitted.
For a client of a mesh access
point, there are modifications made to incoming client frames in preparation
for transmission on the mesh backhaul or Ethernet. For WMM clients, a MAP
illustrates the way in which the outer DSCP value is set from an incoming WMM
client frame.
Figure 19. MAP to RAP Path
The minimum value of the
incoming 802.11e user priority and the WLAN override priority is translated
using the information listed in
Table 3 to
determine the DSCP value of the IP frame. For example, if the incoming frame
has as its value a priority indicating the gold priority, but the WLAN is
configured for the silver priority, the minimum priority of silver is used to
determine the DSCP value.
If there is no incoming WMM
priority, the default WLAN priority is used to generate the DSCP value in the
outer header. If the frame is an originated CAPWAP control frame, the DSCP
value of 46 is placed in the outer header.
With the 5.2 code
enhancements, DSCP information is preserved in an AWPP header.
All wired client traffic is
restricted to a maximum 802.1p UP value of 5, except DHCP/DNS and ARP packets,
which go through the platinum queue.
The non-WMM wireless client
traffic gets the default QoS priority of its WLAN. The WMM wireless client
traffic may have a maximum 802.11e value of 6, but it must be below the QoS
profile configured for its WLAN. If admission control is configured, WMM
clients must use TSPEC signaling and get admitted by CAC.
The CAPWAPP data traffic
carries wireless client traffic and has the same priority and treatment as
wireless client traffic.
Now that the DSCP value is
determined, the rules described earlier for the backhaul path from the RAP to
the MAP are used to further determine the backhaul queue on which the frame is
transmitted. Frames transmitted from the RAP to the controller are not tagged.
The outer DSCP values are left intact, as they were first constructed.
Bridging Backhaul
Packets
Bridging services are
treated a little differently from regular controller-based services. There is
no outer DSCP value in bridging packets because they are not CAPWAP
encapsulated. Therefore, the DSCP value in the IP header as it was received by
the mesh access point is used to index into the table as described in the path
from the mesh access point to the mesh access point (backhaul).
Bridging Packets from and
to a LAN
Packets received from a
station on a LAN are not modified in any way. There is no override value for
the LAN priority. Therefore, the LAN must be properly secured in bridging mode.
The only protection offered to the mesh backhaul is that non-CAPWAP control
frames that map to the platinum queue are demoted to the gold queue.
Packets are transmitted to
the LAN precisely as they are received on the Ethernet ingress at entry to the
mesh.
The only way to integrate
QoS between Ethernet ports on AP1500 and 802.11a is by tagging Ethernet packets
with DSCP. AP1500s take the Ethernet packet with DSCP and places it in the
appropriate 802.11e queue.
AP1500s do not tag DSCP
itself:
On the ingress port, the
AP1500 sees a DSCP tag, encapsulates the Ethernet frame, and applies the
corresponding 802.11e priority.
On the egress port, the
AP1500 decapsulates the Ethernet frame, and places it on the wire with an
untouched DSCP field.
Ethernet devices, such as
video cameras, should have the capability to mark the bits with DSCP value to
take advantage of QoS.
Note
QoS only is relevant when
there is congestion on the network.
Guidelines For Using Voice on the Mesh Network
Follow these guidelines when
you use voice on the mesh network:
Voice is supported only on
indoor mesh networks. For outdoors, voice is supported on a best-effort basis
on a mesh infrastructure.
When voice is operating on a
mesh network, calls must not traverse more than two hops. Each sector must be
configured to require no more than two hops for voice.
RF considerations for voice
networks are as follows:
Coverage hole of 2 to 10
percent
Cell coverage overlap of 15
to 20 percent
Voice needs RSSI and SNR
values that are at least 15 dB higher than data requirements
RSSI of -67 dBm for all data
rates should be the goal for 11b/g/n and 11a/n
SNR should be 25 dB for the
data rate used by client to connect to the AP
Packet error rate (PER)
should be configured for a value of one percent or less
Channel with the lowest
utilization (CU) must be used
On the 802.11a/n/ac or 802.11b/g/n > Global parameters page, do the following:
Enable dynamic target power
control (DTPC).
Disable all data rates less
than 11 Mbps.
On the 802.11a/n/ac or 802.11b/g/n > Voice parameters page, do the following:
Load-based CAC must be
disabled.
Enable admission control (ACM) for CCXv4 or v5
clients that have WMM enabled. Otherwise, static CAC does not operate
properly.
Set the maximum RF bandwidth
to 50 percent.
Set the reserved roaming
bandwidth to 6 percent.
Enable traffic stream
metrics.
On the 802.11a/n/ac or 802.11b/g/n > EDCA parameters page, you should do the following:
Set the EDCA profile for the
interface as voice optimized.
Disable low latency MAC.
On the
QoS > Profile
page, you should do the following:
Create a voice profile and
select 802.1Q as the wired QoS protocol type.
On the
WLANs >
Edit >
QoS
page, you should do the following:
Select a QoS of platinum for
voice and gold for video on the backhaul.
Select allowed as the WMM
policy.
On the
WLANs >
Edit >
QoS
page, you should do the following:
Select CCKM for authorization
(auth) key management (mgmt) if you want to support fast roaming.
On the
x >
y page, you should do the
following:
Disable voice active
detection (VAD).
Voice Call Support in a Mesh Network
Table 1
shows the actual calls in a clean, ideal environment.
Table 4. Calls Possible with 1550
Series in 802.11a/n 802.11b/g/n Radios
1 Traffic
was bidirectional 64K voice flows. VoCoder type: G.711, PER <= 1%. Network
setup was daisy-chained with no calls traversing more than 2 hops. No external
interference.
While making a call, observe
the MOS score of the call on the 7921 phone. A MOS score between 3.5 and 4 is
acceptable.
Table 5. MOS Ratings
MOS rating
User satisfaction
> 4.3
Very satisfied
4.0
Satisfied
3.6
Some users dissatisfied
3.1
Many users dissatisfied
< 2.58
—
Enabling Mesh Multicast Containment for Video
You can use the controller CLI to configure three mesh multicast modes to manage video camera broadcasts on all mesh access
points. When enabled, these modes reduce unnecessary multicast transmissions within the mesh network and conserve backhaul
bandwidth.
Mesh multicast modes determine how bridging-enabled access points MAP and RAP send multicasts among Ethernet LANs within a
mesh network. Mesh multicast modes manage non-CAPWAP multicast traffic only. CAPWAP multicast traffic is governed by a different
mechanism.
The three mesh multicast modes are as follows:
Regular mode—Data is multicast across the entire mesh network and all its segments by bridging-enabled RAP and MAP.
In-only mode—Multicast packets received from the Ethernet by a MAP are forwarded to the RAP’s Ethernet network. No additional forwarding
occurs, which ensures that non-CAPWAP multicasts received by the RAP are not sent back to the MAP Ethernet networks within
the mesh network (their point of origin), and MAP to MAP multicasts do not occur because they are filtered out.
Note
When an HSRP configuration is in operation on a mesh network, we recommend the In-Out multicast mode be configured.
In-out mode—The RAP and MAP both multicast but in a different manner:
In-out mode is the default mode.
If multicast packets are received at a MAP over Ethernet, they are sent to the RAP; however, they are not sent to other MAP
over Ethernet, and the MAP to MAP packets are filtered out of the multicast.
If multicast packets are received at a RAP over Ethernet, they are sent to all the MAPs and their respective Ethernet networks.
When the in-out mode is in operation, it is important to properly partition your network to ensure that a multicast sent by
one RAP is not received by another RAP on the same Ethernet segment and then sent back into the network.
Note
If 802.11b clients need to receive CAPWAP multicasts, then multicast must be enabled globally on the controller as well as
on the mesh network (using the config network multicast global enable CLI command). If multicast does not need to extend to 802.11b clients beyond the mesh network, the global multicast parameter
should be disabled (using the config network multicast global disable CLI command).
Viewing the Voice Details for Mesh Networks (CLI)
Use the commands in this section to view details on voice and video calls on the mesh network:
Figure 20. Mesh Network Example
To view the total number of voice calls and the bandwidth used for voice calls on each RAP, enter this command:
To view the mesh tree topology for the network and the bandwidth utilization (used/maximum available) of voice calls and video
links for each mesh access point and radio, enter this command:
The bars (|) to the left of the AP Name field indicate the number of hops that the MAP is from its RAP.
Note
When the radio type is the same, the backhaul bandwidth utilization (bw used/max) at each hop is identical. For example, mesh
access points map1, map2, map3, and rap1 are all on the same radio backhaul (802.11a) and are using the same bandwidth (3048). All of the calls are in the same interference
domain. A call placed anywhere in that domain affects the others.
To view the mesh tree topology for the network and display the number of voice calls that are in progress by mesh access point
radio, enter this command:
show mesh cac accessAP_name
Information similar to the following appears:
AP Name Slot# Radio Calls
------------- ------- ----- -----
SB_RAP1 0 11b/g 0
1 11a 0
| SB_MAP1 0 11b/g 0
1 11a 0
|| SB_MAP2 0 11b/g 1
1 11a 0
||| SB_MAP3 0 11b/g 0
1 11a 0
Note
Each call received by a mesh access point radio causes the appropriate calls summary column to increment by one. For example,
if a call is received on the 802.11b/g radio on map2, then a value of one is added to the existing value in that radio’s calls column. In this case, the new call is the only active call on the 802.11b/g radio of map2. If one call is active when a new
call is received, the resulting value is two.
To view the mesh tree topology for the network and display the voice calls that are in progress, enter this command:
show mesh cac callpath AP_name
Information similar to the following appears:
AP Name Slot# Radio Calls
------------- ------- ----- -----
SB_RAP1 0 11b/g 0
1 11a 1
| SB_MAP1 0 11b/g 0
1 11a 1
|| SB_MAP2 0 11b/g 1
1 11a 1
||| SB_MAP3 0 11b/g 0
1 11a 0
Note
The calls column for each mesh access point radio in a call path increments by one. For example, for a call that initiates at map2
(show mesh cac call path SB_MAP2) and terminates at rap1 by way of map1, one call is added to the map2 802.11b/g and 802.11a radio calls column, one call to the map1 802.11a backhaul radio calls column, and one call to the rap1 802.11a backhaul radio calls column.
To view the mesh tree topology of the network, the voice calls that are rejected at the mesh access point radio due to insufficient
bandwidth, and the corresponding mesh access point radio where the rejection occurred, enter this command:
If a call is rejected at the map2 802.11b/g radio, its calls column increments by one.
To view the number of bronze, silver, gold, platinum, and management queues active on the specified access point, enter this
command. The peak and average length of each queue are shown as well as the overflow count.
Multicast for mesh networks cannot be enabled using the controller GUI.
IGMP Snooping
IGMP snooping delivers improved RF usage through selective multicast forwarding and optimizes packet forwarding in voice and
video applications.
A mesh access point transmits multicast packets only if a client is associated with the mesh access point that is subscribed
to the multicast group. So, when IGMP snooping is enabled, only that multicast traffic relevant to given hosts is forwarded.
To enable IGMP snooping on the controller, enter the following command:
configure network multicast igmp snooping enable
A client sends an IGMP join that travels through the mesh access point to the controller. The controller intercepts the join and creates a table entry for the client in the multicast group. The controller then proxies the IGMP join through the upstream switch or router.
You can query the status of the IGMP groups on a router by entering the following command:
router# show ip gmp groups
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
233.0.0.1 Vlan119 3w1d 00:01:52 10.1.1.130
For Layer 3 roaming, an IGMP query is sent to the client’s WLAN. The controller modifies the client’s response before forwarding
and changes the source IP address to the controller’s dynamic interface IP address.
The network hears the controller’s request for the multicast group and forwards the multicast to the new controller.
For more information about video, see the following:
Until the 7.0 release, mesh APs supported only the Manufactured Installed Certificate (MIC) to authenticate and get authenticated
by controllers to join the controller. You might have had to have your own public key infrastructure (PKI) to control CAs,
to define policies, to define validity periods, to define restrictions and usages on the certificates that are generated,
and get these certificates installed on the APs and controllers. After these customer-generated or locally significant certificates
(LSCs) are present on the APs and controllers, the devices start using these LSCs, to join, authenticate, and derive a session
key. Cisco supported normal APs from the 5.2 release and later releases and extended the support for mesh APs as well from
the 7.0 release.
Graceful fallback to MIC if APs are unable to join the controller with LSC certificates—Local APs try to join a controller
with an LSC for the number of times that are configured on the controller (the default value is 3). After these trials, the
AP deletes the LSC and tries to join a controller with an MIC.
Mesh APs try to join a controller with an LSC until its lonely timer expires and the AP reboots. The lonely timer is set for
40 minutes. After the reboot, the AP tries to join a controller with an MIC. If the AP is again not able to join a controller
with an MIC in 40 minutes, the AP reboots and then tries to join a controller with an LSC.
Note
An LSC in mesh APs is not deleted. An LSC is deleted in mesh APs only when the LSC is disabled on the controller, which causes
the APs to reboot.
Over the air provisioning of MAPs.
Guidelines for Configuration
Follow these guidelines when using LSCs for mesh APs:
This feature does not remove any preexisting certificates from an AP. It is possible for an AP to have both LSC and MIC certificates.
After an AP is provisioned with an LSC, it does not read in its MIC certificate on boot-up. A change from an LSC to an MIC
will require the AP to reboot. APs do it for a fallback if they cannot be joined with an LSC.
Provisioning an LSC on an AP does not require an AP to turn off its radios, which is vital for mesh APs, which may get provisioned
over-the-air.
Because mesh APs need a dot1x authentication, a CA and ID certificate is required to be installed on the server in the controller.
LSC provisioning can happen over Ethernet and over-the-air in case of MAPs.You have to connect the mesh AP to the controller
through Ethernet and get the LSC certificate provisioned. After the LSC becomes the default, an AP can be connected over-the-air
to the controller using the LSC certificate.
Differences Between LSCs for Mesh APs and Normal APs
CAPWAP APs use LSC for DTLS setup during a JOIN irrespective of the AP mode. Mesh APs also use the certificate for mesh security,
which involves a dot1x authentication with the controller through the parent AP. After the mesh APs are provisioned with an
LSC, they need to use the LSC for this purpose because MIC will not be read in.
Mesh APs use a statically configured dot1x profile to authenticate.
This profile is hardcoded to use "cisco" as the certificate issuer. This profile needs to be made configurable so that vendor
certificates can be used for mesh authentication (enter the config local-auth eap-profile cert-issuer vendor "prfMaP1500LlEAuth93" command).
You must enter the config mesh lsc enable/disable command to enable or disable an LSC for mesh APs. This command will cause all the mesh APs to reboot.
Note
An LSC on mesh is open for very specific Oil and Gas customers with the 7.0 release. Initially, it is a hidden feature. The
config mesh lsc enable/disable is a hidden command. Also, the config local-auth eap-profile cert-issuer vendor "prfMaP1500LlEAuth93" command is a normal command, but the "prfMaP1500LlEAuth93" profile is a hidden profile, and is not stored on the controller
and is lost after the controller reboot.
Certificate Verification Process in LSC AP
LSC-provisioned APs have both LSC and MIC certificates, but the LSC certificate will be the default one. The verification
process consists of the following two steps:
The controller sends the AP the MIC device certificate, which the AP verifies with the MIC CA.
The AP sends the LSC device certificate to the controller, which the controller verifies with the LSC CA.
Getting Certificates for LSC Feature
To configure LSC, you must first gather and install the appropriate certificates on the controller. The following steps show
how to accomplish this using Microsoft 2003 Server as the CA server.
To get the certificates for LSC, follow these steps:
Procedure
Step 1
Go to the CA server (http://<ip address of caserver/crtsrv) and login.
Step 2
Get the CA certificate as follows:
Click the Download a CA certificate link, certificate chain, or CRF.
Choose the encoding method as DER.
Click the Download CA certificate link and use the save option to download the CA certificate on to your local machine.
Step 3
To use the certificate on the controller, convert the downloaded certificate to PEM format. You can convert this in a Linux
machine using the following command:
Configure the CA certificate on the controller as follows:
Choose COMMANDS > Download File.
Choose the file type as Vendor CA Certificate from the File Type drop-down list.
Update the rest of the fields with the information of the TFTP server where the certificate is located.
Click Download.
Step 5
To install the Device certificate on the WLC, login to the CA server as mentioned in Step 1 and do the following:
Click the Request a certificate link.
Click the advanced certificate request link.
Click Create and submit a request to this CA link.
Go to the next screen and choose the Server Authentication Certificate from the Certificate Template drop-down list.
Enter a valid name, email, company, department, city, state, and country/region. (Remember it in case you want the cap method
to check the username against its database of user credentials).
Note
The e-mail is not used.
Enable Mark keys as exportable.
Click Submit.
Install the certificate on your laptop.
Step 6
Convert the device certificate obtained in the Step 5. To get the certificate, go to your internet browser options and choose
exporting to a file. Follow the options from your browser to do this. You need to remember the password that you set here.
To convert the certificate, use the following command in a Linux machine:
On the controller GUI, choose Command > Download File. Choose Vendor Device Certificate from the File Type drop-down list. Update the rest of the fields with the information of
the TFTP server where the certificate is located and the password you set in the previous step and click Download.
Step 8
Reboot the controller so that the certificates can then be used.
Step 9
You can check that the certificates were successfully installed on the controller using this command:
show local-auth certificates
Configuring a Locally Significant Certificate (CLI)
To configure a locally significant certificate (LSC), follow these steps:
Procedure
Step 1
Enable LSC and provision the LSC CA certificate in the controller.
Turn on the feature by entering the following command:
config mesh lsc {enable | disable}
Step 4
Connect the mesh AP through Ethernet and provision for an LSC certificate.
Step 5
Let the mesh AP get a certificate and join the controller using the LSC certificate.
Figure 21. Local Significant Certificate Page
Figure 22. AP Policy Configuration
LSC only MAP Authentication using wild card MAC
Information about LSC-Only MAP Authentication using wild card
MAC
The 8.0 release supports LSC only authentication
using a wild card MAC address thus disabling the MAC filter. To ensure only
authorized access points authenticate, the Cisco WLC must be able to force the
EAP with LSC authentication.
The table shows the different forms of LSC authentication.
Table 6. MAP Authentication Methods
Operation
MAC Filter
LSC Only Authentication
LSC-Only MAP Authentication enabled
disabled
enabled
LSC-Only MAP Authentication disabled
enabled
disabled
Security mode: EAP & PSK
EAP or PSK can be used
Only EAP with LSC should be used
Certificates: MIC & LSC
MIC or LSC can be used
Only EAP with LSC should be used
WLC includes the wildcard MAC address in mac filter list and
allows all APs to join the WLC. MAC authorization is disabled automatically.
EAP security mode provides valid security with LSC. During EAP-FAST, the AP
gets authenticated using LSC and gets the MSK key from WLC. Any rogue APs are
filtered out. Using these keys message handshake happens and the PTK key is
generated. The Mesh AP joins the WLC using LSC only.
The PSK security mode leads to security threat. As the MSK key
is hardcoded inside the code of the mesh AP, any AP even a rogue AP can join
the WLC. Using these keys, message handshake happens and the PTK key is
generated. The Mesh AP joins the WLC using LSC only. Wildcard with PSK must be
used only for the debugging purposes.
Configuring LSC-Only
Authentication for Mesh Access Points (GUI)
Mesh access points
must authenticate before associating with the Cisco WLC. It is not feasible to
enter every AP MAC address into every Cisco WLC filter list. Service providers
have locally significant certificates (LSC), which you can use to bypass MAC
authentication and use only LSC.
Procedure
Step 1
Choose
Security >
Certificate >
LSC .
The
Locally Significant Certificates page is
displayed.
Step 2
Select the
AP Provisioning tab.
Step 3
Select the
Enable LSC on Controller
check box.
Step 4
Select the
General tab.
Step 5
Select the
Enable
check box in the AP Provisioning
group.
Step 6
Choose
Wireless > Mesh.
The
Mesh page is displayed.
Step 7
Select or
unselect the
LSC Only
MAP Authentication check box.
Step 8
Click
Apply.
Step 9
Click
Save
Configuration.
Configuring LSC-Only
Authentication for Mesh Access Points (CLI)
Mesh access points
must authenticate before associating with the Cisco WLC. It is not feasible to
enter every AP MAC address into every Cisco WLC filter list. Service providers
have locally significant certificates (LSC), which you can use to bypass MAC
authentication and use only LSC.
Procedure
Configure LSC-only authentication for mesh access points by
entering this command:
disable—To disable an LSC on the system. Use this keyword to remove the LSC device certificate and send a message to an AP, to do
the same and disable an LSC, so that subsequent joins could be made using the MIC/SSC. The removal of the LSC CA cert on the
WLC should be done explicitly by using the CLI to accommodate any AP that has not transitioned back to the MIC/SSC.
Following is the example of the URL when using Microsoft 2003 server:
http:<ip address of CA>/sertsrv/mscep/mscep.dll
This command configures the URL to the CA server for getting the certificates. The URL contains either the domain name or
the IP address, port number (typically=80), and the CGI-PATH.
http://ipaddr:port/cgi-path
Only one CA server is allowed to be configured. The CA server has to be configured to provision an LSC.
config certificate lsc ca-server delete
This command deletes the CA server configured on the controller.
config certificate lsc ca-cert {add | delete}
This command adds or deletes the LSC CA certificate into/from the controller's CA certificate database as follows:
add—Queries the configured CA server for a CA certificate using the SSCEP getca operation, and gets into the WLC and installs
it permanently into the WLC database. If installed, this CA certificate is used to validate the incoming LSC device certificate
from the AP.
delete—Deletes the LSC CA certificate from the WLC database.
config certificate lsc subject-paramsCountry State City Orgn Dept Email
This command configures the parameters for the device certificate that will be created and installed on the controller and
the AP.
All of these strings have 64 bytes, except for the Country that has a maximum of 3 bytes. The Common Name is automatically
generated using its Ethernet MAC address. This should be given prior to the creation of the controller device certificate
request.
The above parameters are sent as an LWAPP payload to the AP, so that the AP can use these parameters to generate the certReq.
The CN is automatically generated on the AP using the current MIC/SSC "Cxxxx-MacAddr" format, where xxxx is the product number.
This command enables or disables the provisioning of the LSCs on the APs if the APs just joined using the SSC/MIC. If enabled,
all APs that join and do not have the LSC will get provisioned.
If disabled, no more automatic provisioning will be done. This command does not affect the APs, which already have LSCs in
them.
config certificate lsc ra-cert {add | delete}
We recommend this command when the CA server is a Cisco IOS CA server. The controller can use the RA to encrypt the certificate
requests and make communication more secure. RA certificates are not currently supported by other external CA servers, such
as MSFT.
add—Queries the configured CA server for an RA certificate using the SCEP operation and installs it into the controller database.
This keyword is used to get the certReq signed by the CA.
delete—Deletes the LSC RA certificate from the WLC database.
config auth-list ap-policy lsc {enable | disable}
After getting the LSC, an AP tries to join the controller. Before the AP tries to join the controller, you must mandatorily
enter this command on the controller console. By default, the config auth-list ap-policy lsc command is in the disabled state, and the APs are not allowed to join the controller using the LSC.
config auth-list ap-policy mic {enable | disable}
After getting the MIC, an AP tries to join the controller. Before the AP tries to join the controller, you must mandatorily
enter this command on the controller console. By default, the config auth-list ap-policy mic command is in the enabled state. If an AP cannot join because of the enabled state, this log message on the controller side
is displayed: LSC/MIC AP is not allowed to join.
show certificate lsc summary
This command displays the LSC certificates installed on the WLC. It would be the CA certificate, device certificate, and optionally,
an RA certificate if the RA certificate has also been installed. It also indicates if an LSC is enabled or not.
show certificate lsc ap-provision
This command displays the status of the provisioning of the AP, whether it is enabled or disabled, and whether a provision
list is present or not.
show certificate lsc ap-provision details
This command displays the list of MAC addresses present in the AP provisioning lists.
Controller GUI Security Settings
Although the settings are not
directly related to the feature, it might help you in achieving the desired
behavior with respect to APs provisioned with an LSC.
Case 1—Local MAC
Authorization and Local EAP Authentication
Add the MAC address of
RAP/MAP to the controller MAC filter list.
Check LSC Only MAP Authentication on the GUI page. This message
will be displayed:
Warning: Enabling LSC Only MAP Authentication will provision LSC Certificate into MAP
(if MAP are being provisioned for first time). Please make sure MAP is connected to WLC using Ethernet
cable to avoid security risk.
Are you sure you want to continue? (Y/N)
Deployment Guidelines
When using local authorization, the controller should be installed with the vendor's CA and device certificate.
When using an external AAA server, the controller should be installed with the vendor’s CA and device certificate.
Mesh security should be configured to use ‘vendor’ as the cert-issuer.
MAPs cannot move from an LSC to an MIC when they fall back to a backup controller.
The config mesh lsc {enable | disable} command is required to enable or disable an LSC for mesh APs. This command causes all the mesh APs to reboot.
Configuring Antenna Band Mode
Information About
Configuring Antenna Band Modes
You can configure the
antenna band modes for mesh access points as either of the following:
Dual Antenna Band Mode—The
bottom two ports, port 1 and port 2, are used for dual band 2.4-GHz and 5-GHz
dual radiating element (DRE) antennas.
Single Antenna Band Mode—The
top two ports, port 3 and port 4, are used for 5-GHz single radiating element
(SRE) antennas and the bottom two ports, port 1 and port 2, are used for
2.4-GHz SRE antennas.
Restrictions for
Configuring Antenna Band Modes
The antenna band
mode configuration is available on the Cisco Aironet 1532E and 1572EC/EAC
access point models.
Note
The Cisco
Aironet 1532I access point model has internal antenna and does not require
additional antennas.
Configuring Antenna
Band Mode (CLI)
Before you begin
Ensure that the physical antennas are correctly
configured before changing the antenna band mode. If the antenna band mode is
incorrectly configured, the mesh AP could be stranded.
Procedure
Configure
antenna band mode for a mesh AP by entering this command on the Cisco WLC CLI:
config ap
antenna-band-mode {single |
dual}
mesh-ap-name
View the status
of the antenna band mode by entering this command:
show ap config generalmesh-ap-name
Configuring Antenna Band Mode (AP CLI)
Procedure
Configure antenna band mode on the mesh AP CLI by entering this
command on the AP console:
capwap ap ant-band-mode {dual |
single}
Configuring Daisy Chaining on Cisco Aironet 1530 Series Access Points
Information About
Daisy Chaining the Cisco Aironet 1530 Series Access Points
The Cisco Aironet 1530
Series Access Points have the capability to "daisy chain" access points when
they function as mesh APs (MAPs). The "daisy chained" MAPs can either operate
the access points as a serial backhaul, allowing different channels for uplink
and downlink access thus improving backhaul bandwidth, or extend universal
access. Extending universal access allows you to connect a local mode or
FlexConnect mode Cisco AP1530 to the Ethernet port of a MAP, thus extending the
network to provide better client access.
Daisy chained access points must be cabled differently depending on how the APs are powered. If the access point is powered
using DC power, an Ethernet cable must be connected directly from the LAN port of the primary AP to the PoE in port of the
subordinate AP.
Figure 23. Daisy Chained APs using DC Power
If the access point is powered using PoE, an Ethernet cable must be connected from the LAN port of the primary AP into the
PoE Injector, which powers the subordinate AP.
Figure 24. Daisy Chained APs using PoE Injector
Daisy Chaining with the 1572
One of the key features of the 1572 access point (AP) is the ability to “daisy chain” APs while they are operating as Mesh
APs (MAPs). By “daisy chaining” MAPs, customers can either operate the APs as a serial backhaul, allowing different channels
for uplink and downlink access thus improving backhaul bandwidth, or to extend universal access. Extending universal access
allows a customer to connect a local mode or flexconnect mode 1572 AP to the Ethernet port of a MAP, thus extending the network
to provide better client access. These features are explained in detail in the following sections.
In the 8.0MR release, when the 1572 is configured as a primary AP, the following APs are supported as subordinate APs:
1572EAC
1572EC
1572IC
1552
1532E/I
3700P
Daisy-chained access points need to be cabled differently depending on the AP type of their terminating subordinate AP.
If both the primary AP and subordinate APs are 1572s, there should be an Ethernet cable from the primary AP’s Ethernet port
to the subordinate AP’s Ethernet port. Daisy chaining should be enabled on both APs.
Caution
We recommend that you connect Ethernet Bridged wired clients or Daisy-chained APs to either the Ethernet port or PoE-Out port
only. Ethernet Bridged wired clients should never be connected to PoE-in port.
If the primary AP is a 1570 and the subordinate AP is a 1532 or 3700P, the Ethernet cable connects the PoE-Out port of the
primary AP to the PoE-In port of the subordinate AP.
If the primary AP is a 1570 and the subordinate AP is a 1520 or 1550, the Ethernet cable connects the 1572's Ethernet port
to any Ethernet port on the 1552.
Serial Backhaul on the Cisco Aironet 1530/1572 Series Access Points
Daisy chaining on the Cisco Aironet Access Points can be used to provide a serial-backhaul mesh. MAP1a is the primary MAP
and has a preferred parent selected as the RAP. MAP1b is the subordinate MAP and has no preferred parent selected. MAP1b is
configured in “Bridge” AP mode with “RootAP” role. Daisy chaining is enabled for MAP1b. MAP2 has preferred parent selected
as MAP1b.
Figure 25. Daisy Chaining with Serial-Backhaul Mesh
High gain directional antenna must be used in typical serial-backhaul deployments. Additionally, preferred parent configurations
must be used to create serial-backhaul mesh networks.
The child AP selects the preferred parent based on the following conditions:
Preferred parent is the best parent.
Preferred parent has a link SNR of at least 20 dB.
Preferred parent has a link SNR in the range 12 dB and 20 dB, but no other parent is significantly better (SNR of more than
20 percent is better). For SNR that is lower than 12 dB, the configuration is ignored.
Preferred parent is not in a blocked list.
Preferred parent is not in silent mode because of dynamic frequency selection (DFS).
Preferred parent is in the same bridge group name (BGN). If the configured preferred parent is not in the same BGN and no
other parent is available, the child will associate with the parent AP using the default BGN.
Extended Universal Access
Daisy chaining on the Cisco Aironet 1530 Series Access Points can be used to extend Universal Access across a mesh network.
In this example MAP1a is the primary MAP, it is backhauled wirelessly with the RAP. MAP1b, the subordinate MAP is operating
in local/Flex-connect mode and is providing client access on both the 2.4GHz and 5GHz radio.
Figure 26. Daisy Chaining to Extend Universal Access
Important Points to Note When Configuring Daisy Chaining the Cisco Aironet 1530/1570 Series Access Points
Only Mesh Access Points (MAPs) can operate as a daisy chained APs.
The uplink daisy-chained AP is considered the primary AP; the connected AP is considered as the subordinate AP.
The connecting Ethernet cable must go from the LAN port of the primary AP to the PoE in port of the subordinate AP.
There must be a preferred parent set for each daisy-chained mesh hop; the primary MAP should have a preferred parent.
Daisy chaining must be enabled on the subordinate AP in the Bridge mode through Cisco WLC GUI or CLI or on the AP console.
Directional antennas must be used when you create a daisy chain; the antennas must be used to guide the mesh tree formation
to suit your needs.
Directional antenna must have a physical separation of 3 meters.
Ethernet bridging must be enabled on all the APs in the Bridge mode.
Configuring Daisy
Chaining (CLI)
Procedure
Configure daisy chaining by entering this command:
config ap daisy-chaining {enable |
disable}
cisco-mesh-ap
Configure the preferred parent for each serial-backhaul AP by
entering this command:
View the status of daisy chaining and the preferred parent that is
configured by entering this command:
show ap config generalcisco-ap
Configuring Daisy Chaining (AP CLI)
Procedure
Configure daisy chaining on the AP by entering this command on
the AP console:
capwap ap daisy-chaining {enable |
disable}
Configuring a
Daisy-Chain
There are a few key
components to address when configuring a daisy-chaining deployment:
Only Mesh Access
Points (MAPs) can operate as a daisy chained AP.
The uplink daisy-chained AP is considered the primary AP, and the connected AP is considered the subordinate AP.
There must be a preferred parent set for each daisy-chained mesh hop. The primary MAP should have a preferred parent.
Daisy-chaining
must be enabled on the AP, either via WLC GUI, WLC CLI, or AP CLI.
Directional
antennas should be used when creating a daisy-chain, which guides the mesh tree
formation to the customer needs.
Enabling
Daisy-Chaining using the WLC GUI
To enable Daisy-Chaining from the controller GUI, go to Wireless > Access Point > (AP_NAME) > Mesh, and then check the Daisy-Chaining check box. If the AP is used in a serial-backhaul solution, a Preferred Parent must be selected.
Note
Daisy-chaining should only be enabled on the subordinate RAP. The primary MAP should have daisy-chaining as disabled.
Enabling
Daisy-Chaining using the WLC CLI
To enable Daisy-Chaining from the WLC CLI, issue the command:
(Cisco Controller) >config ap daisy-chaining [enable/disable]
<ap_name>
The daisy chaining feature must be enabled on a per access point basis:
(Cisco Controller) >show ap config general
<ap_name>
Using Cisco WLC, you
can configure mesh convergence methods per mesh AP (MAP) or for all mesh APs.
This enables you to choose the convergence methods based on deployment without
affecting the existing convergence mechanism. The default setting is the
existing convergence mechanism.
Mesh
Convergence
Parent Loss
Detection / Keep Alive Timers
Channel Scan
/ Seek
DHCP /
CAPWAP Information
Standard
21 / 3
seconds
Scan/Seek
all 5-GHz channels
Renew/Restart CAPWAP
Fast
7 / 3
seconds
Scan/Seek
only preset channels
Maintain
DHCP and CAPWAP
Very Fast
4 / 1.5
seconds
Scan/Seek
only preset channels
Maintain
DHCP and CAPWAP
Restrictions on Mesh
Convergence
In Cisco Wave 2 APs, the convergence settings are as follows:
Table 7. Frequency to Seek Parent
Convergence Setting
Frequency to Seek Parent
Very Fast
Every 500 milliseconds
Fast
Every 750 milliseconds
Standard
Every 1 second
The frequency to seek neighbors for all convergence settings is 15 seconds.
If the AP fails to respond 8 times, the parent or the neighbor is assumed lost.
Table 8. Totaly Time Taken to Calculate Parent Loss
Convergence Setting
Total Time Taken
Very Fast
4 seconds
Fast
6 seconds
Standard
8 seconds
The neighbor (non-parent), loss time is 2 minutes.
In fast and very fast convergence, a subset channel seek is performed. The AP maintains a list of channels supported by neighboring
parents and directly seeks those channels than going for a channel scan. For standard convergence, a channel scan is performed
when the parent is lost.
Configuring Mesh
Convergence (CLI)
Procedure
Configure mesh convergence on the Cisco WLC CLI by entering this
command:
config mesh convergence {fast |
standard |
very-fast}
all
Note
The
all keyword denotes all MAP nodes.
Mesh convergence commands on the AP console:
To see the current subset list of channels:
show mesh convergence
To debug mesh convergence:
debug mesh convergence
To set convergence method at the AP:
test mesh convergence {fast |
standard |
very_fast}
Switching Between
LWAPP and Autonomous Images (AP CLI)
By default, the
Cisco AP1532 and AP1572 are set to unified mode.
Procedure
Switch the
access point from LWAPP mode to autonomous mode (aIOS) by entering this command
on the AP console:
capwap ap autonomous
Note
This command should be used only once, during initial priming of the access point. For information about switching back from
autonomous mode to LWAPP mode, see
https://supportforums.cisco.com/docs/DOC-14960.
Configuring Mesh Leaf Node
Access points within a mesh network operate in one of the following two ways:
Root access point (RAP)
Mesh access point (MAP)
While the RAPs have wired connections to their controller (WLC), the MAPs have wireless connections to their controller. MAPs
communicate among themselves and back to the RAP using wireless connections over the 802.11a/n/g radio backhaul. MAPs use
the Cisco Adaptive Wireless Path Protocol (AWPP) to determine the best path through the other mesh access points to the controller.
Relationships among mesh access points are as a parent, child, or neighbor.
A parent access point offers the best route back to the RAP. A parent can be either the RAP itself or another MAP.
A child access point selects the parent access point as its best route back to the RAP.
A neighbor access point is within RF range of another access point but is not selected as its parent or a child.
You can configure the MAP with lower performance to work only as a leaf node. When the mesh network is formed and converged,
the leaf node can only work as a child MAP, and cannot be selected by other MAPs as a parent MAP, so that the wireless backhaul
performance will not be downgraded.
Note
The mesh leaf node feature is supported only for the IR829 AP803 and the IW3700 Series access points.
Use the following command to configure an MAP as a leaf node:
(Cisco Controller) >config mesh block-child <ap_name> {enable|disable}
enable Enable blocking child for an MAP
disable Disable blocking child for an MAP
Use the following commands to display the details of the leaf node configuration:
(Cisco Controller) >show mesh block-child summary
AP Name AP Model BVI MAC Hop Bridge Group Name Block Child Set
---------- ------------------- ----------------- --- ----------------- -------------
AP3 AIR-CAP3602I-C-K9 4c:00:82:07:64:6b 1 mesh True
Number of Mesh APs Block Child Set............................... 1
(Cisco Controller) >show mesh block-child AP3
AP Name AP Model BVI MAC Hop Bridge Group Name Block Child Set
---------- ------------------- ----------------- --- ----------------- -------------
AP3 AIR-CAP3602I-C-K9 4c:00:82:07:64:6b 1 mesh True
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