IPv6 Multicast Address Family Support for Multiprotocol BGP

Information About IPv6 Multicast Address Family Support for Multiprotocol BGP

Multiprotocol BGP for the IPv6 Multicast Address Family

The multiprotocol BGP for the IPv6 multicast address family feature provides multicast BGP extensions for IPv6 and supports the same features and functionality as IPv4 BGP. IPv6 enhancements to multicast BGP include support for an IPv6 multicast address family and network layer reachability information (NLRI) and next hop (the next router in the path to the destination) attributes that use IPv6 addresses.

Multicast BGP is an enhanced BGP that allows the deployment of interdomain IPv6 multicast. Multiprotocol BGP carries routing information for multiple network layer protocol address families; for example, IPv6 address family and for IPv6 multicast routes. The IPv6 multicast address family contains routes used for RPF lookup by the IPv6 PIM protocol, and multicast BGP IPv6 provides for interdomain transport of the same. Users must use multiprotocol BGP for IPv6 multicast when using IPv6 multicast with BGP because the unicast BGP learned routes will not be used for IPv6 multicast.

Multicast BGP functionality is provided through a separate address family context. A subsequent address family identifier (SAFI) provides information about the type of the network layer reachability information that is carried in the attribute. Multiprotocol BGP unicast uses SAFI 1 messages, and multiprotocol BGP multicast uses SAFI 2 messages. SAFI 1 messages indicate that the routes are usable only for IP unicast, not IP multicast. Because of this functionality, BGP routes in the IPv6 unicast RIB must be ignored in the IPv6 multicast RPF lookup.

A separate BGP routing table is maintained to configure incongruent policies and topologies (for example, IPv6 unicast and multicast) by using IPv6 multicast RPF lookup. Multicast RPF lookup is very similar to the IP unicast route lookup.

No MRIB is associated with the IPv6 multicast BGP table. However, IPv6 multicast BGP operates on the unicast IPv6 RIB when needed. Multicast BGP does not insert or update routes into the IPv6 unicast RIB.

How to Implement IPv6 Multicast Address Family Support for Multiprotocol BGP

Configuring an IPv6 Peer Group to Perform Multicast BGP Routing

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router bgp as-number
  4. neighbor peer-group-name peer-group
  5. neighbor {ip-address | ipv6-address | peer-group-name } remote-as as-number
  6. address-family ipv6 [unicast | multicast ]
  7. neighbor {ip-address | peer-group-name | ipv6-address } activate
  8. neighbor {ip-address | ipv6-address } peer-group peer-group-name

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

router bgp as-number

Example:


Device(config)# router bgp 65000

Enters router configuration mode for the specified BGP routing process.

Step 4

neighbor peer-group-name peer-group

Example:


Device(config-router)# neighbor group1 peer-group

Creates a BGP peer group.

Step 5

neighbor {ip-address | ipv6-address | peer-group-name } remote-as as-number

Example:


Device(config-router)# neighbor 2001:DB8:0:CC00::1 remote-as 64600

Adds the IPv6 address of the neighbor in the specified autonomous system to the IPv6 multicast BGP neighbor table of the local router.

  • The ipv6-address argument in the neighbor remote-as command must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

Step 6

address-family ipv6 [unicast | multicast ]

Example:


Device(config-router)# address-family ipv6 multicast

Specifies the IPv6 address family, and enters address family configuration mode.

  • The unicast keyword specifies the IPv6 unicast address family. By default, the router is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified in the address-family ipv6 command.
  • The multicast keyword specifies IPv6 multicast address prefixes.

Step 7

neighbor {ip-address | peer-group-name | ipv6-address } activate

Example:


Device(config-router-af)# neighbor 2001:DB8:0:CC00::1 activate

Enables the neighbor to exchange prefixes for the specified family type with the neighbor and the local router.

  • To avoid extra configuration steps for each neighbor, use the neighbor activate command with the peer-group-name argument as an alternative in this step.

Step 8

neighbor {ip-address | ipv6-address } peer-group peer-group-name

Example:


Device(config-router-af)# neighbor 2001:DB8:0:CC00::1 peer-group group1

Assigns the IPv6 address of a BGP neighbor to a peer group.

Advertising Routes into IPv6 Multiprotocol BGP

By default, networks that are defined in router configuration mode using the network command are injected into the IPv4 unicast database. To inject a network into another database, such as the IPv6 BGP database, you must define the network using the network command in address family configuration mode for the other database, as shown for the IPv6 BGP database.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router bgp as-number
  4. address-family ipv6 [vrf vrf-name ] [unicast | multicast | vpnv6 ]
  5. network {network-number [mask network-mask ] | nsap-prefix } [route-map map-tag ]
  6. exit

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

router bgp as-number

Example:


Device(config)# router bgp 65000

Enters router configuration mode for the specified BGP routing process.

Step 4

address-family ipv6 [vrf vrf-name ] [unicast | multicast | vpnv6 ]

Example:


Device(config-router)# address-family ipv6 unicast

Specifies the IPv6 address family, and enters address family configuration mode.

  • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the address-family ipv6 command.

  • The multicast keyword specifies IPv6 multicast address prefixes.

Step 5

network {network-number [mask network-mask ] | nsap-prefix } [route-map map-tag ]

Example:


Device(config-router-af)# network 2001:DB8::/24

Advertises (injects) the specified prefix into the IPv6 BGP database (the routes must first be found in the IPv6 unicast routing table).

  • The prefix is injected into the database for the address family specified in the previous step.

  • Routes are tagged from the specified prefix as “local origin.”

  • The ipv6-prefix argument in the network command must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

  • The prefix-length argument is a decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.

Step 6

exit

Example:


Device(config-router-af)# exit

Exits address family configuration mode, and returns the device to router configuration mode.

  • Repeat this step to exit router configuration mode and return the device to global configuration mode.

Redistributing Prefixes into IPv6 Multiprotocol BGP

Redistribution is the process of redistributing, or injecting, prefixes from one routing protocol into another routing protocol. This task explains how to inject prefixes from a routing protocol into IPv6 multiprotocol BGP. Specifically, prefixes that are redistributed into IPv6 multiprotocol BGP using the redistribute router configuration command are injected into the IPv6 unicast database.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router bgp as-number
  4. address-family ipv6 [vrf vrf-name ] [unicast | multicast | vpnv6 ]
  5. redistribute bgp [process-id ] [metric metric-value ] [route-map map-name ] [source-protocol-options ]
  6. exit

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

router bgp as-number

Example:


Device(config)# router bgp 65000

Enters router configuration mode for the specified BGP routing process.

Step 4

address-family ipv6 [vrf vrf-name ] [unicast | multicast | vpnv6 ]

Example:


Device(config-router)# address-family ipv6

Specifies the IPv6 address family, and enters address family configuration mode.

  • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the address-family ipv6 command.
  • The multicast keyword specifies IPv6 multicast address prefixes.

Step 5

redistribute bgp [process-id ] [metric metric-value ] [route-map map-name ] [source-protocol-options ]

Example:


Device(config-router-af)# redistribute bgp 64500 metric 5

Redistributes IPv6 routes from one routing domain into another routing domain.

Step 6

exit

Example:


Device(config-router-af)# exit

Exits address family configuration mode, and returns the device to router configuration mode.

  • Repeat this step to exit router configuration mode and return the device to global configuration mode.

Assigning a BGP Administrative Distance


Caution

Changing the administrative distance of BGP internal routes is not recommended. One problem that can occur is the accumulation of routing table inconsistencies, which can break routing.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router bgp as-number
  4. address-family ipv6 [unicast | multicast }
  5. distance bgp external-distance internal-distance local-distance

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

router bgp as-number

Example:


Device(config)# router bgp 100

Enters router configuration mode for the specified routing process.

Step 4

address-family ipv6 [unicast | multicast }

Example:


Device(config-router)# address-family ipv6 multicast

Enters address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.

Step 5

distance bgp external-distance internal-distance local-distance

Example:


Device(config-router)# distance bgp 20 20 200

Assigns a BGP administrative distance.

Generating Translate Updates for IPv6 Multicast BGP

The multicast BGP translate-update feature generally is used in a multicast BGP-capable router that peers with a customer site that has only a BGP-capable router; the customer site has not or cannot upgrade its router to a multicast BGP-capable image. Because the customer site cannot originate multicast BGP advertisements, the router with which it peers will translate the BGP prefixes into multicast BGP prefixes, which are used for multicast-source RPF lookup.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router bgp as-number
  4. address-family ipv6 [unicast | multicast }
  5. neighbor ipv6-address translate-update ipv6 multicast [unicast ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

router bgp as-number

Example:


Device(config)# router bgp 100

Enters router configuration mode for the specified routing process.

Step 4

address-family ipv6 [unicast | multicast }

Example:


Device(config-router)# address-family ipv6 multicast

Enters address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.

Step 5

neighbor ipv6-address translate-update ipv6 multicast [unicast ]

Example:


Device(config-router)# neighbor 2001:DB8:7000::2 translate-update ipv6 multicast

Generates multiprotocol IPv6 BGP updates that correspond to unicast IPv6 updates received from a peer.

Resetting IPv6 BGP Sessions

SUMMARY STEPS

  1. enable
  2. clear bgp ipv6 {unicast | multicast } {* | autonomous-system-number | ip-address | ipv6-address | peer-group peer-group-name } [soft ] [in | out ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

clear bgp ipv6 {unicast | multicast } {* | autonomous-system-number | ip-address | ipv6-address | peer-group peer-group-name } [soft ] [in | out ]

Example:


Device# clear bgp ipv6 unicast peer-group marketing soft out

Resets IPv6 BGP sessions.

Clearing External BGP Peers

SUMMARY STEPS

  1. enable
  2. clear bgp ipv6 {unicast | multicast } external [soft ] [in | out ]
  3. clear bgp ipv6 {unicast | multicast } peer-group name

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

clear bgp ipv6 {unicast | multicast } external [soft ] [in | out ]

Example:


Device# clear bgp ipv6 unicast external soft in

Clears external IPv6 BGP peers.

Step 3

clear bgp ipv6 {unicast | multicast } peer-group name

Example:


Device# clear bgp ipv6 unicast peer-group marketing

Clears all members of an IPv6 BGP peer group.

Clearing IPv6 BGP Route Dampening Information

SUMMARY STEPS

  1. enable
  2. clear bgp ipv6 {unicast | multicast } dampening [ipv6-prefix / prefix-length ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

clear bgp ipv6 {unicast | multicast } dampening [ipv6-prefix / prefix-length ]

Example:


Device# clear bgp ipv6 unicast dampening 2001:DB8::/64

Clears IPv6 BGP route dampening information and unsuppresses the suppressed routes.

Clearing IPv6 BGP Flap Statistics

SUMMARY STEPS

  1. enable
  2. clear bgp ipv6 {unicast | multicast } flap-statistics [ipv6-prefix / prefix-length | regexp regexp | filter-list list ]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

clear bgp ipv6 {unicast | multicast } flap-statistics [ipv6-prefix / prefix-length | regexp regexp | filter-list list ]

Example:


Device# clear bgp ipv6 unicast flap-statistics filter-list 3

Clears IPv6 BGP flap statistics.

Configuration Examples for IPv6 Multicast Address Family Support for Multiprotocol BGP

Example: Configuring an IPv6 Multiprotocol BGP Peer Group

The following example configures the IPv6 multiprotocol BGP peer group named group1: 


router bgp 65000
no bgp default ipv4-unicast
neighbor group1 peer-group
neighbor 2001:DB8:0:CC00::1 remote-as 64600
address-family ipv6 unicast
 neighbor group1 activate
 neighbor 2001:DB8:0:CC00::1 peer-group group1

Example: Advertising Routes into IPv6 Multiprotocol BGP

The following example injects the IPv6 network 2001:DB8::/24 into the IPv6 unicast database of the local device. (BGP checks that a route for the network exists in the IPv6 unicast database of the local device before advertising the network.) 


router bgp 65000
 no bgp default ipv4-unicast
address-family ipv6 unicast
  network 2001:DB8::/24

Example: Redistributing Prefixes into IPv6 Multiprotocol BGP

The following example redistributes RIP routes into the IPv6 unicast database of the local device: 


router bgp 64900
no bgp default ipv4-unicast
address-family ipv6 unicast
 redistribute rip

Example: Generating Translate Updates for IPv6 Multicast BGP

The following example shows how to generate IPv6 multicast BGP updates that correspond to unicast IPv6 updates: 


router bgp 64900
 no bgp default ipv4-unicast
address-family ipv6 multicast
 neighbor 2001:DB8:7000::2 translate-update ipv6 multicast

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Command List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

—

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for IPv6 Multicast Address Family Support for Multiprotocol BGP

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1. Feature Information for IPv6 Multicast: Address Family Support for Multiprotocol BGP

Feature Name

Releases

Feature Information

IPv6 Multicast: Address Family Support for Multiprotocol BGP

Cisco IOS XE Release 2.1

This feature provides multicast BGP extensions for IPv6 and supports the same features and functionality as IPv4 BGP.