简介
本文档介绍如何在运行NX-OS模式的Nexus交换机上使用MSDP配置任意播RP。
先决条件
要求
建议您了解以下主题:
使用的组件
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您的网络处于活动状态,请确保您了解所有命令的潜在影响。
本文档中的信息基于NXOS版本9.3.9的Cisco Nexus 9000。
背景信息
虽然任播RP协议更常用于在同一个路由域中的两个或多个PIM路由器之间共享RP的角色,但也可以使用MSDP。
配置
网络图
注意:在上图中,蓝色链路标记为第2层接口,红色链路标记为第3层接口。
在MSDP之前配置单播和组播
在配置MSDP之前,必须在所有第3层Nexus交换机(包括RP)上配置单播和组播。在本示例中,所有第3层接口上都配置了EIGRP,并且从源到接收方的ICMP ping操作成功。
默认情况下,IGMP在第3层接口上配置。但是,您必须在第3层接口上启用PIM,并静态配置您计划在RP-1和RP-2上使用的rp地址:
FHR-1:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface Vlan87
ip pim sparse-mode
interface Ethernet1/7
ip pim sparse-mode
interface Ethernet1/9
ip pim sparse-mode
FHR-2:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface Vlan87
ip pim sparse-mode
interface Ethernet1/7
ip pim sparse-mode
interface Ethernet1/9
ip pim sparse-mode
RP-1:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface loopback0
ip pim sparse-mode
interface Ethernet1/53
ip pim sparse-mode
interface Ethernet1/54
ip pim sparse-mode
RP-2:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface loopback0
ip pim sparse-mode
interface Ethernet1/53
ip pim sparse-mode
interface Ethernet1/54
ip pim sparse-mode
LHR-1:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface Vlan5
ip pim sparse-mode
interface Ethernet1/53
ip pim sparse-mode
interface Ethernet1/54
ip pim sparse-mode
LHR-2:
feature pim
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
interface Vlan5
ip pim sparse-mode
interface Ethernet1/53
ip pim sparse-mode
interface Ethernet1/54
ip pim sparse-mode
在网络中的所有RP上配置MSDP对等
作为任播RP集成员的每个Nexus交换机都必须配置为与所有其他Nexus交换机对等。在本示例中,RP-1和RP-2均配置为对等体:
RP-1:
feature msdp
ip msdp originator-id loopback1
ip msdp peer 10.1.1.3 connect-source loopback1
ip msdp mesh-group 10.1.1.3 rp-mesh
interface loopback0
description Anycast RP Address
ip address 10.1.1.1/32
ip router eigrp 1
ip pim sparse-mode
interface loopback1
description MSDP Originator ID
ip address 10.1.1.2/32
ip router eigrp 1
RP-2:
feature msdp
ip msdp originator-id loopback1
ip msdp peer 10.1.1.2 connect-source loopback1
ip msdp mesh-group 10.1.1.2 rp-mesh
interface loopback0
description Anycast RP Address
ip address 10.1.1.1/32
ip router eigrp 1
ip pim sparse-mode
interface loopback1
description MSDP Originator ID
ip address 10.1.1.3/32
ip router eigrp 1
注意:在本示例中,接口loopback1用于MSDP对等而不是PIM。因此,不需要在接口loopback1上配置ip pim sparse-mode。也就是说,在接口loopback1上启用PIM稀疏模式没有危害。
验证
当您看到Connection State is Established时,MSDP对等配置正确。您可以看到(S,G)s Received increase:
RP-1# show ip msdp summary
MSDP Peer Status Summary for VRF "default"
Local ASN: 0, originator-id: 10.1.1.2
Number of configured peers: 1
Number of established peers: 1
Number of shutdown peers: 0
Peer Peer Connection Uptime/ Last msg (S,G)s
Address ASN State Downtime Received Received
10.1.1.3 0 Established 01:33:54 never 1
注意:如果网络中没有组播,则(S,G)s Received的计数器保持为0。
故障排除
MSDP对等停滞在侦听状态
show ip msdp summary命令表明连接状态处于侦听状态:
RP-1# show ip msdp summary
MSDP Peer Status Summary for VRF "default"
Local ASN: 0, originator-id: 10.1.1.2
Number of configured peers: 1
Number of established peers: 0
Number of shutdown peers: 0
Peer Peer Connection Uptime/ Last msg (S,G)s
Address ASN State Downtime Received Received
10.1.1.3 0 Listening 00:03:27 never 0
此问题的可能原因如下:
- MSDP配置不正确。
- 连接故障导致MSDP对等无法相互连接。
在本示例中,假设配置正确,则可以使用ethanalyzer来排除10.1.1.2和10.1.1.3之间的潜在数据包丢失故障。
注意:请观看如何在Nexus系列交换机上执行Ethanalyzer捕获,以了解有关Ethanalyzer的详细信息。
组播(S、G)s未共享
如果Connection State为Established但(S,G)s Received未增加,则可能是MSDP未正确配置。此行为最可能的原因是(S,G)由于检测到重复的rp地址而被丢弃:
RP-1# show ip msdp event-history events | i looping
2023 Sep 22 12:13:15.106735 msdp [26860]: : Possible looping SA or duplicate RP address exists, RP 10.1.1.1, entry count: 1, length 20, message discarded
2023 Sep 22 12:10:10.314695 msdp [26860]: : Possible looping SA or duplicate RP address exists, RP 10.1.1.1, entry count: 1, length 20, message discarded
2023 Sep 22 12:09:08.352690 msdp [26860]: : Possible looping SA or duplicate RP address exists, RP 10.1.1.1, entry count: 1, length 20, message discarded
2023 Sep 22 12:08:06.688953 msdp [26860]: : Possible looping SA or duplicate RP address exists, RP 10.1.1.1, entry count: 1, length 20, message discarded
2023 Sep 22 12:07:04.403736 msdp [26860]: : Possible looping SA or duplicate RP address exists, RP 10.1.1.1, entry count: 1, length 20, message discarded
默认情况下,Nexus交换机配置为使用rp-address作为发起方ID。但是,这会导致每个MSDP对等使用相同的发起方ID,从而导致(S,G)被丢弃。
在本示例中,如果未配置发起方ID,则当来自环回接口0的rp地址10.1.1.1必须是任播RP的唯一IP才能工作时,该地址将用作发起方ID:
RP-1:
feature msdp
ip msdp peer 10.1.1.3 connect-source loopback1
ip msdp mesh-group 10.1.1.3 rp-mesh
interface loopback0
description Anycast RP Address
ip address 10.1.1.1/32
ip router eigrp 1
ip pim sparse-mode
interface loopback1
description MSDP Originator ID
ip address 10.1.1.2/32
ip router eigrp 1
RP-2:
feature msdp
ip msdp peer 10.1.1.2 connect-source loopback1
ip msdp mesh-group 10.1.1.2 rp-mesh
interface loopback0
description Anycast RP Address
ip address 10.1.1.1/32
ip router eigrp 1
ip pim sparse-mode
interface loopback1
description MSDP Originator ID
ip address 10.1.1.3/32
ip router eigrp
originator-id在MSDP summary show命令中确认:
RP-1# show ip msdp summary
MSDP Peer Status Summary for VRF "default"
Local ASN: 0, originator-id: 10.1.1.1 <--- rp-address from loopback0 is used for the originator-id
Number of configured peers: 1
Number of established peers: 0
Number of shutdown peers: 0
Peer Peer Connection Uptime/ Last msg (S,G)s
Address ASN State Downtime Received Received
10.1.1.3 0 Established 01:33:54 never 0
RP-2# show ip msdp summary
MSDP Peer Status Summary for VRF "default"
Local ASN: 0, originator-id: 10.1.1.1 <--- rp-address from loopback0 is used for the originator-id
Number of configured peers: 1
Number of established peers: 0
Number of shutdown peers: 0
Peer Peer Connection Uptime/ Last msg (S,G)s
Address ASN State Downtime Received Received
10.1.1.2 0 Established 01:33:54 never 0
注意:如果MSDP用于在rp-address通常不同的BGP自治系统(AS)之间对等,则发起方ID可以保留为默认值。但是,如果MSDP用于任意播RP,则发起方ID在每个MSDP对等上必须是唯一的。
要解决此问题,必须在两个MSDP对等体上配置ip msdp originator-id loopback1,以确保使用唯一的发起方ID。
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