本文档介绍如何使用虚拟路由和转发(VRF)使用增强型内部网关路由协议(EIGRP)配置故障切换。VRF是IP路由的扩展,提供多个路由实例。Internet服务提供商(ISP)利用此VRF为客户创建单独的虚拟专用网络(VPN),因为它允许路由表中存在多个实例。
EIGRP 的基础知识
VRF的基本知识
本文档中的配置基于Cisco IOS®软件版本12.4(15)T 13上的Cisco 3700系列路由器。
有关文档规则的详细信息,请参阅 Cisco 技术提示规则。
在本例中,路由器R1被视为PE路由器。路由器R2和R3被视为CE路由器。路由器使用EIGRP相互通信。如果R2与R1失去连接(即,在故障转移情况下),路由可以通过R3到达R1。路由器R2和R3之间有MPLS连接。
注意:使用命令查找工具(仅限注册客户)可查找有关本文档中使用的命令的详细信息。
本文档使用以下网络设置:
本文档使用以下配置:
路由器 R1 |
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! version 12.4 ! hostname R1 ! ip cef ! ! interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface FastEthernet0/0 ip address 192.168.1.2 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 ip address 57.35.169.2 255.255.255.0 duplex auto speed auto ! router eigrp 220 network 2.2.2.2 0.0.0.0 network 57.35.169.2 0.0.0.0 network 192.168.1.0 no auto-summary !--- Configured EIGRP and advertised the networks. ! end |
路由器 R2 |
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! version 12.4 ! hostname R2 ! ip cef ! ip vrf A !--- Configures VRF routing table! rd 1.1.1.1:111 !---Configuring a route distinguisher RD creates routing and forwarding table for a VRF. The RD can be used in either of these formats: - 16-bit AS number: Your 32-bit number (for example, 1:100) - 32-bit IP address: Your 16-bit number (In our case, 1.1.1.1:111) route-target export 1.1.1.1:111 route-target import 1.1.1.1:111 !--- Creates a list of import and/or export route target communities for the specified VRF. ! ip vrf B rd 2.2.2.2:222 import ipv4 unicast map vrfA-to-vrfB !--- Associates the specified route map with the VRF. route-target export 2.2.2.2:222 route-target import 2.2.2.2:222 ! mpls label protocol ldp ! interface Loopback1 ip vrf forwarding B !--- Associates a VRF instance with an interface. ip address 172.16.2.1 255.255.255.255 ! interface FastEthernet0/0 ip vrf forwarding A ip address 192.168.1.1 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 ip vrf forwarding A ip address 10.0.0.1 255.255.255.0 duplex auto speed auto mpls ip ! interface FastEthernet1/0 ip vrf forwarding B ip address 203.197.194.1 255.255.255.0 duplex auto speed auto ! router eigrp 1 no auto-summary ! address-family ipv4 vrf B !--- Enter address family configuration mode for configuring EIGRP routing sessions. network 172.16.2.0 0.0.0.255 network 203.197.194.0 no auto-summary autonomous-system 330 !--- Defines the autonomous system number for this specific instance of EIGRP. exit-address-family ! address-family ipv4 vrf A network 10.0.0.1 0.0.0.0 network 192.168.1.0 no auto-summary autonomous-system 220 exit-address-family ! access-list 99 permit 172.16.1.0 0.0.0.255 access-list 99 permit 192.168.1.0 0.0.0.255 access-list 101 permit udp host 192.168.1.1 eq bootps host 1.1.1.1 eq bootps !--- Create access list in order to permit the host addresses. ! route-map vrfA-to-vrfB permit 10 match ip address 99 !--- Created a route map and distributed the routes permitted by access list 99. ! end |
路由器 R3 |
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! version 12.4 ! hostname R3 ! ip cef ! ! ! ! ip vrf A rd 1.1.1.1:111 ! mpls label protocol ldp ! interface Loopback1 ip address 1.1.1.1 255.255.255.255 ! interface FastEthernet0/0 ip vrf forwarding A ip address 10.0.0.2 255.255.255.0 duplex auto speed auto mpls ip ! interface FastEthernet0/1 ip vrf forwarding A ip address 57.35.169.1 255.255.255.0 duplex auto speed auto ! interface FastEthernet1/0 ip address 203.197.194.2 255.255.255.0 duplex auto speed auto ! router eigrp 330 network 1.1.1.1 0.0.0.0 network 10.0.0.2 0.0.0.0 network 57.35.169.1 0.0.0.0 network 203.197.194.0 no auto-summary ! address-family ipv4 vrf A network 10.0.0.2 0.0.0.0 network 57.35.169.1 0.0.0.0 no auto-summary autonomous-system 220 exit-address-family ! end |
使用本部分可确认配置能否正常运行。
命令输出解释程序(仅限注册用户)(OIT) 支持某些 show 命令。使用 OIT 可查看对 show 命令输出的分析。
要检验EIGRP是否配置正确,请使用show ip route vrf命令。
show ip route vrf |
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在路由器 R2 中 R2#show ip route vrf A Routing Table: A Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 I - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 2.0.0.0/32 is subnetted, 1 subnets D 2.2.2.2 [90/409600] via 192.168.1.2, 00:15:47, FastEthernet0/0 57.0.0.0/24 is subnetted, 1 subnets D 57.35.169.0 [90/307200] via 192.168.1.2, 00:15:47, FastEthernet0/0 [90/307200] via 10.0.0.2, 00:15:47, FastEthernet0/1 10.0.0.0/24 is subnetted, 1 subnets C 10.0.0.0 is directly connected, FastEthernet0/1 C 192.168.1.0/24 is directly connected, FastEthernet0/0在路由器 R3 中 R3#show ip route vrf A Routing Table: A Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 I - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 2.0.0.0/32 is subnetted, 1 subnets D 2.2.2.2 [90/409600] via 57.35.169.2, 00:16:59, FastEthernet0/1 57.0.0.0/24 is subnetted, 1 subnets C 57.35.169.0 is directly connected, FastEthernet0/1 10.0.0.0/24 is subnetted, 1 subnets C 10.0.0.0 is directly connected, FastEthernet0/0 D 192.168.1.0/24 [90/307200] via 57.35.169.2, 00:17:02, FastEthernet0/1 [90/307200] via 10.0.0.1, 00:17:02, FastEthernet0/0 !--- Displays the routing table associated with VRF instance A. |
如果R2与R1失去连接,则从R2到路由器R1的路由将通过R3到达。
在故障切换时 |
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当R2失去与R1的连接时,尝试在R2的Fa0/0上关闭。在路由器R2 R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#int fa0/0 R2(config-if)#shut down R2(config-if)# *Mar 1 00:01:01.539: %TDP-5-INFO: VRF A: TDP ID removed *Mar 1 00:01:01.675: %LDP-5-NBRCHG: LDP Neighbor (vrf A) 57.35.169.1:0 (1) is DOWN (LDP Router ID changed) *Mar 1 00:01:01.679: %DUAL-5-NBRCHANGE: IP-EIGRP(1) 220: Neighbor 192.168.1.2 (FastEthernet0/0) is down: interface down R2(config-if)# *Mar 1 00:01:03.519: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down *Mar 1 00:01:04.519: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down在路由器R3的同一实例中,故障切换链路激活。 R3# *Mar 1 00:00:52.527: %LDP-5-NBRCHG: LDP Neighbor (vrf A) 192.168.1.1:0 (1) is DOWN (TCP connection closed by peer) R3# *Mar 1 00:00:59.591: %LDP-5-NBRCHG: LDP Neighbor (vrf A) 10.0.0.1:0 (1) is UP |
要检验路由器R2是否仍能到达R1,请发出ping vrf命令,以便从路由器R2 ping R1。
ping |
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在路由器 R2 中 R2#ping vrf A 192.168.1.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/51/96 ms !--- R2 can still reach R1 through R3. |