本文說明如何使用虛擬路由和轉發(VRF)配置使用增強型內部網關路由協定(EIGRP)的故障切換。VRF是IP路由的擴展,可提供多個路由例項。Internet服務提供商(ISP)利用此VRF為客戶建立單獨的虛擬專用網路(VPN),因為它允許路由器中存在路由表的多個例項。
EIGRP基礎知識
VRF基礎知識
本檔案中的組態是根據Cisco IOS®軟體版本12.4(15)T 13上的Cisco 3700系列路由器。
如需文件慣例的詳細資訊,請參閱思科技術提示慣例。
在本示例中,路由器R1被視為PE路由器。路由器R2和R3被視為CE路由器。路由器使用EIGRP相互通訊。如果R2失去與R1的連線(即在故障轉移的情況下),路由可以通過R3到達R1。路由器R2和R3之間具有MPLS連線。
註:使用Command Lookup Tool(僅限註冊客戶)查詢有關本文檔中使用的命令的更多資訊。
本檔案會使用以下網路設定:
本檔案會使用以下設定:
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 |
使用本節內容,確認您的組態是否正常運作。
輸出直譯器工具(僅供已註冊客戶使用)(OIT)支援某些show命令。使用OIT檢視show命令輸出的分析。
要檢驗EIGRP是否配置正確,請使用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失去與R1的連線,來自R2的路由將通過R3到達路由器R1。
發生故障切換時 |
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當R2失去與R1的連線時,嘗試在R2的Fa0/0上發出shut down命令。在路由器R2中 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的同一例項上,故障切換鏈路被啟用。 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 |
為了檢驗路由器R2是否仍然可以到達R1,請發出ping vrf 命令,以便從路由器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. |