Este documento descreve como configurar failover com EIGRP (Enhanced Interior Gateway Routing Protocol) usando VRF (Virtual Routing and Forwarding). O VRF é uma extensão do roteamento IP que fornece várias instâncias de roteamento. Os provedores de serviços de Internet (ISPs) aproveitam esse VRF para criar redes virtuais privadas (VPNs) separadas para os clientes, pois permite que várias instâncias da tabela de roteamento existam em um roteador.
Conhecimento básico do EIGRP
Conhecimento básico de VRF
As configurações neste documento são baseadas no Cisco 3700 Series Router no Cisco IOS® Software Release 12.4 (15)T 13.
Consulte as Convenções de Dicas Técnicas da Cisco para obter mais informações sobre convenções de documentos.
Neste exemplo, o roteador R1 é considerado um roteador PE. Os roteadores R2 e R3 são considerados roteadores CE. Os roteadores usam o EIGRP para se comunicar entre si. Se R2 perder conectividade com R1 (ou seja, em caso de failover), as rotas podem alcançar R1 através de R3. Os roteadores R2 e R3 têm uma conexão MPLS entre eles.
Nota:Use a Command Lookup Tool (somente clientes registrados) para obter mais informações sobre os comandos usados neste documento.
Este documento utiliza a seguinte configuração de rede:
Este documento utiliza as seguintes configurações:
Roteador 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 |
Roteador 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 |
Roteador 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 |
Use esta seção para confirmar se a sua configuração funciona corretamente.
A Output Interpreter Tool ( somente clientes registrados) (OIT) oferece suporte a determinados comandos show. Use a OIT para exibir uma análise da saída do comando show.
Para verificar se o EIGRP está configurado corretamente, use o comando show ip route vrf.
show ip route vrf |
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No roteador R2 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, FastEthernet0/0No roteador R3 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. |
Se R2 perder a conectividade com R1, as rotas de R2 chegarão ao roteador R1 até R3.
Em caso de failover |
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Quando R2 perder a conectividade com R1, tente emitir shutdown na Fa0/0 de R2. No roteador 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 downNa mesma instância do roteador R3, o link de failover é ativado. 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 |
Para verificar se o roteador R2 ainda pode acessar R1, emita o comando ping vrf para fazer ping no R1 a partir do roteador R2.
Ping |
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No roteador R2 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. |