Este documento proporciona una configuración de ejemplo de una instancia de ruteo y reenvío de VPN (VRF) bajo una interfaz de túnel de GRE (Generic Routing Encapsulation).
Antes de utilizar esta configuración, asegúrese de que cumple con los siguientes requisitos:
Quienes lean este documento deben tener conocimiento de los siguientes temas:
La información en este documento se basa en Cisco IOS® Software Release 12.3(4)T1 en los routers de la serie 3725.
Utilice Cisco Feature Navigator II (sólo clientes registrados) y busque la función GRE Tunnel IP Source and Destination VRF Membership, para obtener los requisitos de software y hardware adicionales que necesite.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
En esta sección encontrará la información para configurar las funciones descritas en este documento.
La configuración se configura de esta manera:
R1-CE y R2-CE se ubican en VRF BLUE.
R1-CE también está ubicado en VRF GREEN a través del uso de un túnel GRE hacia R3-PE.
R1-CE utiliza una ruta de host estática para llegar a R3-PE (destino de túnel), lo que garantiza que no se produzca un ruteo recursivo para el túnel GRE (aprendiendo la dirección de destino del túnel a través del túnel).
VRF BLUE y VRF GREEN son propiedad de dos compañías diferentes y no se producen fugas de ruta entre ellas. Además, la lista de control de acceso (ACL) en la interfaz entre R1-CE y R2-CE se puede utilizar para permitir solamente el tráfico GRE entre ellos.
Nota: Para encontrar información adicional sobre los comandos usados en este documento, utilice la Command Lookup Tool (sólo clientes registrados) .
En este documento, se utiliza esta configuración de red:
Figura 1: Topología físicaFigura 2: Topología lógica de VRF
En este documento, se utilizan estas configuraciones:
R3-PE (punto final del túnel) |
---|
R3-PE# show running-config Building configuration... . ! no ip domain lookup ! ip vrf blue rd 1:1 route-target export 311:311 route-target import 411:411 ! ip vrf green rd 2:2 route-target export 322:322 route-target import 422:422 ! ip cef ! interface Tunnel0 ip vrf forwarding green ip address 200.200.200.3 255.255.255.0 tunnel source Ethernet0/0 tunnel destination 10.10.10.1 tunnel vrf blue !--- Tunnel 0 is part of VRF GREEN; but it uses the tunnel !--- destination and source addresses from the routing !--- table of VRF BLUE, because of this tunnel vrf blue !--- command. ! interface Ethernet0/0 ip vrf forwarding blue ip address 20.20.20.3 255.255.255.0 !--- Connection to the VRF BLUE network and the VRF GREEN !--- network using the GRE tunnel. ! interface Ethernet1/0 ip address 30.30.30.3 255.255.255.0 tag-switching ip ! router bgp 1 no bgp default ipv4-unicast bgp log-neighbor-changes neighbor 30.30.30.4 remote-as 1 ! address-family vpnv4 neighbor 30.30.30.4 activate neighbor 30.30.30.4 send-community extended exit-address-family ! address-family ipv4 vrf green redistribute connected no auto-summary no synchronization exit-address-family ! address-family ipv4 vrf blue redistribute connected no auto-summary no synchronization exit-address-family ! ip classless ip route vrf blue 10.10.10.1 255.255.255.255 20.20.20.2 !--- Static Host route to ensure that recursive routing !--- does not occur. no ip http server ! . end |
R4-PE |
---|
R4-PE# show running-config Building configuration... . . . no ip domain lookup ! ip vrf blue rd 1:1 route-target export 411:411 route-target import 311:311 ! ip vrf green rd 2:2 route-target export 422:422 route-target import 322:322 ! ip cef ! interface Ethernet0/0 ip address 30.30.30.4 255.255.255.0 tag-switching ip ! interface Ethernet1/0 ip vrf forwarding green ip address 100.100.100.4 255.255.255.0 ! interface Ethernet2/0 ip vrf forwarding blue ip address 40.40.40.4 255.255.255.0 ! router bgp 1 no bgp default ipv4-unicast bgp log-neighbor-changes neighbor 30.30.30.3 remote-as 1 ! address-family vpnv4 neighbor 30.30.30.3 activate neighbor 30.30.30.3 send-community extended exit-address-family ! address-family ipv4 vrf green redistribute connected no auto-summary no synchronization exit-address-family ! address-family ipv4 vrf blue redistribute connected no auto-summary no synchronization exit-address-family ! ip classless . . end |
R1-CE (punto final del túnel) |
---|
R1-CE# show running-config Building configuration... . . no ip domain lookup ! ip cef ! interface Tunnel0 ip address 200.200.200.1 255.255.255.0 tunnel source Ethernet0/0 tunnel destination 20.20.20.3 !--- Both the tunnel source and destination address are in !--- the VRF BLUE, to provide transport for the VRF GREEN !--- network. ! interface Ethernet0/0 description Connection to R2-CE router ip address 10.10.10.1 255.255.255.0 ip access-group 100 in ip access-group 100 out !--- Access-group to allow only GRE packets through the !--- R2-CE network. However, R1-CE networks data is in the !--- GRE packet. ! ! ip classless ip route 0.0.0.0 0.0.0.0 Tunnel0 ip route 20.20.20.3 255.255.255.255 10.10.10.2 !--- Static Host route to ensure that recursive routing !--- does not occur. no ip http server ! access-list 100 permit gre host 10.10.10.1 host 20.20.20.3 access-list 100 permit gre host 20.20.20.3 host 10.10.10.1 !--- Permits only GRE packets between the endpoints. ! . . end |
R2-CE |
---|
R2-CE# show running-config Building configuration... . . no ip domain lookup ! ip cef ! interface Ethernet0/0 description Connection to R1-CE router ip address 10.10.10.2 255.255.255.0 ip access-group 100 in ip access-group 100 out ! interface Ethernet1/0 ip address 20.20.20.2 255.255.255.0 ! ip classless ip route 0.0.0.0 0.0.0.0 20.20.20.3 no ip http server ! access-list 100 permit gre host 10.10.10.1 host 20.20.20.3 access-list 100 permit gre host 20.20.20.3 host 10.10.10.1 !--- Permits only GRE packets between the endpoints. . ! end |
R5-CE |
---|
R5-CE# show running-config Building configuration... . . no ip domain lookup ! interface Ethernet0/0 ip address 100.100.100.5 255.255.255.0 ! ! ip classless ip route 0.0.0.0 0.0.0.0 100.100.100.4 no ip http server ! . end |
R6-CE |
---|
R6-CE# show running-config Building configuration... . . no ip domain lookup ! interface Ethernet0/0 ip address 40.40.40.6 255.255.255.0 ! ! ip classless ip route 0.0.0.0 0.0.0.0 40.40.40.4 no ip http server ! . end |
En esta sección encontrará información que puede utilizar para confirmar que su configuración esté funcionando correctamente.
La herramienta Output Interpreter (sólo para clientes registrados) permite utilizar algunos comandos “show” y ver un análisis del resultado de estos comandos.
show ip route , show ip route vrf —Ejecute estos comandos en los puntos finales del túnel para asegurarse de que el destino del túnel sea alcanzable. Esto asegura que la interfaz del túnel se active.
ping : ejecute este comando desde el otro extremo del CE para asegurarse de que los túneles sean accesibles desde el CE.
show ip bgp vpnv4 all label —Ejecute este comando en los dispositivos PE para ver las etiquetas VPN distribuidas para cada prefijo a través del protocolo de gateway fronterizo (BGP) a otros dispositivos PE.
R3-PE# show ip route vrf blue 10.10.10.1 Routing entry for 10.10.10.1/32 Known via "static", distance 1, metric 0 Routing Descriptor Blocks: * 20.20.20.2 Route metric is 0, traffic share count is 1 R3-PE# show ip route vrf green Routing Table: green 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 C 200.200.200.0/24 is directly connected, Tunnel0 100.0.0.0/24 is subnetted, 1 subnets B 100.100.100.0 [200/0] via 30.30.30.4, 01:11:45 R3-PE# show interfaces tunnel 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 200.200.200.3/24 MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 20.20.20.3 (Ethernet0/0), destination 10.10.10.1 Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled Tunnel TTL 255 Checksumming of packets disabled, fast tunneling enabled Last input 00:44:05, output 00:26:16, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/0 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 105 packets input, 11964 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 83 packets output, 10292 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out R3-PE# show ip bgp vpnv4 all labels Network Next Hop In label/Out label Route Distinguisher: 1:1 (blue) 20.20.20.0/24 0.0.0.0 16/aggregate(blue) Route Distinguisher: 2:2 (green) 100.100.100.0/24 30.30.30.4 nolabel/16 200.200.200.0 0.0.0.0 17/aggregate(green) R4-PE# show ip route vrf blue Routing Table: blue 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 20.0.0.0/24 is subnetted, 1 subnets B 20.20.20.0 [200/0] via 30.30.30.3, 01:14:05 R4-PE# show ip route vrf green Routing Table: green 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 B 200.200.200.0/24 [200/0] via 30.30.30.3, 01:14:10 100.0.0.0/24 is subnetted, 1 subnets C 100.100.100.0 is directly connected, Ethernet1/0 R1-CE# show ip route 20.20.20.3 Routing entry for 20.20.20.3/32 Known via "static", distance 1, metric 0 Routing Descriptor Blocks: * 10.10.10.2 Route metric is 0, traffic share count is 1 R1-CE# show interfaces tunnel 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 200.200.200.1/24 MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 10.10.10.1 (Ethernet0/0), destination 20.20.20.3 Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled Tunnel TTL 255 Checksumming of packets disabled, fast tunneling enabled Last input 00:26:57, output 00:26:57, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/0 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 83 packets input, 10292 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 106 packets output, 12088 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out R5-CE# ping 200.200.200.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 200.200.200.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 40/54/80 ms R5-CE# ping 200.200.200.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 200.200.200.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 20/36/72 ms
Actualmente, no hay información específica de troubleshooting disponible para esta configuración.
Estas advertencias conocidas se identifican para la configuración de esta función. Puede utilizar el Bug Toolkit (sólo clientes registrados) para buscar bugs.
CSCea81266 ( sólo para clientes registrados)—Resolved (R) GRE: El tráfico deja de fluir luego de clear ip route *.
CSCdx74855 (sólo clientes registrados) —Resolved (R) No se puede hacer ping a la dirección IP de la interfaz de túnel GRE local.
CSCdx57718 (sólo clientes registrados) —Resuelto (R) Pérdida de paquetes IP en el túnel GRE cuando Cisco Express Forwarding (CEF) se inhabilita en la interfaz saliente.