Este documento proporciona una configuración de ejemplo usando IPv6 que le ayuda a configurar el Filtrado de Rutas Salientes Basado en Prefijos BGP. Esta función utiliza las capacidades de envío y recepción de filtro de ruta de salida BGP (ORF) que minimizan el número de actualizaciones de BGP enviadas entre routers de peer. La configuración de esta función puede ayudar a filtrar las actualizaciones de ruteo no deseadas en el origen.
Asegúrese de cumplir estos requisitos antes de realizar esta configuración:
Conocer el protocolo de ruteo BGP y su funcionamiento
Conocer el esquema de direccionamiento IPv6
Este documento no tiene restricciones específicas en cuanto a versiones de software y de hardware.
Las configuraciones en este documento se basan en el Cisco 7200 Series Router con Cisco IOS® Software Release 15.0(1).
En este ejemplo, el router R1 se configura para advertise-prefix basado ORF send capabilities al router R2. En el otro extremo, el router R2 se configura para anunciar las capacidades de recepción ORF basadas en prefijo al router R1. Antes de que la función BGP Prefix-Based Outbound Route Filtering pueda ser habilitada para enviar o recibir anuncios ORF basados en prefijo, las sesiones de peering BGP deben estar en funcionamiento y las capacidades BGP ORF deben estar habilitadas en cada router participante antes de un router.
Este documento utiliza el comando neighbor o prefix-filter para habilitar la capacidad de lista de prefijos ORF en el router. Este comando se introdujo en la versión 12.0(11)ST del software del IOS de Cisco.
Nota: Use la Command Lookup Tool (sólo para clientes registrados) para encontrar más información sobre los comandos usados en este documento.
En este documento, se utiliza esta configuración de red:
En este documento, se utilizan estas configuraciones:
Router R1 |
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! hostname R1 ! ipv6 unicast-routing ipv6 cef ! ! interface Loopback1 no ip address ipv6 address 1111::1/128 ! ! interface Loopback2 no ip address ipv6 address 2222::1/128 ! ! interface Serial1/0 no ip address ipv6 address 2011:11:11:11::1/64 serial restart-delay 0 ! ! router bgp 6501 no synchronization no bgp default ipv4-unicast bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 2011:11:11:11::2 remote-as 6502 neighbor 2011:11:11:11::2 ebgp-multihop 255 no auto-summary ! address-family ipv6 neighbor 2011:11:11:11::2 activate neighbor 2011:11:11:11::2 capability orf prefix-list send neighbor 2011:11:11:11::2 prefix-list FILTER_IPv6 in exit-address-family ! ! ipv6 prefix-list FILTER_IPv6 seq 10 permit 1111::1/128 ipv6 prefix-list FILTER_IPv6 seq 20 permit 2222::1/128 ! ! end |
Router R2 |
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! hostname R2 ! ! no ip domain lookup ipv6 unicast-routing ipv6 cef ! interface Loopback1 no ip address ipv6 address 1010::1/128 ! ! interface Loopback2 no ip address ipv6 address 2020::1/128 ! interface Serial1/0 no ip address ipv6 address 2011:11:11:11::2/64 serial restart-delay 0 ! ! router bgp 6502 no synchronization bgp router-id 2.2.2.2 bgp log-neighbor-changes neighbor 2011:11:11:11::1 remote-as 6501 neighbor 2011:11:11:11::1 ebgp-multihop 255 no auto-summary ! address-family ipv6 network 1010::1/128 network 2020::1/128 neighbor 2011:11:11:11::1 activate neighbor 2011:11:11:11::1 capability orf prefix-list receive neighbor 2011:11:11:11::1 prefix-list R2_list in exit-address-family ! ipv6 prefix-list R2_list seq 10 permit 1010::1/128 ipv6 prefix-list R2_list seq 20 permit 2020::1/128 ! end |
En este escenario, se configura una dirección de loopback 1000::1/45 en R1 bajo loopback 0 de interfaz . Se crea una lista de prefijos para permitir cualquier ruta que sea mayor que la longitud del prefijo ::/64.
Nota: La configuración del router R2 sigue siendo la misma que la anterior y los cambios de configuración de R1 como se muestra aquí. Las direcciones IP de estos routers siguen siendo las mismas.
Router R1 |
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!--- Output omitted. ! interface Loopback0 no ip address ipv6 address 1000::1/45 ! !--- Output omitted. router bgp 6501 no synchronization bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 2011:11:11:11::2 remote-as 6502 neighbor 2011:11:11:11::2 ebgp-multihop 255 no auto-summary ! address-family ipv6 network 1000::1/45 network 1111::1/128 network 2222::1/128 neighbor 2011:11:11:11::2 activate neighbor 2011:11:11:11::2 prefix-list IPV6-LONG in !--- Applies the prefix-list and filters !--- the incoming updates from the neighbor 2011:11:11:11::2. exit-address-family ! ipv6 prefix-list IPV6-LONG description Match any prefix longer than /64 ipv6 prefix-list IPV6-LONG seq 1 permit ::/0 ge 64 !--- seq 1 permit ::/0 ge 64 permits anything !--- that is ge /64 subnet mask. ! end |
Use esta sección para confirmar que su configuración funciona correctamente.
La herramienta Output Interpreter Tool (clientes registrados solamente) (OIT) soporta ciertos comandos show. Utilice la OIT para ver un análisis del resultado del comando show.
Estos comandos show se utilizan para verificar la configuración:
show running-config | beg bgp
show bgp ipv6 unicast neighbors
En el Router R1:
show running-config | beg bgp |
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router bgp 6501 no synchronization bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 2011:11:11:11::2 remote-as 6502 neighbor 2011:11:11:11::2 ebgp-multihop 255 no auto-summary ! address-family ipv6 neighbor 2011:11:11:11::2 activate neighbor 2011:11:11:11::2 capability orf prefix-list send !--- Indicates that the neighbor 2011:11:11:11::2 !--- is configured with the prefix-based !--- ORF feature in send mode. |
show bgp ipv6 unicast neighbors |
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R1#show bgp ipv6 unicast neighbors 2011:11:11:11::2 BGP neighbor is 2011:11:11:11::2, remote AS 6502, external link BGP version 4, remote router ID 2.2.2.2 Session state = Established, up for 01:30:36 Last read 00:00:44, last write 00:00:42, hold time is 180, keepalive interval is 60 seconds BGP multisession with 2 sessions (2 established), first up for 01:31:26 Neighbor sessions: 2 active, is multisession capable Neighbor capabilities: Route refresh: advertised and received(new) on session 1, 2 Four-octets ASN Capability: advertised and received on session 1, 2 Address family IPv4 Unicast: advertised and received Address family IPv6 Unicast: advertised and received !--- Output omitted. For address family: IPv6 Unicast Session: 2011:11:11:11::2 session 2 BGP table version 1, neighbor version 1/0 Output queue size : 0 Index 2 session 2 member 2 update-group member AF-dependant capabilities: Outbound Route Filter (ORF) type (128) Prefix-list: !--- Shows that the neighbor 2011:11:11:11::2 !--- is configured with the prefix-based !--- ORF feature in send mode. Send-mode: advertised Receive-mode: received Outbound Route Filter (ORF): sent; Incoming update prefix filter list is FILTER_IPv6 Sent Rcvd Prefix activity: ---- ---- Prefixes Current: 2 4 Prefixes Total: 0 0 Implicit Withdraw: 1 0 Explicit Withdraw: 1 0 Used as bestpath: n/a 0 Used as multipath: n/a 0 Outbound Inbound Local Policy Denied Prefixes: -------- ------- !--- Output omitted. |
En el Router R2:
show running-config | beg bgp |
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router bgp 6502 no synchronization bgp router-id 2.2.2.2 bgp log-neighbor-changes neighbor 2011:11:11:11::1 remote-as 6501 neighbor 2011:11:11:11::1 ebgp-multihop 255 no auto-summary ! address-family ipv6 network 1010::1/128 network 2020::1/128 neighbor 2011:11:11:11::1 activate neighbor 2011:11:11:11::1 capability orf prefix-list receive !--- Indicates that the neighbor 2011:11:11:11::1 !--- is configured with the prefix-based !--- ORF feature in receive mode. |
show bgp ipv6 unicast neighbors |
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R2#show bgp ipv6 unicast nei 2011:11:11:11::1 BGP neighbor is 2011:11:11:11::1, remote AS 6501, external link BGP version 4, remote router ID 1.1.1.1 Session state = Established, up for 01:47:11 Last read 00:00:44, last write 00:00:32, hold time is 180, keepalive interval is 60 seconds multisession with 2 sessions (2 established), first up for 01:48:02 Neighbor sessions: 2 active, is multisession capable Neighbor capabilities: Route refresh: advertised and received(new) on session 1, 2 Four-octets ASN Capability: advertised and received on session 1, 2 Address family IPv4 Unicast: advertised and received Address family IPv6 Unicast: advertised and received Multisession Capability: advertised and received !--- Output omitted. For address family: IPv6 Unicast Session: 2011:11:11:11::1 session 2 BGP table version 3, neighbor version 3/0 Output queue size : 0 Index 3 session 2 member 3 update-group member AF-dependant capabilities: Outbound Route Filter (ORF) type (128) Prefix-list: !--- Shows that the neighbor 2011:11:11:11::1 !--- is configured with the prefix-based !--- ORF feature in receive mode. Send-mode: received Receive-mode: advertised Outbound Route Filter (ORF): received (2 entries) Incoming update prefix filter list is R2_list Sent Rcvd Prefix activity: ---- ---- Prefixes Current: 2 5 Prefixes Total: 0 0 Implicit Withdraw: 0 0 Explicit Withdraw: 2 0 !--- Output omitted. |
Ejecute el comando show ipv6 route bgp en el router R1 para mostrar el contenido actual de la tabla de ruteo BGP IPv6.
show ipv6 route bgp |
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En el router R1: R1#show ipv6 route bgp IPv6 Routing Table - default - 9 entries Codes: C - Connected, L - Local, S - Static, U - Per-user Static route B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary D - EIGRP, EX - EIGRP external, ND - Neighbor Discovery O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2 ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2 B 1010::1/128 [20/0] via 2011:11:11:11::2 B 2020::1/128 [20/0] via 2011:11:11:11::2 !--- In this ouput, 1000::1/45 is not !--- displayed because the network is lesser !--- than ::/64 prefix and its filtered. |
Utilice el comando show ipv6 prefix-list para mostrar información sobre una lista de prefijos IPv6 o entradas de lista de prefijos IPv6.
show ipv6 prefix-list |
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En el router R1: R1#show ipv6 prefix-list detail Prefix-list with the last deletion/insertion: IPV6-LONG ipv6 prefix-list IPV6-LONG: Description: Match any prefix longer than /64 count: 1, range entries: 1, sequences: 1 - 1, refcount: 3 seq 1 permit ::/0 ge 64 (hit count: 14, refcount: 1) R1#show ipv6 prefix-list summary Prefix-list with the last deletion/insertion: IPV6-LONG ipv6 prefix-list IPV6-LONG: Description: Match any prefix longer than /64 count: 1, range entries: 1, sequences: 1 - 1, refcount: 3 R1#show ipv6 prefix-list IPV6-LONG ipv6 prefix-list IPV6-LONG: 1 entries seq 1 permit ::/0 ge 64 |
Revisión | Fecha de publicación | Comentarios |
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1.0 |
14-Jun-2012 |
Versión inicial |