BGP-4

Info

Multi Protocol - Border Gateway Protocol es la version 4 de BGP y una mejora de BGP-3.

Datos

• Soporta IPv4/IPv6 Unicast/Multicast
• Permite usar AF y expresiones regulares (e.g. ^$)
• Agrega el Atributo NLRI (opcional), es ignorado por sistemas viejos

Configuracion

Nota

La configuracion de ASN y neighbor se hacen de forma global; la activacion del vecino se realiza en una AF especifica. Recuerda habilitar ipv6 unicast-routing

AF iBGP

Nota

La configuracion IPv4 es compatible con BGP-3, solo que se agrega AF

router bgp [BGP-ASN]
 bgp router-id [R-ID]
 neighbor [ipvx-neighbor] remote-as [remote-BGP-ASN]
 neighbor [ipvx-neighbor] update-source loopback [loopback-number]
!
 address-family ipv4
  neighbor [ipv4-neighbor] activate
  network [ipv4-network] mask [dec-mask]
  exit
 address-family ipv6
  neighbor [ipv6-neighbor] activate
  network [ipv6-network/prefix]

AF iBGP Next-Hop-Self

Modifica el atributo “next-hop” a la direccion del router que anuncia las rutas iBGP, se configura en el router de borde que anuncia las rutas

router bgp [BGP-ASN]
 address-family [ipvx]
  neighbor [ip-neighbor] next-hop-self

AF iBGP Next-Hop-Self via Route-map

route-map [map-name] permit [map-value]
 set [ipvx] next-hop [ipvx-next-hop]
 exit
router bgp [BGP-ASN]
 address-family ipv6 unicast
  neighbor [ipvx-neighbor] route-map [map-name] out

AF iBGP Router Reflector

Para que los vecinos se conoscan entre ellos y sus rutas.

router bgp [BGP-ASN]
 address-family [ipvx]
  neighbor [ip-neighbor] route-reflector-client

AF eBGP

router bgp [BGP-ASN]
 bgp router-id [R-ID]
 neighbor [ipvx-neighbor] remote-as [remote-BGP-ASN]
!
 address-family ipv4
  neighbor [ipv4-neighbor] activate
  exit
 address-family ipv6
  neighbor [ipv6-neighbor] activate

Manipular Atributos BGP

Nota

Informacion sobre Manipulacion IPv4: Detalles sobre Proceso de Seleccion de rutas BGP | Relacionado Manipulacion de atributos BGP-3 | Agrega AF a esas configuraciones

Weight IPv6 (Peso)

• Atributo iBGP
• Le da preferencia a una ruta cuando hay multiples rutas de salida.

route-map [map-name] permit
 set weight [weight-value]
 exit
!# Aplica route-map a vecino BGP
router bgp [BGP-ASN]
 address-family ipv6
  neighbor [ipv6-loopback-neighbor] route-map [map-name] {in|out}
  exit
!# Limpia tabla BGP
do clear bgp ipv6 unicast * soft

AS-PATH IPv6

• Atributo eBGP
• Envenena una rutas para preferir otra

route-map [map-name] permit
 set as-path prepend [BGP-ASN-Local] [BGP-ASN-Local]
 exit
router bgp [BGP-ASN]
 address-family ipv6
  neighbor [ipv6-neighbor] route-map [map-name] {in|out}
  exit
!# Limpia tabla BGP
do clear bgp ipv6 unicast * soft

MED IPv6

Atributo iBGP-eBGP Multiple Exit Discriminator

route-map [map-name] permit
 set metric [metric-value]
 exit
router bgp [BGP-ASN]
 address-family ipv6
  neighbor [ipv6-neighbor] route-map [map-name] {in | out}
  exit
!# Limpia tabla BGP
do clear bgp ipv6 unicast * soft

Sumarizar Redes

Apoyo sobre Sumarizacion de Redes

router bgp [BGP-ASN]
 address-family ipv6
  aggregate-address [ipv6-sum-network/prefix] summary-only

Visualizacion

• show bgp ipv6 unicast: Tabla BGP IPv6 unicast
• show bgp ipv6 unicast summary: Tabla BGP IPv6 Resumen
• show bgp ipv6 unicast nexthop
• show run | section router bgp: Ver configuracion de BGP

Troubleshooting

• “Active” no esta configurado en AF IPv6
  • show bgp ipv6 unicast
• Falta limpiar la tabla de los intentos fallidos
  • clear bgp ipv6 unicast * soft

Extra

• En MPLS se utiliza para intercambiar etiquetas VPN
• Dentro de los AF no hay tabuleos