El Border Gateway Protocol (BGP) se utiliza entre sistemas autónomos (AS) para transmitir información de enrutamiento. BGP se aplica a redes grandes y complejas.
El Border Gateway Protocol (BGP) es un protocolo de vector de ruta que permite comunicarse a los dispositivos entre sistemas autónomos (AS) y seleccionar rutas óptimas. BGP-1 (definido en RFC 1105), BGP-2 (definido en RFC 1163) y BGP-3 (definido en RFC 1267) son tres versiones anteriores de BGP. BGP-4 (definido en RFC 1771) se ha utilizado desde 1994. Desde 2006, las redes IPv4 de unidifusión han estado usando BGP-4 definida en RFC 4271, y otras redes (como las redes IPv6) han estado utilizando MP-BGP definida en RFC 4760.
Una red se divide en diferentes AS para facilitar la gestión a través de la red. En 1982, se utilizó Exterior Gateway Protocol (EGP) para intercambiar dinámicamente información de enrutamiento entre los AS. EGP anuncia solo las rutas accesibles, pero no selecciona rutas óptimas ni evita los bucles de enrutamiento. Por lo tanto, EGP no puede cumplir con los requisitos de administración de red.
BGP fue diseñado para reemplazar EGP. A diferencia de EGP, BGP puede seleccionar rutas óptimas, evitar bucles de enrutamiento, transmitir información de enrutamiento de manera eficiente y mantener un gran número de rutas.
A continuación se presenta un ejemplo de configuración para establecer la sesión de BGP entre un equipo Juniper y un Huawei, con la finalidad de demostrar la compatibilidad entre estos.
JUNIPER:
bgp 65194
peer 10.10.150.1 as-number 8151
#
ipv4-family unicast
undo synchronization
peer 10.10.150.1 enable
interfaces {
ge-0/0/0 {
unit 0 {
family inet {
address 10.10.150.1/30;
}
}
}
routing-options {
autonomous-system 8151;
}
protocols {
bgp {
group EBGP {
type external;
peer-as 65194;
neighbor 10.10.150.2;
}
}
}
HUAWEI
#
interface GigabitEthernet0/0/2
ip address 10.10.150.2 255.255.255.252
#
bgp 65194
peer 10.10.150.1 as-number 8151
#
ipv4-family unicast
undo synchronization
peer 10.10.150.1 enable
#
VERIFICACIÓN
[AR2220E]dis bgp peer
Status codes: * - Dynamic
BGP local router ID : 192.168.1.1
Local AS number : 65194
Total number of peers : 1 Peers in established state : 1
Total number of dynamic peers : 0
Peer V AS MsgRcvd MsgSent OutQ Up/Down State PrefRcv
10.10.150.1 4 8151 8 7 0 00:02:25 Established 0
[AR2220E]dis bgp peer verbose
BGP Peer is 10.10.150.1, remote AS 8151
Type: EBGP link
BGP version 4, Remote router ID 10.10.150.1
Update-group ID: 1
BGP current state: Established, Up for 00h02m37s
BGP current event: RecvKeepalive
BGP last state: OpenConfirm
BGP Peer Up count: 1
Received total routes: 0
Received active routes total: 0
Received mac routes: 0
Advertised total routes: 0
Port: Local - 179 Remote - 51901
Configured: Connect-retry Time: 32 sec
Configured: Min Hold Time: 0 sec
Configured: Active Hold Time: 180 sec Keepalive Time:60 sec
Received : Active Hold Time: 90 sec
Negotiated: Active Hold Time: 90 sec Keepalive Time:30 sec
Peer optional capabilities:
Peer supports bgp multi-protocol extension
Peer supports bgp route refresh capability
Peer supports bgp 4-byte-as capability
Address family IPv4 Unicast: advertised and received
Received: Total 9 messages
Update messages 0
Open messages 1
KeepAlive messages 8
Notification messages 0
Refresh messages 0
Sent: Total 8 messages
Update messages 0
Open messages 1
KeepAlive messages 7
Notification messages 0
Refresh messages 0
Authentication type configured: None
Last keepalive received: 2018/01/16 08:00:40
Last keepalive sent : 2018/01/16 08:00:34
Minimum route advertisement interval is 30 seconds
Optional capabilities:
Route refresh capability has been enabled
4-byte-as capability has been enabled
Peer Preferred Value: 0
Routing policy configured:
No routing policy is configured
root# run show bgp summary
Groups: 1 Peers: 1 Down peers: 0
Table Tot Paths Act Paths Suppressed History Damp State Pending
inet.0 0 0 0 0 0 0
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.10.150.2 65194 46 54 0 1 3:50 0/0/0/0 0/0/0/0
root# run show bgp neighbor
Peer: 10.10.150.2+179 AS 65194 Local: 10.10.150.1+51901 AS 8151
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: Cease
Options: <Preference PeerAS Refresh>
Holdtime: 90 Preference: 170
Number of flaps: 1
Last flap event: Stop
Error: 'Cease' Sent: 1 Recv: 0
Peer ID: 192.168.1.1 Local ID: 10.10.150.1 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 0
BFD: disabled, down
Local Interface: ge-0/0/0.0
NLRI for restart configured on peer: inet-unicast
NLRI advertised by peer: inet-unicast
NLRI for this session: inet-unicast
Peer supports Refresh capability (2)
Stale routes from peer are kept for: 300
Peer does not support Restarter functionality
Peer does not support Receiver functionality
Peer supports 4 byte AS extension (peer-as 65194)
Peer does not support Addpath
Table inet.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 0
Received prefixes: 0
Accepted prefixes: 0
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 11 Sent 11 Checked 71
Input messages: Total 47 Updates 5 Refreshes 0 Octets 1096
Output messages: Total 55 Updates 0 Refreshes 0 Octets 1127
Output Queue[0]: 0
