Cisco R&S: Frequent commands used when configuring BGP

Posted on Updated on


#router bgp 100 –  only one BGP process per router

#network x.x.x.x mask x.x.x.x – using this command will not automatically form a neighbor relationship

#neighbor x.x.x.x remote-as x.x.x.x – peer router

#timers bgp x x – change the keepalive and holdtime timers respectively

#neighbor x.x.x.x update-source Loopback 0 – Instruct the router to use an operational interface for TCP connections with the neighbor. Preferably a loopback interface

#neighbor x.x.x.x ebgp multihop x – only for ebgp routers that are not directly connected to establish a session. x is the number of hops to the neighbor.

#neighbor x.x.x.x soft-reconfiguration inbound – router stores all updates  from the neighbour incase the inbound policy is changed. Memory intensive

#synchronization – router can now announce routes learnt via iBGP even if these routes are unknown via IGP

#neighbor x.x.x.x default-originate – default route will only be sent to the specified neighbor

network 0.0.0.0 – advertises a default route to all peers

maximum-paths 3 – load balancing over 3 equal paths

maximum-paths ibgp 3

maximum-paths ebgp 3

neighbor x.x.x.x password xxxx – router and peer will use md5 authentication  for TCP connection between them. Must be same on both.

neighbor x.x.x.x next-hop-self – this router will be used as the next hop to advertise all updates to the indicated neighbour.

neighbor x.x.x.x next-hop-unchanged – nexthop is unchanged

neighbor x.x.x.x remove-private-as – only for ebgp neighbours. it removes private AS numbers before propagating to the Internet.

neighbor x.x.x.x weight xxx – set the weight of all updates from the neighbour to xxx. Not propagaetd to other routers.

bgp default local-preference 150  – set the default local preference.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s