BGP troubles

karnivore

Hi, i'm just tried my first BGP configuration but then came up a question, do I must ping each other router with its loopback ip? or there is any command to enable ping to other neighbor? i'm asking that stuff cos I tried to do it but i couldn't do it neither with ethernet nor with hdlc. If someone can help me with that stuff I'll thank you.

darkuser

bgp uses tcp/179 as a transport so .... yes you need tcp/179 to be reachable at a minnimum to establish a peering session.
you should peer between serial ip's for your first config.
peering between loopbacks may require a static route to the next hop home of the loopback. (if it's not learned via a dynamic routing protocol)
that's your choice though.
bgp also needs an underlying igp in order to work.
and finally you need to use update-source to tell bgp that the source of the peering session is a loopback and not a local interface.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt2/1cfbgp.htm

Ten9t6

darkuser is correct..you need an IGP. For IGBP you peer to loopbacks for reachability...for EBGP you peer to interfaces.

Kenny

farisb

You can also use EBGP to peer with the loopbacks but you must use the ebgp-multihop command. You must still use a IGP to get to the loopback address. To prevent the creation of loops through oscillating routes, the multihop will not be established if the only route to the multihop peer is the default route (0.0.0.0).

karnivore

Hi, yesterday I pass my BSCI exam with 976 points. Thanks fo your help without it I couldn't do it, it helped me to start me lab in BGP. Next BCRAN, hope will be allright.