BGP:advertising networks

Unanswered Question
Nov 5th, 2008


According to the diagram and the config, why isn't there a "network mask" on router B? Does the "network" statement advertise only connected networks?

please check the attached files (taken from Cisco Student Guide).

I have this problem too.
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rais Wed, 11/05/2008 - 13:04 is not owned by routerB. It belongs to A. network statement on B would advertise connected routes from B.


hasmurizal Wed, 11/05/2008 - 22:16


The network statement does necessarily advertised connected networks, it is just to advertise the router self network into bgp.

If you wanted to advertise the connected network, just include in the router bgp config "redistribute connected"

Giuseppe Larosa Thu, 11/06/2008 - 00:47

Hello Wassim,

as Milan has correctly noted is RA that is advertising net on its iBGP session to RB.

RB can then advertise to RC over an eBGP session the network and will change the BGP next-hop attribute to ip 10.1.1.x (BGP next-hop recalculation at EBGP session).

From the point of view of RC there is no difference between the two subnets:

both comes over eBGP with AS path= 65000 i

BGP next hop= 10.1.1.x

Hope to help



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