To achieve a full mesh of iBGP peerings between more than a few devices becomes quite an administrative challenge. To overcome this you have two tools at your disposal. BGP Confederation and Route Reflectors. For the purpose of this tutorial I will be using the simple topology below. For the first configuration I will be […]
The Border Gateway Protocol (BGP) is an exterior gateway protocol designed to exchange routing and reachability information between autonomous systems (AS) on the internet and now more commonly in enterprise networks.
A BGP router with synchronization enabled does not install iBGP learned routes into its routing table if it is not able to validate those routes in its IGP. The BGP syncronization rule states that if your AS passes traffic from another AS to a third AS, BGP should not advertise a route before all the […]
If you have started to look at BGP you will very soon come across the BGP update-source command. This command tells BGP which interface to source the BGP packets out of. The short demo below will highlight the problem. I have a very simple setup with 2 routers connected with a serial interface and an […]
If you are trying to find the BGP best path selection algorithm on the DOC CD it has been removed from the 12.4 documentation for some crazy reason! You will need to go back to the 12.2 documentation The full path is www.cisco.com / support / configure / producst / cisco ios and ns-ox software […]