Prefix-Lists and BGP, fundamentals and configuration explained, important behaviors and more to know for exam day!

BGP Prefix lists are important for their high flexibility, support for incremental updates, and that writing BGP Prefix lists are much more efficient than writing ACL's that filter BGP updates as BGP tables can have much more content (thousands of entries) in them as compared to IGP's route tables. They have some similarities to ACL's … Continue reading Prefix-Lists and BGP, fundamentals and configuration explained, important behaviors and more to know for exam day!

BGP Route Reflector configuration, explanation / need for them, and important behaviors / verification commands!

A router configure to be a BGP Route Reflector can take a route learned from one iBGP Peer and advertise it to another iBGP Peer, which basically is the equivalent of "no ip split-horizon" only BGP style! iBGP Peers that send routes to the route reflector are called "clients", and when the Reflector receives routes … Continue reading BGP Route Reflector configuration, explanation / need for them, and important behaviors / verification commands!

BGP – The Multi-Exit Discriminator (MED) / Metric explained, configured, and we see some old friends ACL’s and Route-Maps to help accomplish the goal!

So as can be seen we have no NBMA in this topology, only Serial Links and an Ethernet segment, which almost makes feel naked without a Frame-Switch in there somewhere. So to begin, my last post included on the tail end a "sh ip bgp" to demonstrate something with a bunch of loopbacks being advertied … Continue reading BGP – The Multi-Exit Discriminator (MED) / Metric explained, configured, and we see some old friends ACL’s and Route-Maps to help accomplish the goal!

eBGP Route Advertisement explained, troubleshooting BGP RIB Failure, and good to know eBGP behaviors for exams and real life!

So lets get this party started with the dry stuff we all love, theory and concepts. BGP uses the "network" command in router configuration, which is basically the same as a network statement for OSPF or EIGRP, except for a couple differences you will see during configuration. The real differences however are in how IGP's … Continue reading eBGP Route Advertisement explained, troubleshooting BGP RIB Failure, and good to know eBGP behaviors for exams and real life!