Full Mesh iBGP Cores

One possible way to design an iBGP core is to mesh fully each of the iBGP speakers in the core—each iBGP speaker must have a direct peering relationship with each other iBGP speaker. The first set of questions that comes to mind is, Why is this? What property of iBGP requires that all the iBGP speakers in a given autonomous system must be peered to one another? What impact does this rule have on the scaling of the iBGP core? These questions are discussed in the following sections.

Why Full Mesh?

There's a simple rule in BGP that states, When a BGP speaker receives an UPDATE message from an internal peer, the receiving BGP speaker shall not redistribute the routing information contained in that UPDATE message to other internal ...

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