ramesh.chandra at airtel dot in wrote: > Appreciate your query and let us look at simple > Engineering example for a Enterprise house. One > Enterprise customer manage 10 IP pools allocated to him > as per his business demand in previous years. He is > announcing these 10 routes in BGP to upstream carriers, > NAP/NIXI and other private peering he has with others. > Every connected BGP listner has to process every 60 > seconds these 10 routes and install in routing table and > this continues to thousands of routers in Internet. You're probably referring to Cisco's early BGP implementation in IOS where the BGP Scanner process ran every 60 seconds (although it could be tuned to run at much shorter intervals). Software has come a very long way since then, Ramesh, and IOS, in particular, has benefited quite a bit. Gone is the BGP Scanner, which has since been replaced by Next Hop Address Tracking. Next Hop Address Tracking has also been superseded by PIC (Prefix Independent Convergence). All these improvements in software have meant convergence times for BGP have improved greatly, and the 60-second crunch routers have to do is no longer necessary provided they are running the software that supports these new features. > If these 10 pools become one continuous block then these > thousands of routers shall scan and install one route > instead 10 routes in previous case under that AS. This > helps to reduce few CPU cycles and these CPU cycles > become significant when we talk thousand routers > repeating the same. Unless you're talking about route crunching within a single AS, I'd be more concerned about one router processing thousands of routes, as opposed to a thousand routers - each in a different AS - processing a handful of routes. > Lesser routes in BGP required less > time to install and hence faster Convergence time. > Presently, convergence time for 10k IPv4/Ipv6 routes > takes approx 1 second. Convergence time shall reduce > significantly when everyone summarise their own routes > before announcing. Agree, but do you think it is feasible that an entire country, made up of several ISP's, can announce a single IPv6 allocation to the Internet? Serious question. Mark.
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