The as which originated the prefix is carried in the packet, along with the as you are receiving the prefix from. There is no cache or other table which tells the router which ip address belongs to which as--that's what BGP's job is, to provide this information. :-)
Each ISP has a unique as, assigned by a set of central numbering authorities. Organizations can also get their own as, by applying to these same numbering authorities.
AS NUMBERS and BGP ROUTING is how routers in the internet decide where to route IP packets. BGP is used to building the routing table. Thats all.
Every packet that comes into the router is forwarded
to the entry for that prefix (range of ip's) in the routing table. AS numbers have nothing to do the routing process. Each packet is not inspected, and each packet dosent contain an AS number. only BGP
packets used between routers running BGP contain
AS information, These are special packets passed
by bgp peers to as part of the bgp process.
Bottom Line: Do Not confuse the BGP route deciding
process (or any routing protcol, or static routes)
from the routing routers do once they have learned
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
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[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
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IntroductionOSPF, being a link-state protocol, allows for every router
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