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RS0070 - BGP Confederation (Part 2)
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Lab Document:
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Category:
Routing & Switching
The video provides an alternative approach of building a scalable BGP topology on Cisco router using confederation. We will go through what you need to know about concept of sub-autonomous system, possible topology, and changes in route advertisement behavior compared to the regular iBGP and eBGP. We will also review some of the BGP attributes and how they are treated within confederation.
Part 2 of this video goes over Bhow eBGP routes are treated and review some BGP attributes
Topic:
- Confederation - iBGP
- Confederation - eBGP
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BGP Attributes
- Local Preference
- MED
- Community (Local-AS)
2 comments
ip bgp / ip cef
Hi, could you tell me why ip bgp 7.7.0.0 shows next hop to R3 while ip cef pointing at R4 ? (movie time 4:32).. I am struggling with it :(
ip bgp / ip cef
As R2 learns the route from R7 and advertises within its AS, R2 sets the route nexthop to itselfs. Eventually this route is learnt by R6 from R3 and R4 but R6 prefers R3 route due to shorter path. Inside that route, the nexthop is R2 loopback0. When R6 tries to get to R2, it uses IGP metric and since it can get to R2 via R4 with 2-hops as opposed to 3-hops via R3, it routes traffic to R4.