With BGP spilt horizon rule, how can i make routing?

With BGP spilt horizon rule, how can i make routing if router will not advertise routes that learned from another IBGP router.

Reply to
cisco_crazy
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That is not what split horizon does.

All distance vector routing protocols can optionally apply split horizon - I seem to recall.

With split horizon enabled the routing protocol does not advertise routes out of the same interface that they were learned on. Mostly there is no need to do this since the sender already has the routes - obviously.

For certain network topologies (point to multipoint frame relay seems to ring a bell) it may be necessry to disable split horizon, hence it is an option. I think that mostly it is on by default - not sure about BGP.

Time for you - and me - to get back to the books.

This is the place to start, I have it and it is superb:- # Routing TCP/IP, Volume 1 (2nd Edition) (CCIE Professional Development) by Jeff Doyle [No BGP here I think but it explains all the basics, I think you need this before tackling BGP]

This is supopsed to be *the* BGP book:- Internet Routing Architectures (2nd Edition) (Networking Technology) (Hardcover) by Sam Halabi (Author)

This also covers BGP in depth but I have not read it. Volume one is very, very good. # Routing TCP/IP, Volume II (CCIE Professional Development) by Jeff Doyle

If you don't have routers to play with you can use dynamips if you have a decent modern PC; or maybe two for complex topologies - it just works.

Reply to
bod43

You could use a route-reflector, if you can't fully mesh your iBGP peers.

Cheers,

Matt

Reply to
Matthew Melbourne

"Split Horizon" is a term that is used to describe the behavior that you cite above for distance vector protocols such as RIP.

With BGP, the term "Split Horizon" is used in a different context. BGP "Split Horizon" is as follows.

'Do not advertise a route that you learn from an iBGP neighbor to another iBGP neighbor.'

Yes, perhaps you can hit the books and learn some more on this. You'll discover why 'full mesh' internal topologies are required in order to propagate routes, and learn how 'route reflectors' over come the issue, as another poster correctly pointed out.

-j

Reply to
John Agosta

Thank you allllllllllll

Reply to
cisco_crazy

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