Hi Nick, I am guessing here you are talking about split-horizon for BGP rather than split-horizon for distance-vector routing protocols such as RIP? I'll work with both anyway.
With an IGP - Split-horizon simply does not advertise a route back to an interface it received an advertisment from.. A---1----2------3-----B A & B are networks, 1,2 & 3 are routers. 1 advertises network A to router 2. Router 2 then advertises to 3. Router 2 will not advertise A back to 1, as 1 already knows about network A. BGP is the same, but think of 1, 2 & 3 as AS numbers rather than routers. Now - the synchronisation rule. Another easy one... BGP wont advertise a route until it is learned via an IGP. So think of the IGP trying to catch up, and when it does BGP starts talking. Cheers, Matt CCIE #22386 CCSI #31207 2009/10/6 nicholas golden <[email protected]> > Hey everyone, as most of you it seems are going for the lab, I am still > working on the written because I am just that cool. But what's not cool is > my brain right now and I think my brain refuses to learn something about > Synchronization vs split horizon in BGP. > > Can I get a "for dummies" explanation of this with either a diagram, cheat > sheet or some silly crayon drawing of how these things work. My biggest > weakness in learning this material is I am almost lopsided on how I learn > which is visually, but I am working on it. > > I've hit the bible volume 2 of doyle, I have hit cisco, I have hit various > things and of course Ipexpert VOD, but I think I just got hit by the retard > stick. Maybe it will pass soon, so with that I could use another explanation > in stupid terms on how this works so I may jump for joy :) > > Thanks a bunch. I am sure once I get this nailed, I'll be coming back for > regular expressions :) > > -Nick > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > >
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
