I can't think of a situation where leaving split horizon on would create a loop (it is a loop prevention technology), usually it would just keep some routes from being learned on the spokes. You won't see if set on the interfaces, the default is that it is enabled, but it doesn't show in running config unless you disable it.
On Sat, Jul 16, 2011 at 2:00 AM, Alef <[email protected]> wrote: > Thanks Marc. > Yeah i think you want to disable it usually on multipoint interfaces ? > Although i haven't been doing that actively and things still seem to work ok > (but then again i might just have introduced a loop in my network) > > Maybe i just haven't been paying attention, but i don't think i usually see > it on the interfaces in the running config. Is it still enabled and we just > don't see it ? > > Many thanks for your replies, it is much appreciated. > Alef > > On Jul 15, 2011, at 11:29 PM, marc abel wrote: > >> It is on by default, on pretty much every int type and for every >> protocol. OSPF however isn't affected by it because it really doesn't >> advertise routes. It advertises LSA's from which routers then build >> their routes from. So practically you just need to worry about the >> distance vector protocols EIGRP and RIP. >> >> It is of particular importance to disable split horizon on the hub >> when you have EIGRP or RIP running on a frame relay or PPP hub and >> spoke topology. >> >> On Fri, Jul 15, 2011 at 3:54 PM, Alef <[email protected]> wrote: >>> Hi Marc, >>> I thought i did put the lab number in the subject header? >>> >>> I guess i have to do some more learning about split horizon. I didn't know >>> it was by default enabled? Is it an EIGRP thing ? >>> >>> Thanks again, >>> Alef >>> On Jul 15, 2011, at 8:19 PM, marc abel wrote: >>> >>>> Because Cat4 is learning the route from BB2on it's vlan50 interface. >>>> With split horizon enabled it will not advertise that route back out >>>> it's vlan50 interface so you won't be able to learn it on R8 from >>>> cat4. If Cat4 were originating the route, or learning it on a >>>> different interface this wouldn't be an issue. >>>> >>>> Make sense? >>>> >>>> P.S. You may want to include the lab # in your questions. I got lucky >>>> with your first question and guessed right. >>>> >>>> On Fri, Jul 15, 2011 at 12:48 PM, Alef <[email protected]> wrote: >>>>> Anyone working on this task? Instead of getting the routes from BB2, R8 >>>>> needs to get them from Cat4. >>>>> >>>>> The task does not really explain why we need to disable split horizon on >>>>> vlan50 interface on cat4. >>>>> Could anyone provide a good explanation ? >>>>> _______________________________________________ >>>>> For more information regarding industry leading CCIE Lab training, please >>>>> visit www.ipexpert.com >>>>> >>>>> Are you a CCNP or CCIE and looking for a job? Check out >>>>> www.PlatinumPlacement.com >>>>> >>> >>> > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
