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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: AS_PATH length and route selection (WAS: Strange BGP announcement)
The key to this is that the administrative preference in question has domain scope. Assuming you are correctly implementing iBGP, whether with a full mesh, reflectors, or confederations, and assuming consistent announcements from external route originators, then you can't make a loop because the same policy is in effect for all the routers in the AS. Incomplete iBGP implementations and router-local administrative preferences can easily be used to create loops, but that is certainly not a problem with BGP. Ben On Tue, Nov 17, 1998 at 05:49:21PM -0800, Tony Li wrote: > > | This, of course, leads to many, many other questions (such as the > | possibility routing loops caused by different local policies as was seen > | with implementations of BGP4), but few of which are of a truly operational > | issue. So I will apologize for starting a thread based on mis-information > | and go back to my cave. > > > Different local policies should all be reflected in the LOCAL_PREF, which > should be distributed to all nodes within the domain. This should lead to > consistent decisions within the domain and thus should avoid stable > forwarding loops. > > Tony
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