[zebra 22908] Re: (Not So) Full Routes from Two BGP Peers

David Schwartz wrote:
>> >From one provider I currently see 188086 prefixes, which seems to be
>> about right.  But the other is only showing 13019.  A quick review of
>> the received routes from the provider that is coming up short seems to
>> show that it is only giving me routes that have an AS path no greater
>> than two hops beyond their own system.  That is to say the only routes
>> I'm getting from them, have path of three or less AS numbers.
> 
> 	One of two things is most likely the case:
> 
> 	1) The other provider is providing better routes (as BGP defines 'better')
> and you are only showing the routes that are chosen, not all the routes you
> are receiving.

I don't think this is the case.  For one, the provider that is showing
the fewer routes is technically the 'better' connected provider, and
should be the one that 'wins' in most cases (and indeed does get about
11,000 of their 13,000 prefixes into the kernel).  Also I'm basing my
numbers on what Zebra's bgpd reports, not the kernel's routing table.
Skimming "show ip bgp" only has about 1 in 10 of the entries with  a
pair of prefixes with one being marked 'best'.  Last, the numbers I
quoted above came directly from "show ip bgp summary".

> 	2) The provider is only sending you some subset of the routing table (only
> customers, perhaps), not full routes.

This is what I think, but you know how some providers are.  Thanks for
the verification.

> 	DS

-- 
Chris