Getting pretty close to default IPv4 route maximum for 6500/7600 routers.

Blake Hudson blake at
Tue Jun 10 17:39:48 UTC 2014

Łukasz Bromirski wrote the following on 6/10/2014 12:15 PM:
> Hi Blake,
> On 10 Jun 2014, at 19:04, Blake Hudson <blake at> wrote:
>> In this case, does the 512k limit of the 6500/7600 refer to the RIB or the FIB? And does it even matter since the BGP prefix table can automatically be reduced to ~300k routes?
> Te 512k limit refers to FIB in the B/C (base) versions of 6500/7600
> Supervisors and DFCs (for line cards). BXL/CXL versions have FIB for
> 1M IPv4 prefixes.
> You can find more information here:
> And yes, you’re right - no matter how many neighbors you have, the FIB
> will only contain best paths, so it will be closer to 500k entries in
> total rather than N times number of neighbours.

Please correct me if I'm wrong, but if the BGP table contains ~500k 
prefixes, which are then summarized into ~300k routes (RIB), and the FIB 
contains only the "best path" entries from the RIB, wouldn't the FIB be 
at or below 300k?


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