Łukasz Bromirski wrote the following on 6/10/2014 12:15 PM:
Hi Blake,
On 10 Jun 2014, at 19:04, Blake Hudson <blake@ispn.net> 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:
http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-swit...
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? --Blake