VRF limit in VSS with VS-S720-10G

[pedrocortes]

Hello

I'm planning to implement a VSS system with two 6509 and VS-S720-10G supervisor engines. In technical specifications is said that this card can support up to 1024 VRFs. Is this limit the same when working in VSS?

Many thanks!

[Reza Sharifi]

Hi,

Yes, The number of VRFs is still 1024. Even though you have VSS, technically one sup/chassis is active and the other one is in stand-by mode.

So, the numbers applies to the whole system.

HTH

Reza

[pedrocortes]

Many thanks! This is very helpfull.

[mlgraaf71]

The theoretical limit is 1024 VRFs, but are there also figures of a practical limit.
I have the experience with a switch there where too many VRFs in combination with VLAN interfaces. Result all traffic goes through the CPU of the system.

Resulting a very slow system.

Who has practical numbers?

[alexmcdonald87]

Sorry to bring up an old post, but does anyone have an answer about practical VRF limits? I have a VSS with around 220 VRFs and 7304 virtual ports in total (Maximum on a slot is 1478) and any traffic that traverses the VSL seems to go unbelievably slow. Where as traffic that does not traverse the VSL will go full speed.   I was intrigued as to whether we have to many vlans/vrfs for VSS?   Currently running SXI4

[Scott Hodgdon]

Alex,

VRFs are supported in hardware. The system can support up to 1024 VRFs. Any VRFs above 512 are subject to recirculation, which cuts performance for those VRFs in half. The virtual ports should have no effect in forwarding. Improvements were made in SXI1 such that we no longer even display virtual port messages for linecards (see

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/release/notes/overview.html#wp26366 ).

The best practice for VSS is to have all attached devices dual-homed to the VSS to keep traffic off the VSL. Still, if traffic is going across the VSL it should not be experiencing any kind of slowdown as you describe. You should have TAC investigate.

Thanks,
Scott

[alexmcdonald87]

Thanks Scott that is good news, our 6500's are geographically segregated by over 20km and are connected to multiple core switch/routers at both sites, it's not currently feasible to have them dual-homed to all devices.  Anyway to cut the story short, we ended up upgrading to SXJ1 and I haven't seen the issue since. I've also noticed VSS performance is considerably better, the cpu runs lower and response to commands faster.