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New Member

Dual Sup720 and dual chassis

I am upgrading my 6509 chassis with 2 Sup720/MSFC. I am currently running single SupII/MSFC with HSRP between the 2 MSFC. I am a little confused on setting up dual MSFC's. Will the vlan interface IP's be identical on each MSFC in the same chassis? I think I understand the HSRP with the priorities with each vlan interface having a different priority.

Hall of Fame Super Gold

Re: Dual Sup720 and dual chassis

Instead of dual Sup720 in dual Chassis (4 Sup 720 in total), read the following data sheet of the new Sup720 with VSS. With this solution, you need to get only two Sup720 for both chassis.

Data Sheet: Cisco Catalyst 6500 Series Virtual Switching Supervisor Engine 720

Hope this helps.

New Member

Re: Dual Sup720 and dual chassis

I already have the sup720's but I think in order to take advantage of the VSS I would need new line cards that support the feature


Re: Dual Sup720 and dual chassis

The latest iteration of Cisco HA after IOS version 12.2(18)SXF8, I believe, is SSO, which stands for Stateful Switch Over.

SSO, like its predecessor, SRM (Single Router Mode), leveraged a synchronization function to keep the configurations of both MSFCs consistent. The standby MSFC would have the complete startup configuration in its NVRAM, but its interfaces would be down and no neighborships would be established with peer routers. Basically, it was as if there was only one router and the ohter was effectively invisible.

When the standby router came online, it co-opted the WAN interface addresses and established neighbor relationships, and then began converging its routing protocol.

The same is true with SSO today, but with NSF (non-stop forwarding), an NSF-aware peer router will not tear down its neighbor relationships upon switchover of the NSF-enabled switch SUPs.

When the NSF-enabled switch finally brings up its secondary MSFC interfaces and establishes its neighborships with its NSF-aware peers, the routing protocol will populate the RIB, which would be sanity-checked with the old CEF table for consistency and correction, in which stale routes would be purged from the CEF table accordingly.

Now you have the routing protocol and the CEF process full converged.

Moreover, the control plane and the data plane are kept isolated with regard to the failover process. While the control plane reconverges, the data plane continues to forward traffic by utilizing the CEF FIB and adjacency tables that were created on the secondary SUP module pre-failover.



New Member

Re: Dual Sup720 and dual chassis

So with SSO configured the 2 MSFC's in chassis A would have identical configurations except for the standby priorities and chassis B and those 2 MSFC's would have identical configurations except for standby priorities.

Re: Dual Sup720 and dual chassis

Hi mihagen

"Will the vlan interface IP's be identical on each MSFC in the same chassis?"

If you are trying to use MSFC's linecard and use HSRP on same chassis, it won't work, I think.

I recommend to consider other alternatives like "LAG"