VSS - Force 10 to Cisco Migration

[Rajagopal Sivaramakrishnan]

Hi All

We have a pair of Force 10 Core/Distribution switches, which is going to be migrated with a Cisco 6807-XL switch designed for VSS. This is a swap migration, ie - the F10 Core1 switch will be shutdown, and the 6807-1 will be placed in the same rack, since we dont have additional rack space to accomodate for parallel migration.

When we put 6807-1, the Force 10 -2 switch will still be active passing traffic. My question is:

1) can I put the 6807-1 with VSS preconfigured, so that when I replace Force10-2 switch with the 6807 pair, it automatically forms VSS neighborship, and is a part of the cluster ?

2) the above question is crucial, since we have VRRP running on F10, and we plan to do just L3 SVI's (and not HSRP) since the 6807s are in VSS pair. 

3) If I cant put a standalone switch on VSS, the only option is to migrate to HSRP , by shutting down VRRP SVI's and bringing UP the HSRP SVI's in Cisco 6807.

I know STP is another mess during this migration, but Ill worry about it later :)

Regards

Raj

[Jay Lohano]

Hi Raj,

You can most certainly do that. Refer to the document here (under Converting the Chassis to Virtual Switch Mode)

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vss.html#wp1055998

In my opinion, there are two ways to do it.

1. Build both the switches for VSS in the lab/work bench. Make sure VSS pairing is formed. Power them off. Then just rack the primary switch and move across SVIs. When you are ready to mount the second switch, just plug the VSL cables according to the configuration and ensure the secondary switch joins the VSS. This would be my prefered way.

2. Configure only one switch as VSS and migrate SVIs across. Then when you are ready to mount the second switch, just configure it, plus everything proprely and ensure VSS comes up.

Let us know how you go.

-Jay

[Rajagopal Sivaramakrishnan]

Hi Jay

Thanks for the reply. Id probably go with option 1.. are there any gotchas with option 1 ? when breaking the VSS, are there any limits/or timelines when the 1st switch can run without its VSS pair ? I know there isnt any, but have you seen any practical scenarios where are there issues with such migration ?

Thanks again for the points.. very useful... 5 points for sure.. :)

Regards

Raj

[Jay Lohano]

Hi Raj,

You can run the VSS switch without its pair indefinitely. You can look under "Failed Chassis Recover" under the document I mentioned in the first post. It advises the same thing. 

Make sure that the switch priority is configured correctly and the you put your Primary VSS in production first. This is not a restriction or limitation, but just a safe practice. Also, make sure you dont power on the secondary switch without connecting the VSL to primary first. This step is to mainly ensure that you dont run into Dual-Active scenario.

Please mark this question as answered so that others can benefit from this discussion.

Thanks

Jay