VSS question

[cowetacoit]

I am planning to implement VSS on two 4506-E Sup 7-E switches. We're currently running HSRP on all of the SVIs. What happens when i run the VSS commands and restart  the switches? Does the HSRP configurations still stay?

Also, would there be any configurations lost on switch 2 after the restart?

[Kyle McKay]

All of the HSRP configuration will remain in place after the VSS conversion.

You would need to manually go in and remove the HSRP configuration while you change the IP address of the SVIs to the IP address previously used by the standby group.

[cowetacoit]

So if i have 100 SVIs on each switch and i configure VSS, the second set of SVIs will be removed automatically and i would just go to the 100 SVIs and remove HSRP?

Would all switchport configurations remain on the second switch?

[Reza Sharifi]

You have to be very careful with this if you are doing this in production, as the conversion will cause outage on the network.

1-When you convert to VSS, you don't need HSRP or VRRP any more, as that is actually one of the benefit of VSS

2-When you convert to VSS all you port numbering will change and that will cause issue and outage for you.  If for example: a port is numbered as gi0/1, this will change to gi1/0/1 and on switch 2 the same port is gi2/0/1.  You would have make these configuration changes manually

HTH

[cowetacoit]

Ok, i understand the HSRP stuff and the outages due to having to reboot the two switches.

So on switch 2 port G4/5. If that changes to G2/4/5 and it is configured as a layer 3 port with IP or even just an access port, will i lose that config and have to reconfigure?

[Steve Krause]

When second switch is converted, rebooted and comes up as the standby then all of the VSS switch-2 interface configs will be blank and the interfaces shut down (except for the VSL links, those are merged automatically).

[cowetacoit]

o wow! Thanks for the information. I'll be sure to build a new config for the newly renumbered ports.

[cowetacoit]

If anyone else is going through the same thing.....I'm going to have to update all of our port channels to different numbers. I used the same numbers on both ends.

[Steve Krause]

I'm confused. By "both ends" do you meen both of the switches which are now going to be a VSS? If so, don't forget you can create a single etherchannel across both chassis once they are a VSS so you don't need both of the etherchannels you had originally (unless they are going to two separate upstream switches). It's one of the biggest advantages of converting.

[cowetacoit]

Well, i had port channel 1 (Layer 2 4506to4506), port channel 2 (Layer 3 4506to4506), port channel 3 and up going to upstream devices. i used the same numbers....for example, port channel 5 was a bundle on 4506-1 going to a blade center, and then on 4506-2 i had another port channel 5 going to another switch.

It's confusing but i understand what will happen.

On 4506-1, will i lose any configuration when the interfaces get renamed to 1/x/x ?

[Steve Krause]

The switch-1 interfaces configs are all converted when you reboot that switch. Then, when you reboot the second switch, from switch-1's perspective it looks like you just plugged in new line-cards

I should also mention that my VSS experience is with 6500's only, I am assuming that the 4500 conversion is similar.