6500 HSRP migrate to 6800 VSS

[JDMJeffy84]

Hi Guys,

I want to know your thoughts on this:

Currently I have 2 6500 running as the Core router/ switch with all HSRP and SVIs confgured working no problem.

But, they are due an upgrade EoL...

I'm looking to replace like for like 6800 and I want to introduce VSS.

What options will I be looking at to minimise downtime?

I have thought of adding the new 6800s as a standby HSRP and slowly migrate all servers to the new Core then re-configure them as VSS and decommission old 6500 but this way is time consuming but less Risky!

Any thoughts appreciated!

Thanks

[Pierluigi Torriani]

Hi,

i had a similar situation 1 month ago, when i had to replace 2 x 3750x in hsrp config with 2 4500x with vss. I done the same your question but i choose to configure new 4500x in vss using ip address on svi a bit different and i inserted on network. I created all svi on 4500x as i had on 3750x with a little difference of ip and after that i switched one svi at time removing the ip of hsrp on ald 3750x. In my case i couldn't have downtime becouse 1000 users working on that networks.

i was me on the 4500x to change ip on svi and my colleague on 3750x to remove hsrp config simultaneously.

when you remove hsrp on old switches you only can remove standby xx ip 10.11.12.13 . When finish to migrate all you can clean the config not necessary.

with this situation you migrate one svi at time and you can test the signle inter vlan routing at time.

If you want to configure vss later, will beimpossible to don't have downtime. The switch during the reboot to create vss configuration needs about 4 mins and the switches needs to be rebooted both.

If you need any other info, ask me.

I hope this can help you.

Pier

[sajism220]

Hi TorrianiP ,

In this case, how did you move the access switches or users down links.?

Did you move primary and backup links on one shot or one link at a time.

I have a scenario where I need to migrate HSRP to VSS, as you suggested, I will have same VLAN SVI configured in a new VSS box with different IP from the pool but user GW will be still in HSRP box.

I am planning to do the below

1) Move primary access links to new VSS box1
2) Remove the HSRP IP from OLD core and Configure in the New VSS box
3) Move the Secondary access Uplinks to VSS Box2

Is this plan can be achieved with zero downtime

Any Suggestions.

[Pierluigi Torriani]

Hi,

The steps 1,2&3 are correct. I removed the primary link,  removed the hsrp ip And configured as vss ip. Remenber clear arp to speed up the new arp table. After that the gw will be the vss and move the second link. 

You will have a little bit of downtime ,  2 or 3 ping loss 

[sajism220]

Thanks for the response.

What if we running routing protocol and advertised this HSRP vlan connected and static routes pointed to external network 

When we create the SVI with unused IP in new BOX, how do we advertise the subnet in new vss BOX

There will be IP clash in the network correct ? why coz the same subnet is getting adver by old HSRP BoX.

Or we only need to advertise everything after all the services moved to new box keeping the inter-vlan routing between boxes ?

[glen.grant]

  I agree the easiest way might be to temporarily trunk the 6500 to the new 6800 .  HSRP goes away with vss so I assume your svi on the new box will be the vip address under the new svi on the 6800 .  As previous poster said then just migrate them 1 at a time

unless you are adventuresome and want  to hot cut everything at once!!!   Carefully look over how everything is tied to gether now and what would have to be moved .  You really have to map out every single port if the 6500 is going away and this will be a time consuming process .  Actually we have the same thing coming soon where a 3750 stack is going away and 4500 vss is being reccomended,  a big job for sure...