Easy VSS

VSS isn’t the hardest thing in the world to configure, but at times it can be a pain. Cisco must have realized this and came up with a solution called Easy VSS. I first heard of this about a year ago, but recently I spend some quality time with a pair of 4500-X’s and decided to figure it out. Here’s what I found as the easiest way to configure it.

First boot both switches and verify they are running the same code. If they are not, make it so.

Second, connect the switches together with twinax or SFP+’s for the VSL link(s).

I’ll configure the first switch. Note that we create a layer 3 interface. This is strictly for reachability and it will be overwritten so use any IP address scheme you like.

Now we’ll configure the second switch. I changed the hostnames just for clarity.

Now we have to jump back to Switch-1 and configure the Easy portion.

Now for the hardest part. It may take a minute or two, but you should eventually see the other switch with the command below.

Excellent we see the other switch. We now have to select the VSL ports. Cisco’s documentation is incorrect or it has changed. In the documentation it states we can simply type Ten1/1, but that errors out.

I found that a copy and paste from above works every time, so lets do that. The first Te1/1 interface is the VSL link on Switch-1 and the second is on Switch-2.

Next we get some logging information including an error. It does not affect the VSS and can be ignored. The switches will reboot.

Here’s a weird thing, when the switches come up, the VSL ports are shutdown. We can no shut the ports, but the standby VSS switch has to be rebooted again. I could not find a way to have them come up no shutdown so maybe it’s a safety precaution??

Switch-1 will tell us that we need to reload the second switch. Just make sure you no shut the port and save the config before reloading.

We already no shut the port on Switch-2 so now we save the config and reload.

Now we wait for Switch-2 to boot and VSS to establish (about 10 minutes total). You should start to see messages stating they are sync’ing.

Once that is complete I add the redundant VSL links to the port channels.

Everything looks good. Below is some testing of removing the VSL links and verifying that VSS stays up.



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