Client Roaming Across Policy Profile (wireless client vlan-persistant): Enable or disable it?

[Johannes Luther]

Hi wireless pros,

it's me again with a Cat9800 question.

In release 17.3, the following feature was introduced:

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Client Roaming Across Policy Profile

The controller allows seamless roaming between same WLAN associated with different policy profile.

The following command was introduced:

• wireless client vlan-persistant

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Although I don't have a current actual requirement to do seamless roaming between different policy profiles, I cannot guarantee, that this will pop up in the future.

So the question is:

If you have a pure 17.3+ deployment, it won't harm to add "wireless client vlan-persistant" into the default WLC configuration, right? As far as I understood the config guide, the command does not come with any drawbacks like a higher resource usage at the WLC.

Although completely different features, I compare this one with the "fast-ssid-change" feature in AireOS.

By day0 this feature was disabled by default (without knowing exactely why). So typically this is turned on nowadays, even if you don't have clients moving between different SSIDs... but why punishing them if they want to do it?

[Scott Fella]

I don’t know if I would compare it to fast ssid since policy profiles contain many other options. I think this assumes that the only difference would be vlan difference where your subnets are small and you need to grow and don’t want to change anything on the infrastructure side. Or maybe in FlexConnect where you might have different subnets per floor? Cisco has described policy profile as more of an AP Group in AireOS.

[Johannes Luther]

Like I said: "Although completely different features, I compare this one with the "fast-ssid-change" feature in AireOS."

I don't compare these two features from a functional point of view. More from a configuration standpoint:

=> The default value doesn't seem to make any sense (or I cannot think of any sense).

As of today I cannot think of any case why I would need this (fast roaming between different wireless profile policies). However, I don't see any drawback in activating "wireless client vlan-persistent", because obviously it only comes with advantages and no disadvantages. Or am I missing something?

[Scott Fella]

I don’t see why wlans would be using a different policy profile, at least I would have now reason to. I’m not a fan of enabling “things”, because when something breaks, you will never know which “thing” might of broken it. It’s like the same rule of thumb for SSID’s, keep it as simple as you can. That will give you the least amount of headaches.
I only enable “things” if I truly need them. If I was deploying to different customers as an example, I would keep my “trusted” template as simple as possible. It will be a nightmare for a customer to troubleshoot if features are enabled just because it can be. That is my opinion.