LWAPP and CAPWAP parallel operation ?

[hakan.topcu]

Hello,

currently we have more than 50 APs running in LWAPP mode (10xx, 113x, etc.), connected on four WLC 4402 controllers (v. 4.2.205.0) with enough licenses. Now we need to implement 1142 APs, which are CAPWAP-only capable. This means, to run the new APs, we would need to upgrade our controllers to 5.2 or higher to support CAPWAP. But that’s a disadvantage to our LWAPP-only infrastructure (10xx APs). Therefore we need a solution, to run LWAPP and CAPWAP in parallel for a longer migration phase.

Therefore my first general question: Does anyone have experiences in running LWAPP and CAPWAP parallel inside a common WLAN infrastructure?

Our plan is to upgrade only two of the four controllers to version 5.2 or higher, and connect the newer APs to these WLCs. The older LWAPP APs would stay on the other two controllers.

Because I can’t find any documentation about this scenario, it would be great to hear, if this has already been tested, or implemented by someone, and what we need to consider.

What happens when moving from an LWAPP AP to a CAPWAP AP and back inside the same VLAN/SSID?

Is roaming still possible? ... definitively not? ... or limited???

And is it generally possible to propagate the same SSID over two different APs?

Another question: What is the difference between the “Mobility Domain” and the “Mobility Group”? As far as I know, you can build multiple Mobility Groups inside a common Mobility Domain and have seamless romaing inside the groups, but also inside the whole domain.

Is it possible to build two Mobility Groups “LWAPP” and “CAPWAP” and put them together in the same Mobility Domain?

Many thanks in advance

Hakan

[Nicolas Darchis · Accepted solution]

Hi,

you're thinking too complex :-)

You can have some of your WLCs running 6.0(or 7) and the others running 4.2. 6 and 7 are compatible with 4.2 in a mobility group.

So I suppose all your 4 WLCs are already in a mobility group, so you just need to upgrade 2 of your WLCs.

Whether the AP is lwapp or capwap, it's really only a business between the AP and its WLC. The roaming is handled by the WLCs and as I mentioned, mobility is supported between 4.2 and 6/7 (forget about 5.x).

So full roaming, no limitation.

Just be aware that there are new features in 6/7 and you can't obviously implement them without compatibility concerns but that's quite obvious.

Nicolas

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[hakan.topcu]

Hello Nicolas,

thanks, this is actual a very useful information and I think we will test this. But anyway, I would like to ask you, if this is an official statement (Is there any cisco document, or compatibility matrix?), or if you have tested this already? Sorry for asking this, but I found different documentations, that do not confirm working roaming between different versions, but only those, that do confirm that versions must or should be the same. Someone else already told me, that roaming between different versions "could" work, but it is very likely, that problems occur. It would be interesting to know about a real working scenario.

http://www.cisco.com/en/US/products/ps6366/products_qanda_item09186a00809a30cc.shtml#qa2

What are the prerequisites for a Mobility Group?

- All WLCs must be configured for the same LWAPP transport mode (Layer 2 or Layer 3).- More stability is observed when the WLCs in the same Mobility Group have the same software version.

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a0080810880.shtml#mobility

Wireless LAN Controller (WLC) Configuration Best Practices

These are the best practices for mobility:

All controllers must run the same version of controller software. The only accepted exception for this rule is a controller that currently runs a 4.2.112.0 as anchor in a Guest Access DMZ controller scenario to controllers that run at least 4.1.185.0

http://www.cisco.com/en/US/customer/docs/wireless/controller/6.0/configuration/guide/c60mobil.html#wp1093659

Cisco Wireless LAN Controller Configuration Guide, Release 6.0

Chapter 12 - Configuring Mobility Groups

- When controllers in the mobility list are running different software releases (such as 4.2, 5.0, 5.1, 5.2, and 6.0), Layer 2 or Layer 3 client roaming is not supported between them. It is supported only between controllers running the same release.

- Guest tunneling works only between controllers running the same software release or between controllers running software release 4.2 and controllers running any later software release (for example, 4.2 to 5.0, 4.2 to 5.1, 4.2 to 5.2, or 4.2 to 6.0). Guest tunneling does not work among controllers running other combinations of software.

Note If you inadvertently configure a controller that is running software release 5.2 or later with a failover controller that is running a different software release (such as 4.2, 5.0, or 5.1), the access point might take a long time to join the failover controller because the access point starts the discovery process in CAPWAP and then changes to LWAPP discovery.

CCNA Wireless Official Exam Certification Guide

http://www.ciscopress.com/bookstore/product.asp?isbn=1587202115

(S. 213)

Understanding Mobility Groups

The following must occur for your controllers to support roaming:

- The controllers need to be in the same mobility domain.

- The controllers need to run the same code version.

- The controllers need to operate in the same LWAPP mode.

- Access control lists (ACL) in the network need to be the same.

- The SSID (WLAN) needs to be the same.

Thanks

Hakan

[Nicolas Darchis · Accepted solution]

I was writing a very long post but then CSC logged me out for some reason and it got lost :-(

So sorry but you'll have the short version this time.

http://www.cisco.com/en/US/docs/wireless/controller/release/notes/crn6_0_188.html#wp593717

This is the true word.

The documents you are pointing are either based on 4.2 (it says it in the beggining of the document) where there was no compatibility with 4.2 and earlier releases or wrong. The config guide of 6.0 seems wrong so I'll take care of having it fixed. The config examples and tech notes are subject to be expired and not always up-to-date. However config guide should always show the truth.

I checked my sayings with development official position and yes roaming is supported between maintenance releases of 4.2 and 6.0 as per the release notes.

Nicolas

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[Nicolas Darchis]

To show I'm really following up, here's the bug id I just filed :-)

CSCtl19606 : WLC 6.0 config guide is wrong about Mobility group compatibility w/ 4.2

[hakan.topcu]

Hello Nicolas,

that's great. I never heard about "Inter-Release Controller Mobility (IRCM)". I think that's exactly I was looking for.

PS: I always write offline and do copy & paste my text, because I also made these experiences with lost text a few times ;-)

Thanks again.

Hakan