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New Member

Roaming issue with different IP subnets

hi All,

Let me explain my scenario first.

I have a client site with 25 WAP in Site A, and 10 WAP in SIte B.

Each WAP is connected to different part of the network and having sufficient overlap.(DIff IP Subnet for Wireless Users)

My previous setup was 2 4404 WLC acting as primary/backup for all the WAP.

All WAP in Local mode

New/Current Setup: 2* 5508

1 WLC in site A, and Backup WLC in site B.

for this setup to work i made all the WAP in Flex mode to support failures when local WLC goes down to work fine.

SSID was changed to Local Switching.

So when user roams from AP1 (10.10.1.0/24) --> AP2 (10.10.2.0/24) the user losts connectivity. its because of Local switching.

In this scenario when a client moves from one AP to another on diff subnet why is it losing access and not retaining the connection.

I changed the SSID Local switching. And enabled Central switching and roaming works and all clients get an IP from same subnet configured on WLC.

Now i want to know what am i missing here. Bothe WLC 1, 2 are in same mobility group (which i am not sure what good it makes as its geographically seperated).

for this scenario to work is Flex-connect with Central switching the right option or am i missing some basics here.

looking forward to hear some suggestions or comments.

Everyone's tags (3)
4 REPLIES
Hall of Fame Super Silver

Roaming issue with different IP subnets

When using FlexConnect in local mode, the user subnet's has to be the same for roaming to occur.  Only when the AP's are in local mode or FlexConnect using Central switching is when you can perform a layer 3 roam.  Since you have a backup WLC, I don't see a need to change from local mode to FlexConnect local switching, since your initial install of the 4400's was designed that way.

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
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Hall of Fame Super Silver

Roaming issue with different IP subnets

The following document, states that layer 3 roaming in local switching is not supported.

http://www.cisco.com/en/US/docs/wireless/controller/7.4/configuration/guides/flexconnect/config_flexconnect_chapter_01.html

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
New Member

Roaming issue with different IP subnets

what are the other constraints in this setup.

I have kept the switch ports as Access only and not Trunk -  Do i need to change this to trunk?

So if understand correctly for a Wireless setup ideal solution always is WLC Primary/Backup in same site and not WLC's in two sites and making them as Prim/Back.

When the Primary/Local WLC fails and WAP's fail to WLC2 - in site B the clients will get an IP from SIte B.

And when its failing back to Site A its still retaining the IP from Site B but still works fine.

Is this normal why its retaining the IP.

if its retaining does it mean the routing happens from local site --> site B --> corporate network?

Cisco Employee

Roaming issue with different IP subnets

if you are using more than one vlan then trunk required.

for flexconnect, it doesn't matter where the prim/back is.

for flexconnect, using 7.0 code gets ip only from local site dhcp server, it is nothing to do with wlc failover.

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