ssid to vlan

[john smith]

hi friends,

one ssid can map to how many vlans on wism controllers??

can we map one ssid to multiple vlans ??

in aruba wireless we can map multiple vlans to one ssid but in cisco i did not get any info about that

please tell me if someone knows about this??

many thanks in advance

[Scott Fella · Accepted solution]

You can map one ssid to multiple vlans using AP Groups.  When using AP Groups, you badsically define your ssid and interface mapping and then you place certain AP's in that group.  In the 7.x code, there is a feature called interface groups, in which you can define multiple dynamic interfaces and bundle them into a group.  Then you can assign the ssid to use that interface group.  This will perform a round robin to the selected interfaces you bundled.

Hope this helps.

AP Groups:

http://www.my80211.com/cisco-wlc-labs/2009/3/22/cisco-ap-group-nugget.html

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a008073c723.shtml

Interface Group (Vlan Select):

http://www.cisco.com/en/US/products/ps10315/products_tech_note09186a0080b78900.shtml

[john smith]

thanks for you reply Scott Fella

actually this was the one that i was looking for that we can create multiple dynamic interfaces and bundle them in one group and map that one group to ap group that i defined for that area.

thanks for this good info.

can you plz tell me which code 7.x is exactly supporting to configure a bundle of dynamic interfaces?

n one more thing can you plz tell me if i have 2000 number of users on a floor of building n i created one ap group for that floor than the subnet of that dynamic interface which i am going to map that ssid for those users in ap group

how much can be long and works fine like

i can do this to decrease subnet value like /24 has 254 users and /23 has 510 users and /22 has 1000 users and /21 has more than 2000 users but i think this way network performance will not fine wht you say?

in other sulotion i configure multiple interface an bundle them and map to that ssid what is the best practice please advise ???

thanks in advanse

[Scott Fella]

Any of the 7.x code will work, currently i think the 7.0.116.0 has been the best for me.  If you plan on using both AP Groups and defining an Interface Group with that, then the subnet size is really up to you.  I personally like using the /24 and I have bundled 10 /24 together with no issues.

What you have to understand is, if you have seamless roaming between floors, the device will keep their ip address until they loose connection (coverage issue, reboot, disable/enable wireless).  So if you have a user on the 1st floor and the device connects to an AP in AP Group1, that user will keep its ip address as long as it stays connected.  That user can go up to like the 5th floor and connect to an ap in AP Group5 but will keep its ip address obtained from AP Group1.

Also, if you are using dhcp mac reservations at all, interface groups will not work, because it round robins the dhcp request.

[john smith]

thanks for you reply scott fella

what about that if iuse mac reservation on my external MS DHCP server than interface group will not work there too???

many thanks in advance

[Scott Fella]

If you are using mac reservations on any dhcp server, you will not be able to use interface groups for that SSID.  The reason being, is that the wlc will round robin your defined subnet's.  So if you have three bundled together, lets say vlan 10,11 and 12.  The wlc will place the 1st device in vlan 10, the second device on vlan 11 and the third user on vlan 12.  Then it will place the next device on vlan 10 and so on.  So if a device has a mac reservation on vlan 10, and the wlc put that user on vlan 11 or 12, the deive will get a dhcp address but not one that it is assigned to in vlan 10.

[George Stefanick]

Scott,

I havent used it yet. But doesnt dynamic anchoring for static clients allow this behavior ? Have you play with this ?

http://www.my80211.com/home/2011/5/16/wlc-configuring-dynamic-anchoring-for-clients-with-static-ip.html

[Scott Fella]

Well the clients are not static.. They still request a dhcp address and the dhcp server provides the address if there is a Mac reservation or not. The only way you can get it to work is if your using 802.1x on the SSID and you configure AAA override. If the SSID isn't configure for 802.1x maybe because it's printers, etc that have mac reservation, then dynamic vlan doesn't work. Now why not use a static instead of Mac reservations.... Well some clients just don't want to change.

Sent from my iPhone

[Scott Fella]

George,

That feature would be nice if you can specify the mac address and even import a list of mac address with corresponding static address.

By the way.... You have a great blog.  I actually like to refernce your site to my peers.

[George Stefanick]

I labbed this but never put it in production ... Thanks for the kind comments about the blog. Ive learned a lot from your post ... Keep up the great work!

[john smith]

Thank you Scott fella

i really liked you exapmle of vlan 10 11 & 12

but i have some thing to ask

what about if i have mac reservations for all these vlans 10 11 & 12 in my dhcp server.

since in group interface is working in round robin so ssid which is maped to that grouped interface and users want to connect to

let us say user 1 go to vlan10 user 2 go to vlan 11 and user 3 go to vlan 12 and all of them has mac reservation

and if we configure in dhcp server all these vlans as mac reservation and add user1 user 2 user 3's mac addresses in all

those vlans in dhcp

than also it will not work??

many thanks in advance

[Scott Fella · Accepted solution]

That will work, but most of the time when you use Mac reservation, you need that device to have a specific address. For example, a wireless printer or wireless projector, how would you map a connection to that device on your laptop.

Sent from my iPhone

[john smith]

thank you Scott Fella

actually i have a scenario to add mac addresses of the devices which want to get the ip from dhcp server when it synchronise that its mac is same and present in dhcp mac reservation the device will get the ip address whatever device type is laptop wireless printers projector phone etc etc

thanks you so much for you kind replies and help it really very helped me.

i really appreciate and thank to you

[Scott Fella]

No problem... Glad to help

Sent from my iPhone

[skelley5000]

So would you say interface groups are best used for same location or different locations? If I have 1 SSID that I want to use at many different sites and each site is on a different VLAN.

Using this posting as an example, the floors of each building are on a different VLAN but same SSID, so they are going to use interface groups. Could the same be done with multiple physical buildings that are fiber attached?Each bulding will use the same SSID but different  VLANS?