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Question on dynamic interfaces/ssid

panayiotiscy
Level 4
Level 4

Hello All,

as previously read in the forum and documents, the max number of dynamic interfaces can be 512.

Though, has anyone implemented more than 300 dynamic interfaces in conjuction with the same ssid name for each wlan/dynamic interface?

E.G

vlan 2 10.10.2.0/24 ssid: test wlan id:17

vlan 3 10.10.3.0/24 ssid test wlan id: 18

vlan 4 10.10.4.0/24 ssid:test wlan id: 19

Can someone give me some feedback?

Thank you

9 Replies 9

I have never come across a requirement to do such a thing. What is the driver forcing you to do this ?

Dear rasikanayanajith,

thank you for answering.

to give yout he full picture, i have to deploy more than 200> wireless hot spots to different venues, all of them broadcasting the same ssid.

So, either i go with the option 82 or creating a different interface(on wlc)/ vlan (router) for every venue..

Am i looking into the correct direction?

thank you

There are few inputs required to decide what is the best solution for you.


What would be the setup at each of these hotspot locations?  Do you have proper switch & multiple APs at a given location? If so what switch models & what AP models you are going to deploy? What is the type of WAN link/Internet link available at these locations ? How many wireless users (max) will be at a given location ?

Do you want all the wireless users in these locations come to your central office to access internet ? What type of WLC you have at central location ? Is it really critical to give different subnet at each location users ?

Please provide answer to these to advice on this

Rasika

Hi rasikanayanajith,

In responce to your questions, i can only say that we are having a mixture of 1141,3502,1041 access points, joined a wism-2 controller. We do have proper routing and enough bw between then remote sites and all of the wireless user will be accessing the internet from a central router. we do want to controler the user's ip address because it really matters to the authentication part (caught at a web authentication server).

The manuals say that you can create up to 512 interfaces and ssid limiting only to 8 ssid per ap.Though, i would like to make sure that this assumption will roll out without any unpredictive issues!!

any thoughts?

thank you

Hi Panay,

Based on your information this is what I would do.

1. Group these location to manageable size (let's say 20 groups in each group covering 10 locations)

2. Create 20 AP groups (AP-GRP1 to AP-GRP20)

3. Create 20 interface groups (INT-GRP1 to INT-GRP20)

4. Considering number of max users in a single group (covering 10 locations) add sufficient subnets to interface groups. I would keep consistent subnent mask for simplicity & go for /22 if continous IP blocks available. Interface group allow you future scalability even if you want to add more capacity. For example if you require 200 users per location, I would add two dynamic interfaces to given interface group.

5. Create a single WLAN which needs to be advertised across all locations.

6. Map all APs in a group (10 locations) into AP group & map the WLAN with unique interface group1

ie GRP1 -> AP-GRP1->INT-GRP1

   GRP2-> AP-GRP2->INT-GRP2

In this way you will get scalable & managable solution rather having so many dynamic interfaces created on your controller.

Keep in mind sometimes when your create that many VLAN (STP instances) your switches CPU goes high (even in certain switch platforms you cannot create that many vlan instances). So there will be other side effects creating such large number of vlans.

HTH

Rasika

**** Pls rate all useful responses ****

Hello Rasika,

Ok, i keep what you said in mind and i have to test it before deploying.

Also, i wanted to ask: a) is a subnet of /16 bad design idea for the wlc?

b) what if i bring into the design the dhcp option-82 and thus controlling the assigned users ip address?

thank you

a. Never make such a huge broadcast domain ( 65534 host in single broadcast domain ). We have gone upto /21 (or 2046 hosts) max in our production environment for a given wireless subnet.

b.  DHCP Option 82, you have to make sure your DHCP server is fully supported this feature. If you configuring an IOS DHCP server, then again test with the product platform you have, as all commands (ip dhcp class, etc) may not support every platforms. Also in certain wireless scenarios (like guest auto anchoring) this feature may not work.

Here is some information about DHCP option 82 which may help you to understand how it configure.

http://mrncciew.com/2013/05/18/understanding-dhcp-option-82/

HTH

Rasika

**** Pls rate all useful responses ****

Sandeep Choudhary
VIP Alumni
VIP Alumni

HI Panay,

Please visit this :

https://supportforums.cisco.com/thread/2039215

Hope it helps.

Hello Sandee,

Thank you for providing me with this link.

Though it doesnt really apply to our project because the ssd will not have any security. the ssid is open and the authentication is handled by a captive portal. Even if the captive portal can can also handle aaa , though we are not suppose to modify it.

thanks for helping though

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