Wireless Access

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Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

VLAN Pool vs VLAN Pooling

Hi All,

 

I'm scratching my head over a few terms I'm come across - on this forum and within the Aruba documentation.

 

A user refers to VLAN pooling in the following thread:

They state that VLAN Pooling is a way to add another block of addresses for your wireless clients.
Until I had read this, I thought that a VLAN Pool did this... and you could add another block of client addresses by creating VLAN Pools and config'ing the VAP to use this pool.
When reading the Aruba documentation VLAN Pools functionality is poorly defined. There's great information on how to configure one, but I can't figure out what it's really designed to do for you.
Can someone help clear this up for me?
Thanks
Aruba Employee
Posts: 664
Registered: ‎04-15-2009

Re: VLAN Pool vs VLAN Pooling

AFAIK, they are the same thing.  A VLAN pool is configured, VLANs are assigned to it and then it is referenced under the Virtual AP profile.  That whole process is reffered to a VLAN pooling.

Aruba Employee
Posts: 571
Registered: ‎04-17-2009

Re: VLAN Pool vs VLAN Pooling

It sounds to me like you are referring to "named vlan pools" as opposed to just adding additional vlans to an VAP.

 

CRG to the rescue:

 

vlan-name
vlan-name <name> [pool]
Description
This command creates a named VLAN on the controller and can enable it as a pool. A named VLAN needs to
be first created to assign one or a pool of VLAN IDs to that name.

 

Then in the VAP config:

 

wlan virtual-ap <profile>

     vlan <vlan>...

 

Where <vlan> = 

The VLAN(s) into which users are placed in order to
obtain an IP address. Enter VLANs as a comma-
separated list of existing VLAN IDs or VLAN names. A
mixture of names and numeric IDs are not allowed.

Thanks,

Zach Jennings
Aruba Employee
Posts: 664
Registered: ‎04-15-2009

Re: VLAN Pool vs VLAN Pooling

True.  Both, however, are considered VLAN pooling.  The nice thing about named VLAN pools is that I can pass back the name from a RADIUS server and have it reference local VLANs.  The pool name is global (pushed from master to lcoals), but the VLANs contained in the pool are actually local.  A VLAN pool named employee can be VLANs 100,101 and 102 in one location and VLANs 200, 201 and 202 in another.

Aruba Employee
Posts: 571
Registered: ‎04-17-2009

Re: VLAN Pool vs VLAN Pooling


olino wrote:

True.  Both, however, are considered VLAN pooling.  The nice thing about named VLAN pools is that I can pass back the name from a RADIUS server and have it reference local VLANs.  The pool name is global (pushed from master to lcoals), but the VLANs contained in the pool are actually local.  A VLAN pool named employee can be VLANs 100,101 and 102 in one location and VLANs 200, 201 and 202 in another.


Huh. That's pretty cool that you can pass back the pool name from the RADIUS server.

Thanks,

Zach Jennings
Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: VLAN Pool vs VLAN Pooling

Ah... now it makes more sense.

 

IMO - The WebUI doesn't make it clear that it's a named pool. Your post helped clear this up. I'll have to cross reference the CRG next time.

 

I've been using the named pool as a global option for awhile now, with local VLANs assigned to local controllers. I didn't realize that you could use it as a RADIUS attribute. Cool tip...

 

Thanks!

Aruba Employee
Posts: 664
Registered: ‎04-15-2009

Re: VLAN Pool vs VLAN Pooling

You can pass back any RADIUS attribute and then have a server derivation rule that says to set the VLAN based on that attribute.  For instance, you can pass back Tunnel-Filter-ID with a value of employee or contractor or guest, have VLAN pools setup called employee or contractor or guest and have a server derivation rule that says if attribute Tunnel-Filter-ID exists, set the VLAN to the value-of.

 

Maybe in a future version of code, Aruba will let us use a VLAN pool in a role... wink, wink...

Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: VLAN Pool vs VLAN Pooling

On a related matter...

 

Are the controllers smart enough to know when a VLAN has reached capacity and then start handing out another VLAN assignment? e.g. how does it know that your DHCP scope for that VLAN is full?

Aruba Employee
Posts: 571
Registered: ‎04-17-2009

Re: VLAN Pool vs VLAN Pooling

It uses a formula in an attempt to balance usage across VLANs. The formula uses the MAC address of the wireless client. Therefore one wireless client will get the same VLAN each time. This helps if you ever need to static an IP on your DHCP server, and the IP is a wireless client. We do that for Xbox game consoles.

Thanks,

Zach Jennings
Aruba Employee
Posts: 664
Registered: ‎04-15-2009

Re: VLAN Pool vs VLAN Pooling

No, the controller doesn't know the size of the DHCP scopes, so it cannot know when they are full.  You have to make sure you have enough addresses in the VLAN(s) to service all your clients (plus some room for unbalanced VLANs since you can't yet specify a round robin balance).

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