Printing performance over Wireless - Local Break Out?

Answered Question
Sep 7th, 2010

Hi there,


Have a wireless LAN deployment whereby we have multiple LWAPP (1242AG) at different regional offices connecting over the existing wired network and WAN to a central 5508 WLC.

Different wireless users 'break out' onto various VLAN's off the back of the WLC at the central location and can access all the centralised services fine.

However when they print to a local printer in the office the printing traffic is going to the central site and back again to the printer located next to the user....

Client -> LWAPP -> Wired LAN -> WAN -> Central WLC -> WAN -> Wired LAN -> Printer

Printing performance is terrible due to the latency of going over the WAN to the central WLC and back across the WAN to the printer.

Is there any way that we can 'break out' printer traffic onto a VLAN on the LAN whilst still having the rest going to the WLC?

Cheers

Mike

I have this problem too.
0 votes
Correct Answer by bbxie about 6 years 2 months ago

A HREAP can support both local switched and central switched WLANs in the same time, however a WLAN can't support both local switch and central switch mode in the same time.

So basically you can create two WLANs in the WLC, one for local printing which need to be configured as locally switched, another for internet/email traffic which need to be confgigured as centrally switched. You can then apply these two WLANs into the HREAPs in the remote office, so that local printing traffic will not go through WLC, but the internet/email traffic will be sent to WLC.

If you don't want to use two WLANs for different traffic, then it is out of WLC's capability, you have to use wired method, for example, you can configure a WLAN for local switching, then configure routing in the first hop L3 equipment of the HREAP, so that local printing traffic will be routed to local printer, internet/email traffic will be routed to central site.

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Loading.
Mike Bailey Tue, 09/07/2010 - 22:49

Printers could be on thesame VLAN as the AP if necessary.


We've tried a few different combinations of setup and currently using printers on the Wireless LAN itself (HP LaserJet with Wireless JetDirect) but as we don't allow wireles clients to communicate directly due to our security policy this still goes via the central WLC.

In essence I'm happy to consider any solution although ideally I'd like to hard wire printers to a VLAN (potentially same as AP if necessary) on the wired LAN and somehow keep printing traffic locally on the site.

Cheers

Mike

bbxie Tue, 09/07/2010 - 23:38

You can configure the remote offices' AP as HREAP mode; In WLC, create a WLAN for local printing and configure this WLAN as local switching, so that all the local printing traffic will be switched locally, not go through WAN-->WLC-->WAN, this will greatly improve local printing performance.

Following is a link for HREAP design and deploy detail: http://www.cisco.com/en/US/products/ps6087/products_tech_note09186a0080736123.shtml

Mike Bailey Sun, 10/31/2010 - 11:30

Finally had a chance to properly look into this and am I right in thinking that if you use H-REAP specific WLAN's have to be locally switched or

not.

Hence if you want to print locally you'd have to be on a WLAN which allows local break out and therefore not be able to access central resources via the controller at the same time?

Ideally I want to be able to send all email/internet traffic centrally over the controller, with the ability to print locally at the same time.

Correct Answer
bbxie Sun, 10/31/2010 - 14:46

A HREAP can support both local switched and central switched WLANs in the same time, however a WLAN can't support both local switch and central switch mode in the same time.

So basically you can create two WLANs in the WLC, one for local printing which need to be configured as locally switched, another for internet/email traffic which need to be confgigured as centrally switched. You can then apply these two WLANs into the HREAPs in the remote office, so that local printing traffic will not go through WLC, but the internet/email traffic will be sent to WLC.

If you don't want to use two WLANs for different traffic, then it is out of WLC's capability, you have to use wired method, for example, you can configure a WLAN for local switching, then configure routing in the first hop L3 equipment of the HREAP, so that local printing traffic will be routed to local printer, internet/email traffic will be routed to central site.

janesh_abey Mon, 11/01/2010 - 04:56

Hello Bbxie,

Sorry to jump in but if you go down the path where we configure two WLANs, we will requires 2xSSIDs as well,isn't it?

cheers,

J

bbxie Tue, 11/02/2010 - 15:58

Yes, usually you will need two SSIDs although Cisco doc says that two WLAN profiles can share same SSID in certain circumstances(too many limitations, don't suggest it).

Mike Bailey Mon, 11/01/2010 - 13:29

Thanks, just as I suspected.

Two WLAN one for local break out and one for central traffic.

Will need to think about this further, we're transitting the AP->WLC traffic over another units network (the only connection to the network used by the wireless clients is the WLC) so we can't just route over it natively....

Was originally thinking of a private VLAN on their LAN switches which we could 'break out' the printing into but having clients change between WLAN for printing isn't going to be acceptable to the users I fear.

I'm thinking that it might be possible to create a tunnel over the other units network back to the centre (would need some form of termination point between the networks), use H-REAP to break out onto a LAN and then route over the tunnel for central traffic.


Should work, but more complex and will take a lot more thought and testing to get working.

Thanks again.

Actions

This Discussion