Negative Side Effects of Enabling Broadcast Forward on 2504 WLC

[DOUG SMITH]

Can someone give me concrete reasons why we should NOT enable broadcast forwarding to resolve the issues as described below?

We have roughly 85 - 2504 WLCs all running 8.0.120 code scattered across 85 physical sites.  

We have an issue that I have fixed in testing within our IT Department.

The issue is this:  There are devices that we are being asked to introduce into our network that connect via wireless.  

http://www.jprofleetproducts.com/adapters/jpro_dlaplus_wireless.asp

They are devices designed to connect to ECM modules on trucks that our dealerships service.  

We are pre-configuring them centrally to connect to a specific WLAN along with DHCP reservations...they connect and get an IP and are on the network without any issue.  

The problem arises when we fire up some proprietary software that tries to find these devices (via UDP broadcasts) to pull diagnostics information over the wireless network and into the software interface.

I have tried changing the WLAN advanced setting of P2P Blaocking Action: Forward-UpStream....but that did not work.

Ultimately to get the software to work...I enabled the Global setting: Controller\General\Broadcast Forward: Enabled.

Even though this fixed our issue...my concern is impact on network performance as well as any security downsides this may have.

We found a workaround within the proprietary software where if we add the static IP addresses as favorites...we can connect to them...but would like to merely discover them via broadcast to make moves/adds/changes a bit easier to manage for both us and the end users.

I have searched for this answer all over the web and this type of info seems to be hard to come by...any help or insight would be most appreciated.

[Rasika Nayanajith]

Enabling broadcast forwarding could resulting high RF utilization and wireless become unusable if RF utilization is too high (anything above 50% is not good).

This is not recommended at all in large deployment. In your case better to monitor RF utilization of a given site with and without this. 

I would always advise not to enable this if you can find another workaround.

HTH

Rasika

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[Freerk Terpstra]

I agree with Rasika but in addition: What is the exact destination of the UDP packet when you start the discovery within the software? And is my assumption correct that the software and clients are in the same VLAN right now?

I'm asking this questions because maybe we can do something with specific directed broadcast forwarding so that only this packets are being forwarded within the (wireless) network to limit the effect.