QoS over radio bridge - with router 871

Unanswered Question
May 22nd, 2008


I've connected two sites witch a radio bridge (non Cisco).

Now I'd like to implement QoS over the radio bridge using a couple of Cisco 800 series routers, 871 should work.

My idea is:

lan -- router -- radio -- radio -- router -- lan

The router are attached to the radio bridge with ethernet cable, 100Mbit FD. The radio bridge reaches 25Mbit for each direction.

If I set the bandwidth of the wan interface of the router to 25Mbit at each end, can this be an optimal solution?

I need absolutely to assign voice traffic do LLQ, the radio bridge should't be aware of QoS, it works only FIFO.

What's your opinion?


I have this problem too.
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amritpatek Wed, 05/28/2008 - 09:10

When you configure QoS on the access point/bridge, you can select specific network traffic, prioritize it, and use congestion-management and congestion-avoidance techniques to provide preferential treatment. Implementing QoS in your wireless LAN makes network performance more predictable and bandwidth utilization more effective. You can create QoS policies and apply the policies to the VLAN configured on your access point/bridge. If you do not use VLANs on your network, you can apply your QoS policies to the access point/bridge's Ethernet and radio ports.

Joseph W. Doherty Wed, 05/28/2008 - 16:10

"If I set the bandwidth of the wan interface of the router to 25Mbit at each end, can this be an optimal solution?"

Depends on how you intend to set the bandwidth. Assuming the 800 series supports hierarchal CBWFQ, you would want something like this:

e.g. (pseudo config - syntax likely incorrect)

class-map match-any LLQ-stuff

match protocol rtp audio


policy-map shape-25Mb

class class-default

shape 25Mbps

service policy my-traffic

policy-map my-traffic

class LLQ-stuff

priority percent #

class class-default


interface fastethernet #

!on interface connected to wireless bridge

service-policy output shape-25Mb


From a router performance sheet, I would be concerned whether an 800 series router could fully drive a 25 Mbps link.


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