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New Member

1750 and QoS

First let me start off by saying I didn't design, create, or even recommend this network. I have just recently inherited this.

My question is will a 1750 router with Version 12.0(3)T do QoS, if not with that version if I upgrade will it then?

My situation is this. We have a branch office that is connected to our main office via wireless connection, 19 miles. The offices are connected by Cisco 350 Access Bridges. The branch office has been using VoIP for sometime and while using the older AiroNet BR500e wireless bridges it appeared to work normally, as well as expected. Since I've put in the new bridges the connection has not be ad stable as before, sometimes it's real bad and other times it's not. But I need to try and resolve this. I know Cisco doesn't support VoIP in a wireless environment yet so that why I wanted to try and see if I can create a work around with QoS. Technically speaking it's not TRUE VoIP it's more like a displaced dial tone. The phones are normal analog phones connect to the patch panel that connects a Voice card in the 1750, (Please see disclaimer above). Any suggestions would be greatly appreciated.



New Member

Re: 1750 and QoS


You can do LLQ to prioritize your Voice Traffic. LLQ require FRTS (Frame Relay Traffic Shapign).

Sample config will be:

First, Classify the Voice traffic (match it either through the IP addresses or via some IP precedence values)

Class-map match- aname

match access-group x <<<< if using acces lists to classify this traffic

Second, Assign the priority BW you want to reserve

policy-map Voice

class NAME

priority 256 <<<< reserved 256K for voice (just example)

class class-default

fair queue

Third, you simply assign this policy map to the associated frame relay map class.

Configured CIR=MinCIR can prevent the burst which cause the delay sensitive. "no frame relay adaptive shaping" ensure that you never go over the guranteed rate and thus your telco will not drop packets.

map-class frame-relay 512K

no frame-relay adaptive-shaping

frame-relay cir 512000

frame-relay bc 5120

frame-relay be 0

frame-relay mincir 512000

frame-relay fair-queue

frame-relay fragment 640

frame-relay ip rtp priority 16384 16383 200

serivce-policy Voice <<------------------------- apply the policy here.

Here is the URL for your refrence.

Warmest Regards,

Bessie NG

New Member

Re: 1750 and QoS

I am not certain whether 12.0(3) will do CBWFQ or LLQ but it should do older forms of QoS i.e. Custom or Priority queueing. If possible upgrade to a 12.2 version of IOS as this supports all the QoS formats on either an IP or IP Plus flavour dependant on your requirement.