QOS for voice data on a Cisco 1841 router

Need to setup QOS on a cisco 1841 router connecting two offices with a full T1 P2P line.  I have users at remote location running citrix and just installed VOIP phone system.  Now I want to setup QOS to give priority for voice data over other network traffic.  What commands do I need to put in the routers. One cisco 1841 router at each end.
kencruzanAsked:
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netnounoursCommented:
It all depends on your P2P connection. In the case of a T1, it will not be CoS but that does not really matter.
The default qeueuing will be FIFO and you do not want that with VoIP.
From a QoS (generic term) prospective,I would recommend to use DiffServ end-to-end that will make your configs simpler. It all depends on your equipment and its capabilities.
I hope that helps.
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netnounoursCommented:
You may want to implement at least LLQ (low latency queueing). Just google it on cisco.com

BTW: I assume that QoS is already configured on your LAN.
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kencruzanAuthor Commented:
No, QoS is not configured on my LAN.  I did hear that with P2P connection it is called CoS.  Is that right?
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cstosgaleCommented:
You will need to use MQC (Modular QoS CLI) to enable LLQ (Low Latency Queuing) In order to do this:-

Make sure the correct bandwith is specified on the interface.

In the interface config for the T1:-
ip nbar protocol-discovery
service-policy voice_pq out

class-map Voice
match protocol rtp voice
class-map Voice_control
match protocol h323
match protocol sip

policy-map voice_pq
class Voice
priority percent 50
class Voice_control
bandwith percent 20

What this does is:-

1. Enable nbar protocol discovery to detect voice packets
2. Set up class maps that categorises voice audio and control packets
3. Set up a policy map that specifies what to doo with this traffic and how much bandwith to guarantee. (The percentages can be tweaked for your environment, but bear in mind that the priority percent percentage will determine the maximum allowed percent for voice traffic).
4. Applies this policy map to the external interface.

Hope this makes sense!
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martinezjrjCommented:
sorry for piggy backing here!!!

I'm also using 1841 and have enabled Qos to prioritize voice, however i'm experiencing choppy and delays in calls.

via the SDM., i'm using the Qos wizard to configure QOS and assiging it to an interface.  What is the difference between using NBAR and DSCP?

if i need to start another thread i will, thanks in advance!!
JM
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