QOS Policy 7206 CT3 T1

[eknell]

I am have issues trying to get QOS working correctly over a Serial Int for a customer of ours. We are doing MGCP over a T1 to an Adtran IAD which is the customer VOIP gateway.

When I do a sho policy-map int f0/0, which is the interface to my core, I keep getting pkts matched 0/0.

Setup is like this:

Adtran 608

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7206-VXR CT3 Serial Int

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Cat6509 (running hybrid mode)

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OSR-7609

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Lucent Class 5

Right now, I am just trying to figure out the issue between my VOIP gateway and the 7206, then I will work my way back. Of course, any advice from the 7206 to my phone switch would help as well.

Attached is what I have provisioned on my 7206 and my Adtran. I appreciate the help.

[paolo bevilacqua]

Hi,

Since you have not specified a "match-any" statement, the class-map wants to match all the conditions. This is evidently not happening.

See the guidelines when configuring multiple match statements at:

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a00808029ea.html

Note: Unless your FE0/0 is congested (check queue length), the service policy there is not going to do anything and you can remove it.

Hope this helps, please rate post if it does!

[eknell]

I apprecaite the help, but doesn't seem to change anything. My pkts matched still seem to show 0/0, like it isn't working. Now correct me if I am wrong, but shouldn't this packet count be going up, if It were correctly matching packets that were being set dscp ef (46) or dscp af31 (26) in the header info? Maybe I am reading this wrong. Maybe my IAD device isn't marking them correctly...I don't know? Can you see anything else wrong with my Class-maps or policy-maps, by chance?

This is what was changed:

class-map match-all voip

match ip precedence 5

match ip rtp 16384 16383

match access-group 105

match ip dscp ef

match input-interface Serial1/1/28:0

match any

class-map match-all voice-signaling

match access-group 106

match ip dscp af31

match any

!

!

policy-map voippolicy

class voip

priority percent 50

class voice-signaling

priority percent 5

class class-default

fair-queue

random-detect dscp-based

Also, you said I don't need this on my F0/0 interface...wouldn't I need this on that interface as well to give priority to voip traffic, considering it is my up link towards my call agent? I do have close to 2 DS3's worth of T1's on the router. Thanks for your help.

[paolo bevilacqua]

Hi,

The thing is that you still have "match-all voip", that should be changed to "match-any". I wouls also reduce the match conditions to the minimum necessary, because these are all additional checks done for each packet, and can affect performance negatively.

I don't think that the Fe0/0 will need service policy, because 100 is more that 90 MBps (theoretical), but if you observe queue to build up on fa0/0, you can retain it. Remember, no congestion, no need for QoS or priority.