Policy Map Matching Packets Not Prioritizing

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Jan 25th, 2008
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My policy map is looking for the dsc 5 for my Toshiba phone system to prioritize our inter VoIP. Packets are being matched, but not prioritized. I have allotted 384K for voice. The smallest pipe it travels through is 3 Megabit. I can't tell if the voice is needing prioritized, but the phone conversations break up and drop packets. Any ideas of where to look?

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Edison Ortiz Fri, 01/25/2008 - 07:54
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Please post the relevant portion of the config along with the show policy-map interface output.


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Edison.

tom.gabriel Fri, 01/25/2008 - 12:32
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Carbondale_Tower_CSI#sho policy-map interface vlan 107

Vlan107


Service-policy output: voice


Class-map: voice (match-any)

946947 packets, 202646658 bytes

5 minute offered rate 18000 bps, drop rate 0 bps

Match: ip dscp cs5

946947 packets, 202646658 bytes

5 minute rate 18000 bps

Queueing

Output Queue: Conversation 265

Bandwidth 384 (kbps) Max Threshold 64 (packets)

(pkts matched/bytes matched) 0/0

(depth/total drops/no-buffer drops) 0/0/0


Class-map: class-default (match-any)

5754431 packets, 1679667342 bytes

5 minute offered rate 47000 bps, drop rate 0 bps

Match: any

Queueing

Flow Based Fair Queueing

Maximum Number of Hashed Queues 256

--More-- (total queued/total drops/no-buffer drops) 0/0/0



Carbondale_Tower_CSI#sho policy-map voice

Policy Map voice

Class voice

Bandwidth 384 (kbps) Max Threshold 64 (packets)

Class class-default

Flow based Fair Queueing

Bandwidth 0 (kbps) Max Threshold 64 (packets)

Carbondale_Tower_CSI#


Here is my policy-map output and my policy map. My toshiba phone system using dscp of cs5.

Thanks


Edison Ortiz Fri, 01/25/2008 - 12:57
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You aren't using priority (LLQ), you are using bandwidth which is quite different.


Bandwidth only kicks in during congestion and from the policy-map output, you haven't hit congestion. However, you don't want to place voice packets on regular queues as they tend to be dropped on any bursty situation. There is a reserved queue for things like that, it's called the priority queue.


Your policy map should look like this:



policy-map voice

class voice

priority 384

class class-default

.....

.....

....



HTH,


__


Edison.

shiva_ial Fri, 01/25/2008 - 22:09
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hi edison,

how you confirmed from the output

there is no congestion


Edison Ortiz Sat, 01/26/2008 - 07:43
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Bandwidth only kicks in during congestion.


You presented this output where the ACL is being matched (Note the maximum offered is 18kbps).



Class-map: voice (match-any)

946947 packets, 202646658 bytes

5 minute offered rate 18000 bps, drop rate 0 bps

Match: ip dscp cs5

946947 packets, 202646658 bytes

5 minute rate 18000 bps



Now this is the portion where the Queueing kicsk in:



Queueing

Output Queue: Conversation 265

Bandwidth 384 (kbps) Max Threshold 64 (packets)

(pkts matched/bytes matched) 0/0

(depth/total drops/no-buffer drops) 0/0/0



As you see, no packets are being allocated here since there isn't any congestion.


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Edison.



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