01-03-2007 05:36 AM - edited 03-03-2019 03:13 PM
Hello!
I have the following output policy on a Serial interface:
class-map match-all VoiceSignaling3
description --= CCM 4.1 uses CS3 =--
match dscp cs3
class-map match-all Voice3
match dscp ef
policy-map L3-to-L2
description --= LAN COS setting based on DSCP =--
class VoiceSignaling3
set cos 3
class Voice3
set cos 5
policy-map WAN512
class VoiceSignaling3
bandwidth 16
class Voice3
priority 96
class class-default
fair-queue
random-detect
If there are a lot of conversations through the interface the delay of the voice traffic can reach even 3000 ms!
During "normal" congestion the LLQ works well.
What can be the source of this problem?
Thanks,
Bela
01-03-2007 06:30 AM
How many calls are you tring to run with this configuration. Depending on the codec you use you may be lucky to get 1. 96k is not a lot of bandwidth. Even using high compression you might get 5 calls.
I also cannot see how you can get delays of 3000ms for voice data. It will either transmit it using low latency or drop it. If you are getting delays then your traffic is mis classified
01-03-2007 07:25 AM
hi!
we use g729 codecs, and only 4 calls are allowed on the leased line.
The problem exests even if there are only one call through this interface.
As you can see, we do the classification with Cos. All switches trust cos from cisco phones, but rewrites the cos from other sources.
Regards,
Bela
01-03-2007 06:33 AM
Hi
LLQ is fine from your end . How abt the reverse from the provider or from the other end . In case if your reverse traffic peaks and no QOS done , then any traffic coming return would be in default queue .
Pls check the other side and configure LLQ for ur Voice traffic to solve the problem.
Hope this helps
regards
vanesh k
01-03-2007 07:20 AM
Hi!
The configuration is simmetric. The high Jitter/delay occures only from the previously sent end of the leased line.
Regards,
Bela
01-03-2007 07:25 AM
Hi
As said by Tim ,Might be your LLQ might be full . Can u give the output of " show policy-map interface s0 " output when u have the problem.
regards
vanesh k
01-03-2007 07:27 AM
Hi!
I try, but this is a rare problem, and only one branch is affected.
Thanks,
Bela
01-03-2007 07:34 AM
hi,
first of all you should check if voice traffic is in the right queue.
you can check this with "sh policy-map int"
and look how high this queue is utilizized or if there are dropped packets when a call is placed.
!
01-03-2007 09:40 AM
Hi!
The voice call are in the right queue, with no drops at all.
Bela
02-20-2007 01:23 AM
sh policy-map interface multilink 1 output class Voice3
Multilink1
Service-policy output: WAN384
Class-map: Voice3 (match-all)
90330 packets, 5545648 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: dscp ef (46)
Queueing
Strict Priority
Output Queue: Conversation 136
Bandwidth 96 (kbps) Burst 2400 (Bytes)
(pkts matched/bytes matched) 90330/2160261
(total drops/bytes drops) 0/0
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