LLQ Question

Answered Question
Aug 14th, 2007
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I have a config that puzzles me b/c while the policy-map RTP class is matching EF, there is no traffic going into the proper queue:


OIGH-CRR01#sh policy-map interface serial 2/0

Serial2/0


Service-policy output: VOICE_LLQ


Class-map: VOICE_CLASSIFY (match-any)

2446 packets, 156544 bytes

5 minute offered rate 1000 bps, drop rate 0 bps

Match: ip dscp ef (46)

2446 packets, 156544 bytes

5 minute rate 1000 bps

Match: ip dscp cs5 (40)

0 packets, 0 bytes

5 minute rate 0 bps

Queueing

Strict Priority

Output Queue: Conversation 264

Bandwidth 320 (kbps) Burst 8000 (Bytes)

(pkts matched/bytes matched) 0/0

(total drops/bytes drops) 0/0


Class-map: SIGNALING_CLASSIFY (match-any)

381 packets, 21036 bytes

5 minute offered rate 0 bps, drop rate 0 bps

Match: ip dscp af31 (26)

357 packets, 18252 bytes

5 minute rate 0 bps

Match: ip dscp cs3 (24)

24 packets, 2784 bytes

5 minute rate 0 bps

Queueing

Output Queue: Conversation 265

Bandwidth 8 (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)

8393 packets, 1846321 bytes

5 minute offered rate 130000 bps, drop rate 0 bps

Match: any

Queueing

Flow Based Fair Queueing

Maximum Number of Hashed Queues 256

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

exponential weight: 9


class Transmitted Random drop Tail drop Minimum Maximum Mark

pkts/bytes pkts/bytes pkts/bytes thresh thresh prob

0 8353/2270881 0/0 0/0 20 40 1/10

1 0/0 0/0 0/0 22 40 1/10

2 0/0 0/0 0/0 24 40 1/10

3 0/0 0/0 0/0 26 40 1/10

4 0/0 0/0 0/0 28 40 1/10

5 0/0 0/0 0/0 30 40 1/10

6 40/2628 0/0 0/0 32 40 1/10

7 0/0 0/0 0/0 34 40 1/10

rsvp 0/0 0/0 0/0 36 40 1/10



Here's the related config:


class-map match-any VOICE_CLASSIFY

match ip dscp ef

match ip dscp cs5

class-map match-any SIGNALING_CLASSIFY

match ip dscp af31

match ip dscp cs3

!

!

policy-map VOICE_LLQ

class VOICE_CLASSIFY

priority 320

class SIGNALING_CLASSIFY

bandwidth 8

class class-default

fair-queue

random-detect


crypto map 3DES-OIGH-CRR01 10 ipsec-isakmp

description TO-BIMC-EXT01

set peer 206.118.27.33

set transform-set 3DES-SHA

match address 111

qos pre-classify


interface Serial2/0

description DS3 TO BIMC-EXT1

ip address 206.118.27.34 255.255.255.252

dsu bandwidth 44210

crypto map 3DES-OIGH-CRR01

service-policy output VOICE_LLQ



Please Enlighten!




Correct Answer by paolo bevilacqua about 9 years 11 months ago

Hi,


that means you serial 2/0 interface was never congested at the time there were voice calls active. When voice packets are actually given priority due to congestion, then you would see (pkts matched/bytes matched) to increment.


Hope this helps, please rate post if it does!

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Correct Answer
paolo bevilacqua Tue, 08/14/2007 - 07:36
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Hi,


that means you serial 2/0 interface was never congested at the time there were voice calls active. When voice packets are actually given priority due to congestion, then you would see (pkts matched/bytes matched) to increment.


Hope this helps, please rate post if it does!

Aaron Dhiman Tue, 08/14/2007 - 07:40
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I thought the packets would always "pass through" the queue even when there is not congestion. Thanks for clarifying.

paolo bevilacqua Tue, 08/14/2007 - 07:43
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No congestion == no backpressure to form priority queue !


Many people don't consider that.


Thanks for the nice rating and good luck!

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