Are default queue values on 6500 blade adequate?

Unanswered Question
Jun 7th, 2007

I am using a 6509 with the Ws-X6148A-GE-45AF blade as our access layer and will have an IP phone and PC plugged into each port.

I will be classifying voice traffic DSCP=46, call control as DSCP=24 and everything else DSCP=0 (all data traffic from the PC), with the following cos-dscp map:

mls qos map cos-dscp 0 8 16 24 32 46 48 54

With 'mls qos' enabled globally, will the resulting default queue bandwidth and buffer space and queue cos-map be adequate for what I need?

Here is the output of 'sh queueing int g1/1':

GHQ-6509A-AU-W271B#sh queueing int g1/1

Interface GigabitEthernet1/1 queueing strategy: Weighted Round-Robin

Port QoS is enabled

Trust state: trust DSCP

Extend trust state: not trusted [COS = 0]

Default COS is 0

Queueing Mode In Tx direction: mode-cos

Transmit queues [type = 1p3q8t]:

Queue Id Scheduling Num of thresholds

-----------------------------------------

01 WRR 08

02 WRR 08

03 WRR 08

04 Priority 01

WRR bandwidth ratios: 100[queue 1] 150[queue 2] 200[queue 3]

queue-limit ratios: 50[queue 1] 20[queue 2] 15[queue 3] 15[Pri Queue]

queue tail-drop-thresholds

--------------------------

1 70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

2 70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

3 100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

queue random-detect-min-thresholds

----------------------------------

1 40[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]

2 40[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]

3 70[1] 70[2] 70[3] 70[4] 70[5] 70[6] 70[7] 70[8]

queue random-detect-max-thresholds

----------------------------------

1 70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

2 70[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

3 100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

WRED disabled queues:

queue thresh cos-map

---------------------------------------

1 1 0

1 2 1

1 3

1 4

1 5

1 6

1 7

1 8

2 1 2

2 2 3 4

2 3

2 4

2 5

2 6

2 7

2 8

3 1 6 7

3 2

3 3

3 4

3 5

3 6

3 7

3 8

4 1 5

The default queueing values give queue 1, which will be all the PC data traffic, 50 % of the buffer space and voice traffic 15%.

Does that mean if the interface is a 100mbs interface, and the PC is transferring say 70mbs, that when the traffic reaches over 50mbs in queue 1 packets will begin to be randomly discarded?

Also the default for the priority queue is 15%, which is 15mbs, which is far more than one phone call.

Should I increase the default queue 1 % and decrease the priority queue %, or are the default vaules OK?

It seems that once I get into tweaking and changing the default values, I'll be stepping into some really murky areas and better know what I'm doing - which at this point I don't.

I have this problem too.
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