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Community Member

6500 : Tx Queue Sizes

Hi,

I read that by default there are different Tx Queue Sizes for different queues available.

1. Can we change the Tx Queue Size of Priority Queue ?

2. I guess we can change the Tx Queue Size of Standard Queues by <<wrr-queue bandwidth X Y Z >> command. Plz confirm..

Thx,

GP

3 REPLIES
Hall of Fame Super Silver

Re: 6500 : Tx Queue Sizes

Hello Gaurav,

in C6500 for its high modularity capabilities and default values are linecard model dependent.

However, you should be able to tune them within the allowed range for a specific linecard.

For some linecards there can be even more varations depending if they mount a DFC or not (not sure of this but it can happen)

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/qos.html#wp1665987

and table 41-3

Weighted Round Robin (WRR)-WRR does not explicitly reserve bandwidth for the queues. Instead, the amount of bandwidth assigned to each queue is user configurable. The percentage or weight allocated to a queue defines the amount of bandwidth allocated to the queue.

Hope to help

Giuseppe

Community Member

Re: 6500 : Tx Queue Sizes

say on Sup 10G 3C supervisor port , can we change the TX queue value for Strict Priority class ?

thx

GP

Hall of Fame Super Silver

Re: 6500 : Tx Queue Sizes

Hello Gaurav,

see table 37-2 in following doc

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/qos.html#wp1665987

notice that the queues structure changes if you decide to disable the GE ports on the supervisor linecard

for tx queues the structure is

1p7q4t

1p7q4t indicates the following:

-One strict-priority queue

-Seven standard queues, each with four thresholds, each threshold configurable as either WRED-drop or tail-drop

this should mean that you cannot choice the size of the priority queue

Actually a strict priority queue is served until the queue is empty: this is the meaning of strict priority queue so its size is in some ways less important then in normal queues

Hope to help

Giuseppe

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