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Webcast-Catalyst9k
New Member

Auto Qos parameters

Why is the reason for thresholds values so big?

For example, on a 3750 in queue 1 auto qos configures 138/3200 buffers for threshold 1 and 138/3200 buffers for theshold 2.

mls qos queue-set output 1 threshold 1 138 138 92 138

I can´t understand no other values, exist a formule, what are the considerations?

3 REPLIES
VIP Super Bronze

Re: Auto Qos parameters

Ariel,

You can use default or change the parameters:

By default, all allocation values are equally mapped among the four queues (25, 25, 25, 25). Each queue has 1/4 of the buffer space.

By default, the WTD thresholds for queues 1, 3, and 4 are set to 100 percent. The thresholds for queue 2 are set to 200 percent.

This example shows how to map a port to queue-set 2. It allocates 40 percent of the buffer space to egress queue 1 and 20 percent to egress queues 2, 3, and 4. It configures the drop thresholds for queue 2 to 40 and 60 percent of the allocated memory, guarantees (reserves) 100 percent of the allocated memory, and configures 200 percent as the maximum memory that this queue can have before packets are dropped:

mls qos queue-set output 2 buffers 40 20 20 20


mls qos queue-set output 2 threshold 2 40 60 100 200
Here is the link:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/
software/release/12.2_25_see/configuration/guide/swqos.html#wp1179728
HTH
Reza
Hall of Fame Super Bronze

Re: Auto Qos parameters

Ariel,

Please refer to this post https://supportforums.cisco.com/message/630774#630774


Regards

Edison

New Member

Re: Auto Qos parameters

thanks,

but  I can´t understand why this values,  this is subjective?, what are the considerations to choose this values or other. I can´t understand why auto qos use value 138  and not other, someone think that ths value is the best, based on what? what should I use?.

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