Unanswered Question
Jan 8th, 2009

Hi, How can we reserver 50% of interface bandwidth with the help of Custom-Queue ?

I have this problem too.
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Giuseppe Larosa Fri, 01/09/2009 - 05:03

Hello Rupesh,

I would use CBWFQ if possible instead of Custom Queueing because it is more flexible.

With custom queueing you configure how many bytes are taken from each defined queue

(note a system queue also exists).

The actual distribution of resources depends also on the average size of packets on each queue:

if a packet can be taken from the queue to be sent on the tx queue of interface it is taken even if there is not enough credit in the token bucket.

So depending on the number of queues and on the average size of packets on each queue a different BW distribution is implemented

if packet is all the same size the ratio is

BW_perc_queue-X = byte-count_queue_x /(sum of all byte counts)

taking into consideration possible different queue sizes need to use

packets serviced at each round

byte_count_queue_X /average_size_queue_x

to compare every queue you need to normalize to max size among all queues


I would use Custom queueing only for legacy traffic (non ip traffic) that cannot be handled with MQC CBWFQ.

Hope to help



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