From: Devi Mallampalli (Devi.Mallampalli@chubb.com.au)
Date: Sat Dec 04 2004 - 09:34:15 GMT-3
Hi Group,
I was wondering is it possible to make a CQ (with let us say 4 queues ,
queue 1 = FTP , queue 2 = Telnet , queue 3 = dlsw , queue 16 = default)
interoperable with a CBWFQ so that CBWFQ can call any of CQ config
parameters in any way ?
From my understanding , CQ is a legacy way of deploying or manipulating
the " service threshold" a traffic type from default behavior of 20
packets in the queue depth and 1500 bytes of pick up run by the
scheduler on her each pass. And this mechanism I believe is successfully
taken over by CBWFQ algorithm which is more flexible (64 queues as
oppose 16)and can offer better results. And CBWFQ can do almost all of
things CQ does in terms of identifying the traffic types (class-maps)
and deciding what to do with each traffic type (policy map) and then
applying to an interface with a service policy.
So in other words , to me they both are similar algorithms , one a
legacy one and 2nd one is more sophisticated with better control. There
by I think you can not join CQ with CBWFQ in any manner ???
Let me explain you with an example:
B/W on wire = 64k
Ftp to have = 30%
Telnet to have = 20%
Dlsw to have = 10 %
Default to have = rest of B/W.
So with the above info , I can calculate the required byte-count of each
queue with the below formula.
Ftp = 30% of bandwidth to be given = 64 000 / 8 = 8000 bytes * 30/100 =
2400 byte-count , which will go in as "queue-list 1 queue 1 byte-count
2400 limit 100"
telnet = 20% of bandwidth to be given = 64 000 / 8 = 8000 bytes *20/100
= 1600 byte-count , which will go in as queue-list 1 queue 2
byte-count 1600 limit 100
Dlsw = 10%% of bandwidth to be given = 64 000 / 8 = 8000 bytes *
10/100= 800 byte-count , which will go in as "queue-list 1 queue 3
byte-count 800 limit 100"
Default = 40% of bandwidth to be given = 64 000 / 8 = 8000 bytes *
40/100 = 3200 byte-count , which will go in as queue-list 1 queue 16
byte-count 3200 limit 100
And then these queues will then be applied on an interface with a
custom-queue command.
But now my Q is , since we can do the same thing with CBWFQ too with the
following config, am not sure how we can make these 2 algorithms
interoperate (if at all there is a provision/necessity) the above config
of CQ to the below mentioned config of CBWFQ ?
Ip cef
Class-map ftp
Match protocol ftp
Class-map telnet
Match protocol telnet
Class-map dlsw
Match protocol dlsw
Policy-map cbwfq
Class ftp
Bandwidth percent 30
Queue-limit 100
Class telnet
Bandwidth percent 20
Queue-limit 100
Class dlsw
Bandwidth percent 10
Queue-limit 100
Class class-default
Bandwidth percent 40
Interface s0/0
Service-policy output cbwfq
I appreciate any feed back on this subject.
Regards
Devi
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