From: Vincent Mashburn (vmashburn@fedex.com)
Date: Wed Nov 29 2006 - 11:16:25 ART
Actually, the class-default is fifo unless you explicitly configure
fair-queue under the class-default in your policy map.
Vince Mashburn
Sr. Voice / Data Engineer
901-263-5072
CCVP, CCNP
Cisco IP Telephony Support Specialist
Cisco IP Telephony Operations Specialist
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Petr Lapukhov
Sent: Wednesday, November 29, 2006 1:37 AM
To: Kal Han
Cc: Groupstudy; Cisco certification
Subject: Re: QoS questions.
Please, see comments inline:
2006/11/29, Kal Han <calikali2006@gmail.com>:
>
> Hi
>
> Question 1
> ---------------
> When I am want to shape traffic on a frame-relay interface,
> based on dlci - After create a policy-map and apply it on an
> interfaces, should I also enable *"frame-relay traffic-shaping"*
> or is this command only useful when I configure my policy
> using *"map-class frame-relay"* and individually applying these
> class per dlci
> Sorry this could be a dumb question but I didnt understand.
You only need to enable "frame-relay traffic-shaping" for legacy FRTS
configuration, i.e. when you specify CIR/minCIR/Bc/Be whithin
map-class with "frame-relay cir", "frame-relay mincir" etc command.
MQC FRTS, and pure MQC configs do not require this command.
Question 2 : class-default and fair-queue
> ----------------------------------------------------------
> For the class-default, I see there is an option to enable fair-queue.
> Is it not the default ? if not what is the default ?
By default "class-default" uses flow-based WFQ, as per the DocCD. You
may
not observe this with "show policy map", however "show queueing
interface"
gives a clue. By default, WFQ is able to accomodate for 256
conversations.
If you want to change the queue to FIFO, you need to specify the
"bandwidth"
keyword under class-default.
<DocCD>
By default, the class-default class is defined as flow-based WFQ.
However,
configuring the
default class with the bandwidth policy-map class configuration command
disqualifies
the default class as flow-based WFQ.
</DocCD>
Question 3: LLQ Vs custom PQ
> ----------------------------------------------
> If LLQ itself is a priority queue, is the reason for using the
priority
> queuing,
> because priority queuing offers more choices of prioritizing traffic ?
>
> and when I have a priority-list of a particular protocol with a
> *low*priority,
> example:
>
> access-list 10 permit 239.1.1.0 0.0.0.255
>
> priority-list 1 protocol ip *low *list 10
>
> does it mean the rest of the traffic (un-classified default)
> is still* lower* priority than the ip traffic my acl selects ?
The biggest difference between legacy PQ and LLQ is that PQ permits
low-priority queues *starvation*. That is, with LLQ high priority queue
is
policed,
and in contrary, with PQ all queues are served in order - from high to
low,
and
until high has been emptied, no low queues are serverd.
This is the main feature of PQ - it has 4 queues, served in strict
order.
HTH
Thanks
> Kal
>
>
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