From: Vincent Mashburn (vmashburn@fedex.com)
Date: Wed Nov 29 2006 - 14:06:17 ART
That is interesting. However, it is also interesting that when you
configure class-default, no queuing shows up in the default
configuration in the "show run". However, if you configure
"fair-queue", and do a "show run" fair queue now shows up in the
configuration. This suggests that it is not the default.
Vince Mashburn
Sr. Voice / Data Engineer
901-263-5072
CCVP, CCNP
Cisco IP Telephony Support Specialist
Cisco IP Telephony Operations Specialist
________________________________
From: petrsoft@gmail.com [mailto:petrsoft@gmail.com] On Behalf Of Petr
Lapukhov
Sent: Wednesday, November 29, 2006 10:56 AM
To: Vincent Mashburn
Cc: Kal Han; Groupstudy; Cisco certification
Subject: Re: QoS questions.
This has been a long source of QoS controversy around :)
Actually, DocCD says it's WFQ. let's see if it's true:
-------------------
R1#show policy-map TEST
Policy Map TEST
Class class-default
!
interface FastEthernet0/0
service-policy output TEST
!
R1#show queueing interface fastEthernet 0/0
Interface FastEthernet0/0 queueing strategy: none
so it's FIFO when class-default is configured ALONE within policy-map.
--------------------
Let's add some other class:
R1#show policy-map TEST
Policy Map TEST
Class VOICE
Strict Priority
Bandwidth 10 (%)
Class class-default
R1#show queueing interface fastEthernet 0/0
Interface FastEthernet0/0 queueing strategy: fair
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 65000 kilobits/sec
It's WFQ now, what about the policy-map?
R1#show policy-map interface fastEthernet 0/0
FastEthernet0/0
Service-policy output: TEST
Class-map: VOICE (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp ef
Queueing
Strict Priority
Output Queue: Conversation 264
Bandwidth 10 (%)
Bandwidth 10000 (kbps) Burst 250000 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: class-default (match-any)
156 packets, 18988 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Note that Priority Queue has been allocated conversation number 264 but
there's
nothing said about class-default. Quite confusing!
However, we have to conclude, that conversations 1-256 are actually
allocated for
class-default (who else could claim them?), let's see if we can tune
this:
policy-map TEST
class VOICE
priority percent 10
class class-default
fair-queue 512
R1#show queueing interface fastEthernet 0/0
Interface FastEthernet0/0 queueing strategy: fair
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/512 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 65000 kilobits/sec
Number of conversations is 512 now, and it's the same group of
conversations
that was previously allocated for class-default (only the number was
256)
R1#show policy-map interface fastEthernet 0/0
FastEthernet0/0
Service-policy output: TEST
Class-map: VOICE (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp ef
Queueing
Strict Priority
Output Queue: Conversation 520
Bandwidth 10 (%)
Bandwidth 10000 (kbps) Burst 250000 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: class-default (match-any)
208 packets, 25344 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Flow Based Fair Queueing
Maximum Number of Hashed Queues 512
(total queued/total drops/no-buffer drops) 0/0/0
This time policy-map reflect our changes...
Go figure the truth now :)
HTH
2006/11/29, Vincent Mashburn <vmashburn@fedex.com>:
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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