RE: LLQ

The documentation and my testing say otherwise:

"When the device is not congested, the priority class traffic is allowed to
exceed its allocated bandwidth. When the device is congested, the priority
class traffic above the allocated bandwidth is discarded."

http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_n1.html#wp1048
842

Edison Ortiz

Routing and Switching, CCIE # 17943

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Ahmed Elhoussiny
Sent: Tuesday, December 08, 2009 1:19 PM
To: Tony Varriale
Cc: Cisco certification
Subject: Re: LLQ

Dear all,

              if LLQ is used for VOIP, it will get dropped/policed in case

the traffic exceeds the LLQ size.

And this in case there is congestion and same if there is no congestion.`

LLQ got nothin to do with congestion, this is based on IOS & IOS XR

features & also my testing while designing QOS for my Mobile operator.

In some references you may find LLQ congestion aware....but this didn't

successfully being implemented till now...

WHY ?

simply imagine u have an LLQ class with 1 M , and no interface BW

congestion.

VOIP traffic increased to reach 2 M, and no drops cuz of no congestion due

to not used BW on other classes...

SO what if the traffic in other queues increased, and reached its 100 %, now

the LLQ will decrease to reach 1 M, and all VOIP calls will get some packets

dropped which will affect most of VOIP calls...

Hope this might help

Thanks & B.regards

Ahmed Elhoussiny,2x CCIE# 21988 (R&S-SP)

Network Consultant & Cisco Academy Instructor

On Tue, Dec 8, 2009 at 6:54 PM, Tony Varriale
<tvarriale_at_flamboyaninc.com>wrote:

> I thought the priority queue won't use the general bucket when it's over

> its

> defined number? Hence, all packets will get dropped.

>

> tv

>

>

> -----Original Message-----

> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of

> Narbik Kocharians

> Sent: Tuesday, December 08, 2009 10:20 AM

> To: Wouter Prins

> Cc: jack daniels; Cisco certification

> Subject: Re: LLQ

>

> If you like the voice traffic to get 1M and 1M ONLY, then, provide LLQ and

> Police that traffic at the same time. Very common.

>

> On Tue, Dec 8, 2009 at 8:10 AM, Wouter Prins <wp_at_null0.nl> wrote:

>

> > Hello Jack,

> >

> > What do you think would happen to the other traffic if the voice traffic

> > was

> > allowed to burst to 2M in a LLQ?

> >

> > Depending on whether the interface is congested or not, the traffic
would

> > be

> > dropped if it exceeds the bw you specify in the priority command. It's

> sort

> > of a conditional policer. The traffic will not end up in the default

> class.

> >

> > 2009/12/8 jack daniels <jckdaniels12_at_gmail.com>

> >

> > > Hi guys,

> > >

> > > Please help me with the understanding of LLQ -

> > >

> > > If I have a link of 2 MB

> > >

> > > and I reserve 1 MB for VOICE ( LLQ) the if voice exceeds 1 MB will it

> be

> > > droppped or be sent in default class.

> > >

> > >

> > >

> >

> > --

> > Wouter Prins

> > wp_at_null0.nl

> > CCIE #25628

> >

> >

> > Blogs and organic groups at http://www.ccie.net

> >

> > _______________________________________________________________________

> > Subscription information may be found at:

> > http://www.groupstudy.com/list/CCIELab.html

> >

> >

> >

> >

> >

> >

> >

> >

>

>

> --

> Narbik Kocharians

> CCSI#30832, CCIE# 12410 (R&S, SP, Security)

> www.MicronicsTraining.com

> Sr. Technical Instructor

> YES! We take Cisco Learning Credits!

> Training And Remote Racks available

>

>

> Blogs and organic groups at http://www.ccie.net

>

> _______________________________________________________________________

> Subscription information may be found at:

> http://www.groupstudy.com/list/CCIELab.html

>

>

> Blogs and organic groups at http://www.ccie.net

>

> _______________________________________________________________________

> Subscription information may be found at:

> http://www.groupstudy.com/list/CCIELab.html

>

>

>

>

>

>

>

>

--
 
 
Blogs and organic groups at http://www.ccie.net