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QoS on FestEthernet subinterface

syedraheel
Level 1
Level 1

Hi,

We have 2.5 Mbps connection from an ISP at our branch routers (1800 series)with single physical link terminated on FE0 but have two subinterfaces with separate subnets.

I have applied the following policy-map outbount under physical Interface FastEthernet 0. Show poliocymap output is as follows

Policy Map QoS-OUT

   Class Email

     priority 512 (kbps)

   Class SQL

     priority 512 (kbps)

   Class File-Copy

    police cir 1024000 bc 32000

      conform-action transmit

      exceed-action drop

   Class CCTV

    police cir 384000 bc 12000

      conform-action transmit

      exceed-action drop

But it seems that sometimes( not all the time ) the CCTV traffic seems to exceed the 384k and chokes the entire link(2.5 mbps).

I don't seem to understand why is it happening?

4 Replies 4

Joseph W. Doherty
Hall of Fame
Hall of Fame

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that    there's no implied or expressed suitability or fitness for any  purpose.   Information provided is for informational purposes only and  should not be construed as rendering professional advice of any kind.  Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever  (including,   without limitation, damages for loss of use, data or  profit) arising  out of the use or inability to use the posting's  information even if  Author has been advised of the possibility of such  damage.

Posting

Are you sure it's the CCTV traffic that actually matches against the CCTV class that's congesting the link?

From you policy statement, I would be concerned about Email and SQL being placed in LLQ, and class-default traffic; all this without a parent shaper to limit total output to 2.5 Mbps.

What's the service policy stats look like when link is congested?

Thanks Joseph,

Sorry for the delay....

Yes its the CCTV traffic, verfied from Netflow. Couldnt gather the stats of service policy

So you are suggesting to use a parent shaper to limit total output to 2.5 Mbps. Then in child policy can I use the police command? how would I limit the amount of CCTC traffic in the child policy at the same time priorotizing other classes?

BR,

Raheel

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Yes, I am suggesting a parent shaper to limit bandwidth to bandwidth to what's logically available.  Otherwise, existing QoS policy won't engage for prioritization until physical interface congests.  (Existing policers should engage, except for implicit LLQ policers.  This is why I question CCTV is the problem.)

Yes, believe you can use police commands within child policy and you would prioritize as desired.  How?  This would be by making your existing policy the child policy being used by a parent policy with a 2.5 Mbps shaper.

Something like:

Policy Map QoS-OUT

class class-default

  shape 2500000

  service-policy QoS-OUT-child

Policy Map QoS-OUT-child

   Class Email

     priority 512 (kbps)

   Class SQL

     priority 512 (kbps)

   Class File-Copy

    police cir 1024000 bc 32000

      conform-action transmit

      exceed-action drop

   Class CCTV

    police cir 384000 bc 12000

      conform-action transmit

      exceed-action drop

BTW, I'm generally against using policers since they allow otherwise available bandwidth to go unused.  You might find the above revised QoS-OUT policy, without the child policy, may provide even better overall service.

Marwan ALshawi
VIP Alumni
VIP Alumni

also have a look at this link to have better understanding about the concept

https://supportforums.cisco.com/docs/DOC-8373

wish this help

if helpful rate