nanog mailing list archives

Re: Per Site QOS policy with Cisco IOS-XE


From: Jason Lester <jlester () wcs k12 va us>
Date: Thu, 9 May 2013 10:55:19 -0400

We had a similar problem years ago with a frame-relay <---> IMA setup.  The
hub end was a multiplexed ATM circuit with PVC's to each site's frame-relay
circuit.  The IMA speed was equal to the aggregate speed of each site's
CIR.  It worked great until all the sites were bursting above CIR.  VoIP
call quality would go really bad when that happened (early mornings
mainly.)  QoS policies could not be maintained between the frame and ATM
sides.

Sprint (support contract on the CPE) and MCI (circuits) engineers finally
decided to run PPP over the native protocols on each end and then apply QoS
to the PPP sessions.  That fixed the problem.  I am not sure if something
like that is possible in your case or not though as I am not familiar with
MPLS.  I tried to find the config, but I no longer have it.  I remember it
used virtual templates, but don't remember the specifics.

Jason


On Thu, May 9, 2013 at 10:40 AM, Wes Tribble <westribble () gmail com> wrote:

Tyler,

Tyler,

I already had a case open with TAC on this issue.  This is what the CCIE
assigned to the case is saying about that type of policy:


Hi Wesley,


Yes, I’m afraid that configuration is not possible. We can only mark or
police traffic on this child policy.



You will see the following message when trying to attach the service-policy
to the interface:



---

ASR10004(config-if)#service-policy output parent_shaper
Cannot attach queuing-based child policy to a non-queuing based class

*This is what I sent to her:*

 So this configuration is not possible?

policy-map parent_shaper
 class class-default
 shape average 100000000 < --- 100Mbps parent shaper.
 service-policy site_shaper

policy-map site_shaper
 class t1_site
  shape average 1536000
  service-policy qos_global
 class multilink_site
  shape average 3072000
  service-policy qos_global
  class class-default
  service-policy qos_global

policy-map qos_global
 class VOICE
  priority percent 25
  set dscp ef
 class AF41
  bandwidth percent 40
  set dscp af41
  queue-limit 1024 packets
 class class-default
  fair-queue
  set dscp af21
  queue-limit 1024 packets

On Thu, May 9, 2013 at 8:33 AM, Tyler Haske <tyler.haske () gmail com> wrote:

 Wes,

The earlier policy doesn't use bandwidth commands, hence, it doesn't
*subscribe* anything. The only thing it does is ensures that individual
sites do not exceed their shaped rate. You could add bandwidth statements
if you wanted to ensure a certain site always is guaranteed a certain
amount of bandwidth from the parent shaper. You can't oversubscribe with
the bandwidth command.


policy-map parent_shaper
 class class-default
  shape average 100000000
   service-policy site_shaper

policy-map site_shaper
 class t1_site
  shape average 1536000
  bandwidth percent 1

   service-policy qos_global
 class multilink_site
  shape average 3072000
  bandwidth percent 2
   service-policy qos_global
 class class-default
  bandwidth percent 97
   service-policy qos_global

policy-map qos_global
 ! ... whatever you want here.

This would make sure that large sites don't stare out small spoke sites
for bandwidth.

 On Thu, May 9, 2013 at 8:58 AM, Wes Tribble <westribble () gmail com>
wrote:

Thanks for the information Tyler, I will have to play around with that
kind of policy in my lab.  What would you suggest if you are
oversubscribing the interface?  With the child policy inheriting the
bandwith of the parent shaper, wouldn't I run out of bandwidth
allocation
before I built all the shapers for all of my 29 sites?






-- 

Jason Lester
Administrator for Instructional Technology
Washington County Public Schools
Tel: 276-739-3060
Fax: 276-628-1893
http://www.wcs.k12.va.us


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