QOS assistance

Unanswered Question
Feb 22nd, 2010

Hi,

We have a client with 4 sites(SHDSL(878's)) in vrf, and they are having issues with intersite voip.

We have applied egress policy maps on WAN Ints(giving 40% priority to voip device IP's), but ingress traffic is causing problems(users downloading content from internet is consuming all bandwidth - They are wanting us to apply similar qos policies to our PE Ints(Egress), but we are reluctant to do this,as it creates a far too complex/unmanageable PE conf if we are to do this with all clients..

What is the recommended solution here?

Thanks in advance

I have this problem too.
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dbass Tue, 02/23/2010 - 07:05

Configuring a policy on the PE is the only way to restrict/give priority in this situation.  You cannot affect the amount of traffic being transmitted on the PE interface from the CE nor would you want to.

johnelliot6 Tue, 02/23/2010 - 12:38

Thanks - We have clients that require very large acl's for voip/qos, therefore implementing policies for clients on PE would create large/complex config's - Is there a better way to manage this....what do the larger providers do?

We only run 7200's, so would introduced load also be a concern?

dbass Tue, 02/23/2010 - 12:42

The large providers have standard policies and increments to which they can create policies.  That is really the only way of doing it and keeping it managable.

Like they will usually have a 4 or 5 class policy and a 7 or 8 class policy.  Obviously the customer pays more to have QoS capabilities, and additional depending on how much realtime traffic (priority queue) they want.

Edison Ortiz Tue, 02/23/2010 - 12:49

You don't have to implement complex policies at the PE side.

If the customer is properly marking their packets, the PE can implement priority, cbwfq or policing depending upon the agreed QoS markings.

In your case, you mentioned the VoIP support along with internet browsing.


At the customer side, in addition to applying the queueing mechanism on egress - make sure to also mark the packets so when the packet returns the PE can act upon.

At the PE, you would be matching on QoS markings, not on ACLs. For non-business internet browsing, you may consider marking it as CS1 (Scanvenger).

johnelliot6 Tue, 02/23/2010 - 22:03

Thanks very much Edison.

This is what I have now setup:

Egress from 1841(Client has one ethernet service(10Mb), which houses there VOIP PBX):

class-map match-any VOIP
match access-group name VOIP-IP

policy-map childpolicy
class VOIP
  priority percent 30
  set ip dscp ef
class class-default
  fair-queue
policy-map 10mb
class class-default
  shape average 8800000
  service-policy childpolicy

interface FastEthernet0/1
..
service-policy output 10mb


Ingress to Site with 878 from PE:

class-map match-any JLF
match ip dscp ef

policy-map JLF-VOIP
class JLF
priority percent 40
class class-default
  fair-queue

interface ATM1/0.92 point-to-point
..
pvc JLF 11/92
..
  service-policy output JLF-VOIP

dscp ef packets are being matched on PE egress policy - Is the above considered "correct" to ensure that default ingress traffic to CE does not interfere with voip traffic?

Thanks again for your assistance.

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