QoS/Policing CS5/EF

Unanswered Question
Sep 8th, 2010
User Badges:

Hi,


I'm hoping for some assistance on Policing Voice RTP/Signalling traffic on an edge router connecting into an MPLS cloud.


We are connecting VoIP (equipment does not support CAC) in addition to Data (Does not require prioritisation) and require the Voice Signalling (EF) to be prioritised over RTP (CS5).  The problem is that the MPLS cloud has a single queue which prioritises on DSCP 'EF' only.


In laymans terms what I am trying to achieve is as follows..There is 200k of bandwidth to play with at each site.  Ultimately the Signalling traffic has to take priority over Voice, which takes priority over other default traffic.  The signalling traffic is likely to operate at average 20k, but can burst up 165k during synchronisation.  The RTP is likely to average 40k, and burst up to 160k.


An example of what is configured on the Edge Router supplied by an unnamed service provider is as follows:


class-map match-any ef_output

match ip dscp cs5 ef


policy-map Outbound-to-MPLS

class ef_output

  police 200000 2000 2000 conform-action set-dscp-transmit ef exceed-action

set-dscp-transmit ef violate-action drop


I am intending to set this up in a lab environment but with my mediocre skills of QoS was hoping for some help.  If I seperate out the Class maps as in below, this will at least seperate out the CS5 and EF traffic at least at the Edge Router?(Like I say I'm assuming, don't have much experience with policing!)


class-map match-any cs5_output

match ip dscp cs5


policy-map Outbound-to-MPLS

class cs5_output

  police 40000 5000 15000 conform-action set-dscp-transmit ef exceed-action

set-dscp-transmit ef violate-action transfer


class-map match-any ef_output

match ip dscp ef


policy-map Outbound-to-MPLS

class ef_output

  police 20000 5000 19000 conform-action set-dscp-transmit ef exceed-action

set-dscp-transmit ef violate-action transfer


Perhaps I'm way off the mark with assuming the above would go someway to achieving the goal?  As mentioned ultimately what I'm trying to achieve is prioritise in order EF/CS5/Other traffic.  Additionally handle the burst of traffic, then we do burst we are not dropping packets (specifically the signalling which will cause system instability).


Any advice would be greatly appreciated.


Thanks,


Kevin

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
ashok_boin Thu, 09/09/2010 - 02:41
User Badges:
  • Bronze, 100 points or more

Hi Kevin,


Yes, you are right to have 2 different class maps with separate policing parameters for each kind of traffic. As you might be already aware, this will help you out if you have congestion issues b/w edge router to MPLS PE router as both kinds of traffic still traverse in single EF queue in SP MPLS cloud.


Regards...

-Ashok.

Actions

This Discussion