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help deciphering QoS config for VoIP

our VoIP provider sent us the following configuration to apply to our ASA to QoS our VoIP traffic. 

 

Can someone break down for me what exactly it is doing?  are both instances of bandwidth in bps representative of the bandwidth I want reserved for VoIP?  Or is one supposed to represent the amount of bandwidth set aside for normal web traffic? or something else?

class-map ESI-voice

match dscp af33 cs5 ef

 

policy-map ESI-priority

class ESI-voice

priority

 

policy-map qos-shaper-general

class class-default

shape average <bandwidth in bps>

 

policy-map qos-realtime-shaper

class class-default

shape average <bandwidth in bps>

service-policy ESI-priority

 

service-policy qos-realtime-shaper interface outside

 

 

Thanks!

1 REPLY 1
VIP Advisor

Re: help deciphering QoS config for VoIP

Let's start with this

policy-map qos-shaper-general

class class-default

shape average

*It is not used anyware so you can take it off*

Other than that ESI-priority matches traffic marked as AF33,CS5,EF and put
it in priority queue but you need to define what is the reserved priority
bandwidth in the same command.

Also very important to make sure that you don't have devices between phones
and ASA which strips marking like a switch otherwise you will never match
the policy (the switch should be configured to trust the markings using MQC
or trust command - if supported)

Then the qos-realtime-shaper shapes the traffic at x amount which should be
the link bandwidth and within that reserves traffic for voice by calling
ESI policy.