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877 QoS for VoIP over IPSEC


Could someone point me in the right direction.

We have 2 sites with 877 adsl routers connected with IPSEC.

Where do I apply the QoS for SIP traffic between the 2 LANs ?

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Re: 877 QoS for VoIP over IPSEC

Hello Nikolaj,

you should do the following:

mark the VoIP packets with IP precedence 5 using a policy-map applied inbound to the LAN interface

on the ATM interface you can apply a service-policy outbound that provides an LLQ for packets with IP precedence 5.

A better setup for the ATM interface is that of using a two levels policy:

the parent policy-map shape all traffic just below the line rate.

a child policy implements LLQ and CBWFQ for traffic

access-list 111 permit udp lan-subnet lan-wildcard any range 16635 16635

class voip_inbound

match access-group 111

policy-map mark_voip

class voip_inbound

set ip prec 5

policy-map shape_all_traffic

class default

shape peak 2000000 (*)

service-policy out llq-cbwfq

class voice_outbound

match ip prec 5

policy-map llq-cbwfq

class voice_outbound

priority 256 (*)

class class-default


int atm0

service-policy out shape_all_traffic

(*) rates are only placeholders you need to identify the right values for your case

This works also if it is GRE over IPsec and it is based on the fact that the TOS of carried packet is copied to the external header

the command qos-preclassify can help too.

Hope to help


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