ASA QOS for Voice traffic

[sathish.cco]

Hi ,

We have a customer requirement that they want to give priority for Voice traffic over the other internet traffic.

they have 6 Mbps internet link. ASA  has 2 interfaces configured, inside and outside. ASA 5510 , s/w 9.1.2.

they hosted their VoIP server on the cloud outside.so, only internet traffic on the outside interface.

their issue is , they face voice call clarity issues during the maximum internet usage which is 6 Mbps.

I configured below to give priority for voice traffic over other internet traffic.

priority-queue outside

class-map voice-class
match dscp ef

policy-map pri-policy
 class voice-class
   priority

policy-map qos-traffic-out
class class-default
  shape average 6000000
    service-policy pri-policy

service-policy qos-traffic-out interface outside

After configuring the above config, their feedback was, receivers are able to hear properly but inside users are still facing the same voice quality issues, now, the customer wants 2 MB to be dedicated for voice and remaining to be allocated for the internet .

Can anyone help me to configure to meet the above requirement OR any other alternatives that we can propose to the customer to solve the problem ?

Appreciate your help...

[Karsten Iwen]

The ASA is not really flexible when it comes to QoS.

If you want to "protect" your voice-traffic you could build a second class for all other internet-traffic and police that to a smaller value then 6 MBit. But policing will drop all traffic over that limit and it has to be retransmitted.

If the problems are there constantly, then you need a second line or a faster line.

[sathish.cco]

Hi Karsten,

Thanks for the reply..

Could you please provide the configurations for your above recommendations. 

The customer doesn't care about the drop of internet traffic.

Does the other end device (CE router) also needs to be configured with the QOS when traffic sending back to the firewall, then only QoS works well here ?

Appreciate any inputs...

Thank you

[Karsten Iwen]

Do you have control over the CE-Router? Then it would be better to configure QoS there. It's likely that this device is having the congestion on the interface and a router typically has more flexibility with QoS.

For the ASA, QoS is shown in the config-guide:

http://www.cisco.com/c/en/us/td/docs/security/asa/asa91/configuration/firewall/asa_91_firewall_config/conns_qos.html#pgfId-1065257

Policing should be applied in both directions.