QoS Media Policy on the Acme Packet SBC

When configuring QoS for SIP and RTP on an Acme Packet SBC it is critical to set ToS HEX to correct alues. This is accomplished through a Media Policy.

The first step is to create a Media Policy as shown.


sd4500-02# config t
sd4500-02(configure)# media-manager
sd4500-02(media-manager)# media-policy
sd4500-02(media-policy)# name QoS-Audio

The signaling media-type should be set to message and the proper tos-value is 0×60 (CoS 3, DSCP 24). For RTP the media-type value should be set to audio and the proper tos-value for RTP traffic is 0xb8 (Cos 5, DSCP 46).


media-policy
    name                QoS-Audio
    tos-settings        
        media-type          audio
        media-sub-type      
        tos-value           0xb8
        media-attributes
    tos-settings
        media-type          message
        media-sub-type      sip
        tos-value           0x60
        media-attributes

Setting these values in the Media Policy does not invoke QoS. This is simply a set of instructions of what should be applied to signaling and RTP packets but we need to tell the SBC where to apply it. This is done on a realm.


realm-config
    identifier          Access
    description         Public Facing-Untrusted
    addr-prefix         208.57.21.0/24
    network-interface   m00:226
...
    dns-realm           
    media-policy        QoS-Audio
    media-sec-policy

With the media policy assigned to the realm this answers the question of where to apply QoS so the policy is enforced. Any traffic which passes through this realm will be marked, or re-marked, with the appropriate QoS values.