2 Replies Latest reply on Nov 7, 2013 8:52 AM by noor

    QoS not dropping packets?

    uc1.com New Member

      Who can tell me what's wrong with the following? Here we have an Adtran NetVanta 3400 series, with a client needing to classify and prioritize voice traffic only.

       

      Who can tell me why we have traffic classified & being matched but not dropped?

       

      qos map VOIP 20
        match dscp 46
        match precedence 5
        priority percent 80
      qos map VOIP 21
        match list aclVoIP21
        set dscp 26

       

      interface ppp 1

        description XClient to ISP

        ip address  X.X.X.X  255.255.255.252

        ip access-policy Public

        media-gateway ip primary

        ppp multilink

        max-reserved-bandwidth 90

        qos-policy out UC1VOIP

        no shutdown

        cross-connect 1 t1 1/1 1 ppp 1

        cross-connect 2 t1 1/2 1 ppp 1

       

      ip access-list extended aclVoIP21

        permit udp any  any eq 5060  

        permit tcp any  any eq 5060

       

      Client1#sh qos map int ppp 1

       

      ppp 1

       

        qos-policy out: VOIP

       

         map entry 20

           match IP packets with a DSCP value of 46

           match IP packets with a precedence value of 5

           priority bandwidth: 80 (% of total) 

           burst budget 61223/61425 bytes (current/max)

           packets matched: 7146021, bytes matched: 1445068601

           packets dropped: 0, bytes dropped: 0

           5 minute offered rate 101744 bits/sec, drop rate 0 bits/sec

       

         map entry 21

           match ACL aclVoIP21

           set DSCP value to 26

       

         map entry default

           packets matched: 59083412, bytes matched: 15950232115

           packets dropped: 0, bytes dropped: 0

           5 minute offered rate 1333784 bits/sec, drop rate 0 bits/sec

        • Re: QoS not dropping packets?
          Employee

          uc1.com - Thanks for posting your question on the forum!

           

          Based on your configuration, you have two QoS policies applied to the PPP interface. The first QoS map entry is matching packets with a DSCP value of 46 or IP precedence value of 5 and giving it a priority over 80% of the available bandwidth when the link is in a congested state. The second QoS map entry is matching traffic defined in the ACL "aclVoIP21" and setting the DSCP value of 26.

           

          You will not see any dropped packets unless the PPP link is in a congested state. In other words, traffic that has a DSCP value of 46 or IP precedence value of 5 will be put in a low latency queue that is prioritized above all other user traffic. If no other traffic is present, the queue is allowed to burst up to the interface rate. Otherwise, priority traffic above the specified priority value will be dropped.

           

          More information can be found in the following guide: Configuring QoS in AOS

           

          Please do not hesitate to let us know if you have any questions.

           

          Thanks,

          Noor

          • Re: QoS not dropping packets?
            Employee

            uc1.com -

            I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post to unmark it and select another in its place with the applicable buttons.  If you have any additional information on this that others may benefit from, please come back to this post to provide an update.  If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.


            Thanks,

            Noor