frame-relay class <>

What is different between these two method:

a. int > frame-relay interface-dlci  < >

                class <>

b. int> frame-relay interface-dlci <>

          frame-relay class < >        


Are they going to do same thing ?




    Hi AndiS,

    Under the DLCI I can only use the class <map-class> command, I have no option as frame-relay class <map-class>:

    R1(config)#int se0/0

    R1(config-if)#encapsulation frame-relay

    R1(config-if)#int se 0/0.100 p

    R1(config-subif)#frame-relay interface-dlci 100


    Frame Relay dlci configuration commands:

      auto           Configure Automation

      class          Assign a mapclass to a dlci

      default        Set a command to its defaults

      exit           Exit from FR dlci configuration mode

      help           Description of the interactive help system

      load-interval  Specify interval for load calculation for a dlci

      no             Negate a command or set its defaults

      vofr           Voice over Frame-Relay


    Frame-relay class is only available under the physical interface itself.

    Anyways, the difference is that when you do it under the interface-dlci using the class command you apply the map-class only to that specific DLCI. When you use the latter method, you apply the map-class to all the DLCIs that are under the physical interface.


    Good luck!

  • Hi 

    Actually, there exist three level at which legacy FRTS can be applied.  If the frame-relay class command is applied on the physical interface, it applies to all VC and any point-to-point or point-to-multipont subinterface will inherit the FRTS parameters applied on the physical interface.

    If the FRTS policy is applied to a point-to-point or point-to-multipont subinterface with the frame-relay class comamnd, the FTRS poilcy is applied to VCs on the subinterface.  When the FRTS policy is applied at the subinterface level, it will override the FTRS policy applied that the physical interface level.

    Finally, the FRTS policy can be applied on a per virtual circuit basis with the class command.  Applying the FRTS policy at the VC level will override any policy that is applied at the physical interface and logical subinterfaces.



  • a. int > frame-relay interface-dlci  < >    ------map-class can be applied only to a perticular dlci

                    class <>

    b. int> frame-relay interface-dlci <>      

              frame-relay class < >  


    Never came across "frame-relay class" under frame-relay interface-dlci in any IOS, which ios is showing this optoin ?

  • Frame-relay class is an interface level command. Eborgard gave a good explanation. More specific command wins if there are multiple. So lets say you have 5 DLCI's and want the same behaviour for 4 of them. Then you could do a frame-relay class on the main interface and then do a frame-relay interface-dlci x

    class DLCI_XXX

    For the one DLCI that needs specific behaviour.

  • I got it now. Thanks for quick and detail explanation !

  • Hi AndiS,

    eborgard already explained very well, one thing to mention:

    a. int > frame-relay interface-dlci  < >

                    class <>

    This applies to particular DLCI, which is available under interface-dlci command


    b. int> frame-relay interface-dlci <>

              frame-relay class < >      

    frame-relay class is available under physical or subinterface (not under dlci configuraiton as  you mentioned) and it applies to all DLCIs.

    Good Luck

  • class-map match-any <traffic>

       match ip dscp af31

    class-map match-all <voip>

       match ip dscp ef


    policy-map CHILD

       class <traffic>

            bandwidth percent x

       class <voip>

            bandwitdh percent y

       class class-default



    Policy-map PARENT

        class class-default

            shape average 64000

            shape adaptive 32000

            service-policy out CHILD


    map-class frame-relay FRTS

        service-policy out PARENT


    int s2/0.12 point-to-point

        frame-relay interface-dlci 100

            class FRTS




    R2#sh policy-map interface s2/0


    R2#sh policy-map interface s2/0.12

     Serial2/0.12: DLCI 100 -


      Service-policy output: PARENT


        Class-map: class-default (match-any)

          213 packets, 17158 bytes

          5 minute offered rate 0 bps, drop rate 0 bps

          Match: any

          Traffic Shaping

               Target/Average   Byte   Sustain   Excess    Interval  Increment

                 Rate           Limit  bits/int  bits/int  (ms)      (bytes)

                64000/64000     2000   8000      8000      125       1000


            Adapt  Queue     Packets   Bytes     Packets   Bytes     Shaping

            Active Depth                         Delayed   Delayed   Active

            BECN   0         212       17078     0         0         no


    1. For point to point link, there's only 1 dcli, so both option give same result, right ?

    2. Why i don't see the CHILD policy, shape BECN = 32000 and Shaping Active = No ?


  • 1. For point to point link, there's only 1 dcli, so both option give same result, right ?

    Yes both will give us same result.

    2. Why i don't see the CHILD policy, shape BECN = 32000 and Shaping Active = No ?

    Shaping is not active because you do not have adequate flow to initiate shaping. child policy should also appearing here. 

  • what i'm missing in the config ? can give me a hint ? 


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