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2930 series Changing Qos-Queues Internal traffic templates.

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  • 1.  2930 series Changing Qos-Queues Internal traffic templates.

    Posted Feb 07, 2017 09:24 AM
    change qos queue priority 802.1p in 2930F

    I,m A Collegue of Carlos Called Eduardo. Our idea it,s to Classify  ingress traffic From a router Side Based On DSCP and remarkit into a Dot1p Environment. For the Qos Design of our customer (Mandatory) we need to Classify the following:

    DSCP 56 into a Dot1p 7

    DSCP EF and DSCP CS5 into a Dot1p5.

    The Rest We need to Classify in BE. Dot1p 0.

    And From The user Side We need to clasify Based On Dot1p Environment (Dot1p Trust) with For example PC with Phone.

    From another User side PC With Softphone (That Marks Dscp Traffic) the idea is to Based on DSCP traffic (trust DSCP on port) And try to Treat the traffic with GMB on Trunk links between Switches.

     

    The problem is With Remark Dot1p 5 and 7. These Dot1p Qoues corresponds in GMB to the queue 3 (Dot1p 5) And Queue 4 (Dot1p 7).

     

    We need to Separate This queues in order to Guarantee traffic Queue Dot1p 5 in one queue and Dot1p 7 in another Queue. And Dot1q5 with strict priority.

    And Conservating in the Output trunks the same Dot1p markings.

    With Vlan qos. I will translate the markings into anothers and related for specifications of customer designs it,s impossible to do it.

    Thak you.



  • 2.  RE: 2930 series Changing Qos-Queues Internal traffic templates.

    Posted Feb 09, 2017 12:12 AM

    Well, nobody else is answering, so let me just say this:

    Firstly, DSCP 56 *is* according to the standard IP Prec. 7. So you don't need to classify something that is already tagged. Additionally, this QoS level is by default sent to Queue4 (in a 4-queue model) so again you don't need to do anything.

    Having said that - these values are not designed to be used by user-generated traffic. By default they get sent to the highest priority queue, which is configured just right to ensure that the tiny amount of very important DSCP56-tagged traffic that traverses the network is dealt with properly.
    If your customer thinks they should be using this value and its queue for any other kind of traffic, your customer is badly mistaken. Don't touch the value, and don't touch its queue.

    Secondly, EF & CS5 are similarly by default given the IP Precedence value of 5 and sent to Queue3, so you really don't need to do anything.

    Finally, the only things you need to be doing is:
     - trusting on your Access ports. Trust is by default trusting DSCP. You can't trust both. If your phones are putting the correct IP Prec value on their frames, then they are probably also putting the correct DSCP on their packets, so wanting two different trust models is another bit of silliness from your customer.

     - remarking on ingress the traffic coming from the router - sounds like you don't trust it. the EF, CS5 & 56 packets are already correct, so all you need to do is remark everything else. 

     



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