QoS 802.1p mapping on ingress port

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Hi all,

I would like to do a 802.1p marking on the ingress port on the switch, because the end node itself cannot mark 802.1p or DSCP value on its frame/packet.

How I can do this?

BR

Lu
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Zhang Lu

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Posted 3 years ago

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Stephen Williams, Employee

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Official Response
Christoph,

Here is a example.  Lets say your ingress port is 1:1 and you want to add a dot1p value of 4 to all the traffic coming into that port.  This is what you would do.

1. Apply this ACL to port 1:1:

entry replace_dot1p_4{
if match all {
} then {
    permit  ;
    replace-dot1p-value 4  ;

} }

Note: Dot1p is in the 802.1q part of the frame so 802.1q tagged frames will have the dot1p value.  If port 1:1 is untagged it will not work.

Link to GTAC Knowledge Article on this topic
(Edited)
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Stephen Williams, Employee

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Official Response
Zhang,

Yes you can.  You can do this by using an Ingress ACL to add a dscp value based on the diffserv replacement mappings on the switch.  In this example below a DSCP code point of 32 will be added on egress. 

Note:  When you add a new DSCP value on ingress it will not be examined on egress.  But the next switch in line will be able to prioritize the traffic on egress.


1 Apply ACL to your ingress port:

entry replace_DSCP_32 {
if match all {
}
then {
    qosprofile qp5 ;
    replace-dscp  ;
}
}

2. Change the diffserv replacement mappings

Switch# configure diffserv replacement qp5 code-point 32
Switch# show diffserv replacement
QOSProfile->CodePoint mapping:
        QP1 -> 00
        QP5 -> 32
        QP8 -> 56


Hope this helps.
(Edited)