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New Member

how to enable diff-serv on 4503 ?

hi :)

mates I'll really appreciate if someone can help me about enabling diff-serv on 4503 switch.

- we have hosts directly connected to 4503 switches.

- packet priorities are set on the hosts according to rules defined in diff-serv. (bits are set in IP header field as low/high/medium drop)

-4503 switches are expected to forward those pre-set packets according to their priorities.

what configuration should I make on 4503s?

thanks in advance for helping :)


Re: how to enable diff-serv on 4503 ?


There are a lot of things that you will have to do on the switch for using it to implement certain QoS.

Firstly, the marking of the bits in the ip header doesnot tell the switch how to treat them. you will have to configure the switch to treat different values to be treated the way you want.

So you will have to enable Qos globally on the 4500, and then configure the port to "trust" the incoming markings. By default the markings wont be trusted and the switch will over-write them with the default.

you can then map the values to and others if you want, or just leave them a they are. Then you will have to configure the treatement for the different values using queueing/ policing etc.

please refer to the following guide to configure the device for qos, or refer to the config guide of the ios release you are using:



New Member

Re: how to enable diff-serv on 4503 ?

hi niranjan,

tx for your helpful post. I will follow your recommandations.

actually at the moment switch (4503) doesnt forward any packets.

when I connect hosts to an unmanaged switch, packets are forwarded (not in order we want of course) but when I connect same hosts to 4503 it forwards nothing.

tx again for helping

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