qos sfp links

Unanswered Question
Jan 25th, 2008
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Hi everyone,

I have opened a conversation an 01/17/08 (SFP performance) and I found the problem myslef.

When I configure qos globally of my 3560 (mls qos), the performance of fiber link (SFP's) ist very bad.

But I don't understand why is it so.

QoS on the interfaces is disabled, QoS maps are default. Why is the performance over fiber bad when QoS is globally enabled????? Is it a bug ????

Thank's René

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vinerichard Fri, 01/25/2008 - 04:25
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Hi Rene,

I have just posted a message asking for help and I think this maybe linked. Could you expand on your solution for the interfaces? Did you just turn QoS off?

I too have enabled mls globally and configured mls qos trust dscp and auto qos voip trust on each SFP gigabit uplink. I also have an etherchannel configured on my uplinks.



renekrueger Fri, 01/25/2008 - 05:31
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Hi Richard,

on my 3560 there is a trunk (Gi0/1)via SFP when I configure "mls qos" then the performance over the trunk is to decrease. The same test, a trunk over the Cupper-Port (fa0/1)the performance is fine. There is no more qos configured (trust dscp, auto qos, ..), only globally enabled.

I don't need qos.

But in last time I've analyzed a performance problem on a switch. The result was the global qos configuration on a switch. I tested over cupper and fiber and the problem was on fiber only. I turned qos off and thats fine. But I don't understand why is it so?

Thank's René


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