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Honoring DSCP value without turning on QoS

DENNIS WEIKEL
Level 1
Level 1

I'm having an issue with the voice quality because the switch ports are not honoring the DSCP values.  I'm assuming DSCP values are rewritten as packets traverse the LAN. Is there a way of forcing the switch to honor the dscp value without turning on QoS?  

To me the two concepts go hand and hand.  You can't talk about the TOS field without talking about QoS. 

Stated another way, the switch ignores all prioritization unless QoS is first turned on.

Does this sound consistent?

Thanks in advance.

Dennis 

2 Replies 2

royalblues
Level 10
Level 10

If you dont turn on QoS, all the DCSP values are honored by the switch port. If Qos is enabled then either you will haveto trust the DSCP settings received or rewrite them as necessary

Narayan

It appears that when QoS is turned off that all DSCP values are rewritten.

Example, I have four switches that are daisy changed to a router.  The traffic is trusted on the receiving port but at the router I don't see any of the marked traffic.  I'm assming that one of the trunk ports is rewritting the DSCP values.

Tthe following comand is returned on one of the interconnecting switches:

SHOW MLS QOS

QoS is disabled

QoS ip packet dscp rewrite is enabled

This leads to believe that the switch is rewritting the DSCP values because QoS is disable.

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