Cisco 3750 QOS/COS traffic

Unanswered Question
Sep 1st, 2009
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I currenlty have a Cisco 3750 in my datacentre which has a trunk port to a provider allowing certain VLAN's over (This is my A end) the B end's are encapsualated onto Cisco 2800's (this is a hub and Spoke setup). Now I have multiple VLAN's on my 3750 at Layer 3 for each VLAN that comes over the trunk as I run a dynamic routing protocol with the B end sites. What I have been asked to do is mark certain traffic on the B end and the A end. I can do this easily on the B end but I am unsure how it will work on the A end ( I need to mark VOIP and Cirtix). Can it be done with this setup on the 3750 with this setup?

Any questions or thoughts please let me know.



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ralphcarter Tue, 09/01/2009 - 10:13
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I don't believe you can mark traffic on the outbound on a 3750 switch.

You can trust the trunk interface on the 3750 inbound from the provider so that the switch accepts these dscp/cos markings.

Then perform whatever policy on the inbound from the trunk.

Then on your inbound SVI's on the 3750, you can mark the traffic using access-list.


access-list 110 permit udp any any range 16384 32767

class-map VOIP

match access-group 110

policy-map APPS

class VOIP

set dscp ef

int vlan 100

service-policy input APPS


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