Critical eye needed....

[jigsaw2026]

Hi there,

I've been asked to implement qos on a router (2800), and as an absolute beginner I was hoping someone would be able to check my config please...

Basic premise is that we need to classify VoIP traffic as highest, then Telnet and RDP, then all else:

#Set ACL to capture all priority traffic

Ip access-list extended priority

Permit tcp any any eq 3389

Permit tcp any any eq 23

Deny ip any any

#Set traffic to be grouped

Class-map match-all critical

Match protocol rtp

Class-map match-all priority

Match access-group priority

Class-map match-all default

Match ip dscp default

#Classify inbound traffic

policy-map classify-traffic

class critical

set ip dscp ef

class priority

set ip dscp af31

class default

set ip dscp default

#Set outbound queue priority

policy-map queue-on-dscp

class critical

priority percent 50

class priority

bandwidth percent 40

class default

fair queue

random-detect dscp-based

#Assign inbound classification

Interface fa2/0/2

Service-policy input classify-traffic

#Assign outbound queuing

Interface s0/0

Service-policy output queue-on-dscp

My feeling is that I've got one step too many in there...do I really need to dscp classify on ingress when I'm egress queuing based on my class maps? And is this correct, or am I way off the mark?!

Any contstuctive advice would be most appreciated.

Thanks

J2026

[Aaron Harrison · Accepted solution]

Hi

If your QoS policy map matches on protocol/acces s list etc, then you don't need to classify on ingress.

You could classify on ingress (in which case your policy map would mark traffic with a DSCP value) and then use these markings in your QoS policy if you wanted... but this is just overcomplicating it.

I'd just use the outbound policy.

Regards

Aaron

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[jigsaw2026]

Thanks alot Aaron, that's confirmed what I was thinking.