QOS on a particular "scenario"

Unanswered Question
Jun 23rd, 2009


I need to implement an QOS policy for the attached scenario.

Couple things to be mentioned:

All the connection to the router goes to a single Gigabit port; there s a trunk with the 3750 neighbor and on that port goes all the traffic in both directions.

interface GigabitEthernet3/1

description Management_class

ip address

no ip unreachables

no ip proxy-arp

ip accounting output-packets



interface GigabitEthernet3/1.101

description Our_company

encapsulation dot1Q 101

ip address BGP_subclass_A.1


interface GigabitEthernet3/1.102

description Clients_Internet

encapsulation dot1Q 102

ip address BGP_subclass_B.1

interface GigabitEthernet3/1.219

description ISP_1

encapsulation dot1Q 219

ip address ISP_1_IP

no ip redirects


interface GigabitEthernet3/1.401

description ISP_2

encapsulation dot1Q 401

ip address ISP_2_IP

no ip redirects


My goal is to prioritize the Internet for RED selected server, which is actually a Linux GW.

Please throw me some hints of how I could do this ? I was thinking to create an ACL to select the traffic which originates from my Linux GW and then use the class_traffic_ACL on a policy map to and apply a priority of 30;

My question is: where to apply the policy map? On the interface or on the sub_interface? Will it really work?

Or is it better to start marking the traffic of interest?

I have this problem too.
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Florin Barhala Fri, 06/26/2009 - 01:43

Here's how I thought:

- mark the traffic from Linux GW with DSCP AF41 (to be mentioned that there's no other marked traffic)

- as I read the marking will not be altered if it runs on L2 trunks, so it will reach my 7609; there I ll create a class map for all the AF 41 traffic and then a policy map to prioritize the traffic.

Two questions:

- how is it better to do the prioritize ? (I remember you that I need this for all the traffic protocols coming from one single IP address) Simply to reserve some BW using bandwidth command or to use priority command?

- where should I apply the service policy ? On the subinterface or on the interface itself?


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