where should I configure QoS: router or Switch?

[kzhou00011]

Hi Expert:

We have ISP MPLS link between office, and QoS was configured on MPLS CE by ISP. For our LAN, there is a Cisco ASA behind MPLS CE, and a Cisco 1921 router between Cisco ASA and Cisco 3560 Switch. A vlan for data and vlan for VoIP configured on Switch. so where I should configure QoS for our VoIP to get the best performance: ASA, router or Switch?

Thanks,

Kevin

[Manish Gogna]

Hi Kevin,

Three important QoS design principles are important when deploying campus QoS policies:

>> Classify and mark applications as close to their sources as technically and administratively feasible.
>> Police unwanted traffic flows as close to their sources as possible.
>> Always perform QoS in hardware rather than software when a choice exists.

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book/QoSDesign.html

Specific configuration example is given here

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-4500-series-switches/69632-configuring-cat-ip-phone.html#backinfo

HTH

Manish

[kzhou00011]

Hi Manish,

Thanks for the info.

I know the basic principles, and the commands to configure QoS. But just not sure I should configure QoS on all devices (ASA, Router and Switch) or just Switch which I already did?

Regards,

Kevin

[Marcelo Morais · Accepted solution]

Hi Kevin,

 you should configured QoS on all equipments, because if you miss the QoS configuration in one of your equipments (QoS disable), then you are going to miss the 'Marking' of that packet.

For L2 QoS Configuration ... check this link: 3750 QoS Configuration.

For QoS Configuration .... check this link: QoS Configuration.

Hope this helps.

[kzhou00011]

Hi Marcelo,

Yes, this is what I want to know.

Thanks a lot,

Kevin