QOS for service provider

emadehsan · ‎08-19-2007

Hello Dear All,

i have some remote locations ( 3 ones)

they are connectinf to headoffices via cisco 3640 routers,

i want to set precedense for making priority to pass traffic

via class-map , set priority , and policy map

i have implemented this issue.,

any better soluiots?

Pavel Bykov · ‎08-19-2007

It all depends on your needs. If you only need to PRIORITIZE (not reserve bandwidth - that's different} one type of very sensitive traffic (e.g. voice), this will work.

Howerver:

1. small note: IPP is obsolete, use DSCP. Just for the future

2. You need to implement it on both sides

3. If you are a customer of VPN network (e.g. MPLS VPN) with higher access rate than your service, qos will not work. Provider needs to implement it on his CE and PE.

4. It's not going to work well in multiaccess scenarios (ATM, FR, MPLS VPN) because of central point higher speed - you would need to shape traffic for each branch at center router too.

5. This is going to work well on some leased line/other 2nd layer service.

6. You need to classify traffic (based on ACL, NBAR, etc.) or have QoS Trust Domain (passing of markings on switches)

What setup do you have and what are you trying to accomplish?

If it's not Voice, Video, or really high priority communication, I'd suggest using "bandwidth" command instead of "priority"

paolo bevilacqua · ‎08-19-2007

All good sliderv with an observation on point 4:

QoS on ATM / FR works OK when L2 parameters are configured correctly.

For ATM the shaping is done in hardware according to traffic parameters.

For FR it is done is software (or distributed to linecard depending on the platform) again corresponding to the PVC traffic values.

No layer-3 shaping should be ever necessary on ATM or FR unless you are trying to artificially slow down something.

jwdoherty · ‎08-19-2007

"Any better solutions?"

Much may depend on what's your physical topology, what your goals are, and what you've done.

If you can provide additional information, might be able to offer some suggestions or confirm what you've done is as good as it gets on Cisco platforms.