What is the Qos Exceed-Action result

[Imran Ahmad]

Guys,

I have setup an outbound QoS as bellow,  but im not sure how the (exceed-action) will operate. ihv policed web-traffic to 200kbps, but i want my web-traffic to be able to use 100% of the link while there is no VPN-TRAFFIC (priority-traffic), but if there is vpn-traffic then it must be throttled to the policed 200kbps speed. so im not sure the bellow config works correct or not. 

policy-map qos

class vpn-traffic

priority percen 40

class web-traffic

police 200000 conform-action transmit exceed-action transmit                  

Can anyone explain me how exceed-action transmit   really works ?    because as i tested it, while i do (exceed-action transmit) then nothing seems to be limited, the traffic graph just goes to its peak and the link is used full....

[Joseph W. Doherty]

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Posting

As configured, your policer will only effectively provide stats.  The exceed action, as defined, just allows the packet to be transmitted.

From what you describe, a desire for conditional policing, don't believe it's possible.

What you can do is use CBWFQ to prioritize to obtain the desired effect.

Something like:

policy-map qos

class vpn-traffic

bandwidth (link capacity less 200k)

class web-traffic

bandwidth 200

[Alessio Andreoli]

everything is possible in Cisco world

you just need to delete policing or shaping.....

Essentially, implementing CBWFQ only, you ensure a minimum of bandwidth to the types of flows you define/are interested to and the rest is working on a best effort model. in your case i would not use the percentage but i would explicitely define the values in kbps and bits of course.

The point is this, if you police or shape you are rate limiting... so you are with two options:

a) what i have suggested - only CBWFQ

b) a very accurate analysis to define a very precise shaping policy

it's your choice

HTH

Alessio

[Alessio Andreoli]

Sorry Imran,

i was forgetting abou your original question...

If in your policy you say "look, if you have up to 10 kbps of data just transmit and if this value exceed transmit" you will not really see anything. the policy you wrote is working fine ecause you kept the same action in both the cases. If you want to test it you need to tell something like

if exceed drop it or change priority

then you will have a drop that you can see because the bandwidth won't go over the 10 kbps (just an example)

http://www.cisco.com/en/US/products/hw/switches/ps646/products_tech_note09186a00800feff5.shtml

read the link above, short and very practical

Alessio