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Which QoS Will Take Precedence

hi all,

first of all apologies for my question since i'm not a QoS expert.

i configured both my PE and CE router with QoS and was just thinking may i could just configure it on the PE side.  

could anyone confirm which QoS will take over is it on the PE router, CE router on should be both?

4 REPLIES
Silver

Which QoS Will Take Precedence

Generally speaking QoS is an end to end mechanism. It depends on how it is setup though.

Do you control both the PE and the CPE?

If possible it's better to mark packets at CPE and define the policy at the PE. Policy can be used at the CPE as well, it depends on the platform. I have seen different setups, setups where all the QoS is configured on the CPE and with core facing links having QoS. I have also seen setups where no QoS is done on the CPE, the policy was applied on ES cards in a 7600.

So it depends on the platform but if you expect to have congestion on the LAN (unlikely) then you definitely would need QoS on the CPE side.

Daniel Dib
CCIE #37149

Please rate helpful posts.

Daniel Dib CCIE #37149 Please rate helpful posts.

Re: Which QoS Will Take Precedence

Hello

Just like to add you could also mark/classify and possible police ingress traffic on your LAN facing interface on the CE router and then shape this qos Traffic as it leaves the CE

Your ISP would most probably remark your traffic anyway and you cannot manage what comes back over the wire until it hits your CE router but at least you are managing your Egress CIR rate

You also have a word with your ISP and query them on their QOS sla's

But given that your are managing both CE/PErouters you have control over boths direction as to what can be managed and I would say for egress obvisouly CE and PE at least to shape your link the same at both ends.


Res
Paul

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Super Bronze

Re: Which QoS Will Take Precedence

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Posting

John, I'm unsure what you're really asking.

Often a CE<>PE link has less bandwidth then links on the the other side of the CE and/or PE.  If this is true, then if that link congests, and if such congestion is adverse to transit traffic, then egress QoS, on the CE interface to the PE and on the PE interface to the CE, might be beneficial.

"The QoS Book" calls for QoS end-to-end, but bandwidth bottlenecks is where you generally obtain the most benefit.

Re: Which QoS Will Take Precedence

Sorry wrong post

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
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