QOS for a VLAN

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Jul 30th, 2009
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Having no practical experience with QOS I'm not sure where to begin with this.

We have a SAN which currently has 4 dedicated LES 100 links to replicate traffic from SAN1 to SAN2.

I've been asked to investigate the possibility of moving this traffic from on to our 2 LES1000 links which we use to route traffic between our 2 data centres.

To do this the SAN traffic which has its own VLAN will need to have a guaranteed amount of bandwidth across the etherchannel trunk.

Is it possible to give a particular VLAN a guaranteed amount of bandwidth or should I approach this another way.

How easy or difficult would this be to do and can anyone give me some tips on how they would approach this, any help would be very much appreciated.

I've attached a diagram of the proposed set up.

Many Thanks


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Joseph W. Doherty Thu, 07/30/2009 - 04:10
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Since you're using 3750s, one approach might be to tag all your SAN VLAN traffic with an unique DSCP value. Then on your two trunk ports, define a shared bandwidth value for one of the four egress queues that provides the minimum amount of bandwidth you want to guarantee. (BTW, not knowing whether both trunk ports will be used concurrently and equally for your SAN traffic, you may need to insure each trunk port reserves the minimum total bandwidth.)


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