Posted on August 10, 2014 5:55 pm
 |  Asked by Matthew Rivard
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I’m fairly new to your products, and am in the process of trying to configure two of your switches, a DCS-7124s and a DCS-7050q-32q to be enable for iSCSI DCB. 

I’ve been able to successfully follow the first half that sets the priority and enabling the needed lldp commands, as that is clearly spelled out in the Arista-Configuration.pdf file, but where I am having some difficulty is in regards to configuring the bandwith alotments for specific traffic priorities, namely iscsi DCB in this case.  

My goal is to setup 10% alotment to iSCSI traffic priority, and the remainder to everything else.

The needed syntax would be greatly appreciated.

Posted by Richard
Answered on October 6, 2014 3:36 pm

Hi Matthew,

I’m not sure if you already received assistance so I will help with your question. When you employ Datacenter Bridging the method of queue scheduling is strict priority. Strict priority queues are serviced in order of precedence until empty, then the next queue is serviced. This is what helps to ensure that PFC enabled traffic is not dropped.

If you want to limit your iSCSI traffic to 10% you have 2 choices: Apply an ingress policer (7050 only) or apply an egress shaper (7050).

If you use an ingress policer, no back-pressure will be applied via PFC and no pause will be generated. However, if you use an egress queue shaper, once the 10% is met PFC will apply back-pressure via pause.

Rich Whitney

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