These three articles by our Vik Malhi for 3750 (virtually identical to 3560) QoS are invaluable:
http://blog.ipexpert.com/2011/05/16/campus-qos-part-1-classification-and-marking-on-the-catalyst-3750/ http://blog.ipexpert.com/2011/06/06/campus-qos-part-2-ingress-queuing-and-scheduling/ http://blog.ipexpert.com/2011/08/25/campus-qos-part-3-egress-queuing-dropping-and-scheduling/ -- Marko Milivojevic - CCIE #18427 (SP R&S) Senior CCIE Instructor / Managing Partner - IPexpert On Thu, Aug 29, 2013 at 11:28 AM, Brandon Bigelow <[email protected]>wrote: > > > > I was wondering if someone could help me better understand queue mappings. > The below is from the Cisco 3560 QoS guide. > > Configuring the CoS-to-DSCP Map > You use the CoS-to-DSCP map to map CoS values in incoming packets to a > DSCP value that QoS uses internally to represent the priority of the > traffic. > > Configuring the DSCP-to-CoS Map > You use the DSCP-to-CoS map to generate a CoS value, which is used to > select one of the four egress queues. > > If the above is true, why do we need four maps for queues? > > cos-input-q cos-input queue map keyword > cos-output-q cos-output queue map keyword > dscp-input-q dscp-input queue map keyword > dscp-output-q dscp-output queue map keyword > > Wouldn't we only need 2 or 3 since the newly formed CoS forms the map to > egress queue? When would we ever use the dscp-output-q? I assume it all > comes down to what you are trusting but this statement confuses me: > "You use the DSCP-to-CoS map to generate a CoS value, which is used to > select one of the four egress queues. " > > > Thanks for your input > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
