Hi, I am interested to know which layer(s) diffserv, dscp & wrr operate at.
I believe diffserv and dscp are the same thing, though diffserv only has priority bits ranging from 0-7 but dscp extends that to more than 60. However, what I don't know what layer the two operate nor do I know what layer wrr operates at.
If someone could enlighten me it would be much appreciated.
That is exactly right.
Diffserv is QOS technology that applies both on L2 and L3 layers. In case of DSCP it is considered to be a layer 3 feature because it uses TOS byte of the IP header. In case of CoS (class of service), it uses L2 markings. WRR is bandwidth allocation method for various queues (each queue at a time). It can be layer 2 feature on L2 switches (every queue gets certain transmission period), and also can be L3 feature that used by CQ (custom queuing) - one of the queuing methods of the Diffserv models.