User's Manual

Technical Notes – QoS Features on BES50

Figure 16: BES50GE Extended ACL Rule

Step (2) Bind ACL classification rule to an ingress port

This step binds the ACL classification rule to an ingress port. Traffic classification is carried out at the ingress

port where the incoming IP packets enter the BES50GE switch. All packets that match the classification rule are

considered as belonging to the same traffic stream.

A priority index is assigned to the traffic stream which is

then mapped into one of the 8 CoS value.

Since IP DSCP is a 6 bits value, there are more than 8 different combinations of valid DSCP value. A one-to-

one priority index to CoS mapping limits the egress DSCP marking/remarking to only 8 DSCP values. BES50

defines 16 priority index and a non-configurable Priority Index to CoS mapping, which are used in both QoS

treatment and IP DSCP marking/re-marking.

Unlike BES50FE, Ethernet frame and IP packet marking/re-marking is performed on the egress side of

BES50GE when the Ethernet frame is transmitted.