3Com SUPERSTACK 3 3250 - IP Port Traffic Classification

50 CHAPTER 6: USING TRAFFIC MANAGEMENT
Figure 12 DSCP Service Level Mapping
Figure 12 illustrates how DiffServ code point (DSCP) service levels are
mapped to the four traffic queues.
IP Port traffic
classification
The Switch supports classification of traffic from legacy devices by
classifying traffic using its destination IP port number.
When an IP packet is transmitted it is always tagged with a source and a
destination IP port number. These numbers represent the type of
application that created the packet and can be used to prioritize traffic
originating from different applications.
The transmitting endstation tags a packet with source and destination
port numbers. When the packet is received, the Switch places the packet
in the queue that corresponds to the destination IP port number of the
packet. If there is no priority set against the IP port number then the
packet will be sent out with the default priority.