LevelOne FCS-7111 User Manual

Page 52

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52 - User's Manual

QoS/DSCP (the DiffServ model)

DSCP-ECN defines QoS at Layer 3 (Network Layer). The Differentiated Services (DiffServ) model is

based on packet marking and router queuing disciplines. The marking is done by adding a field to the

IP header, called the DSCP (Differentiated Services Codepoint). This is a 6-bit field that provides 64

different class IDs. It gives an indication of how a given packet is to be forwarded, known as the Per Hop

Behavior (PHB). The PHB describes a particular service level in terms of bandwidth, queueing theory,

and dropping (discarding the packet) decisions. Routers at each network node classify packets according

to their DSCP value and give them a particular forwarding treatment; for example, how much bandwidth

to reserve for it.

Below are the setting options of DSCP (DiffServ Codepoint). Specify the DSCP value for each application

(0~63).

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