XtendLan XL-EFM404V, User Manual

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The following figure illustrates the DS field:
The DSCP value used to identify 64 levels (2
6
=64) of service determines the forwarding behavior that each packet gets
across the DiffServ network. Based on the marking rule different kinds of traffic can be marked for different priorities
of forwarding. Resources can then be allocated according to the DSCP values and the configured policies.
The following is an illustration about how the bits are used in DSCP field.
Bit 0 Bit 1 Bit 2 Precedence Usage
1 1 1 7
Stays the same(link layer and routing protocol keep
alive)
1 1 0 6 Stays the same(used for IP routing Protocols)
1 0 1 5 Express Forwarding (EF)
1 0 0 4 Class 4
0 1 1 3 Class 3
0 1 0 2 Class 2
0 0 1 1 Class 1
0 0 0 0 Best effort
Bit 3 Bit 4 Bit 5 Usage Meaning
0 -- -- Delay Normal
1 -- -- Delay Low
-- 0 -- Throughput Normal
-- 1 -- Throughput High