Chapter 18 Voice over 3G
LTE5366 Series User’s Guide
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DSCP and Per-Hop Behavior
DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (TOS) field in the IP
header. The DS field contains a 2-bit unused field and a 6-bit DSCP field which can define up to 64
service levels. The following figure illustrates the DS field.
DSCP is backward compatible with the three precedence bits in the ToS octet so that non-DiffServ
compliant, ToS-enabled network device will not conflict with the DSCP mapping.
Figure 86
DiffServ: Differentiated Service Field
The DSCP value determines the forwarding behavior, the PHB (Per-Hop 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.
3.
The LTE5366 does not support DiffServ at the time of writing.
DSCP
(6-bit)
Unused
(2-bit)
