RCA THOMSON SpeedTouchTM (Wireless) Business DSL Router - Manual (Page 19)

Chapter 3
Basic QoS Concepts
E-NIT-CTC-20041213-0013 v0.5
17
Precedence values The table below gives the
precedence
values:
Second generation The
Differentiated Service Code Point
is a selector for router's per-hop behaviours.
The fields
ECT
and
CE
are spare bits in the IP header used by Explicit Congestion
Notification (
RFC3168
).
As can be seen, the
DSCP
field supersedes the old
Precedence
field. So the values of
DSCP
provide limited backwards compatibility with
Precedence
.
This leads to notions of
"class"
, each class being the group of DSCPs with the same
Precedence
value. Values within a class would offer similar network services but
with slight differences (used to create different levels of service such as "gold",
"silver" and "bronze").
Precedence Purpose
0 Routine
1 Priority
2 Immediate
3 Flash
4 Flash Override
5 CRITIC/ECP
6 Internetwork Control
7 Network Control
Note that IP Precedence is obsolete and is only implemented to provide
backwards compatibility.
0 1 2 3 4 5 6 7
Differentiated Service Code Point ECT CE