Ip Tos / Diffserv - Hirschmann Power MICE User Manual

Traffic control

8.4.3 IP ToS / DiffServ

TYPE of Service
U
The Type of Service field (ToS) in the IP header
already part of the IP protocol from the start, and is used to differentiate
different services in IP networks. Even back then, there were ideas about
differentiated treatment of IP packets, due to the limited bandwidth
available and the unreliable connection paths. Because of the
continuous increase in the available bandwidth, there was no need to
use the ToS field. Only with the real-time requirements of today's
networks has the ToS field become significant again. Selecting the ToS
byte of the IP header enables you to differentiate between different
services. However, this field is not widely used in practice.
Bits 1
0
Precedence
Bits (0-2): IP Precedence Defined
111 - Network Control
110 - Internetwork Control
101 - CRITIC / ECP
100 - Flash Override
011 - Flash
010 - Immediate
001 - Priority
000 - Routine
Fig. 39: ToS field in IP header
Basic - L3P
Release 3.1 06/07
2 3 4
Type of Service
Bits (3-6): Type of Service Defined
0000 - [all normal]
1000 - [minimize delay]
0100 - [maximize throughput]
0010 - [maximize reliability]
0001 - [minimize monetary cost]
(see Fig. 39)
5 6 7
MBZ
8.4 Prioritization
was
Bit (7)
0 - Must be zero
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