Specifying The Precedence Field; Specifying Differentiated Services Codepoint (Dscp) Marking; Tos Values And Their Meaning - Patton electronics SmartNode Series Software Configuration Manual

SmartWare Software Configuration Guide
The type-of-service (TOS) byte in an IP header specifies precedence (priority) and type of service (RFC791,
RFC1349). The precedence field is defined by the first three bits and supports eight levels of priority. The next
four bits—which are set by the
TOS Value SmartWare Value
1000
0100
0010
0001
0000
Historically those bits had distinct meanings but since they were never consistently applied routers will ignore
them by default. Nevertheless you can configure your routers to handle specific TOS values and SmartWare
allows you to inspect the TOS value in the ACL rules and to modify the TOS value with the link scheduler
ip tos command.
Mode: Source
Command
node(src)[name]#set ip tos value Defines the type-of-service (TOS) value applied to packets of for the
Specifying the precedence field
The
set ip precedence
cedence and DSCP markings cannot be used at the same time.
The type-of-service (TOS) byte in an IP header specifies precedence (priority) and type of service (RFC791,
RFC1349). The precedence field is defined by the first three bits and supports eight levels of priority. The low-
est priority is assigned to 0 and the highest priority is 7.
The form of this command disables precedence marking.
no
Mode: Source
Command
node(src)[name]#set ip precedence value

Specifying differentiated services codepoint (DSCP) marking

Differentiated services enhancements to the Internet protocol are intended to enable the handling of "traffic-
classes" throughout the Internet. In this context the IP header TOS field is interpreted as something like a
Link scheduler configuration task list
command—determine the type-of-service (TOS).
set ip tos
Table 5. TOS values and their meaning
8 Minimize delay.
4 Maximize throughput.
2 Maximizes reliability.
1 Minimize monetary costs.
0 All bits are cleared, normal service, "default TOS."
selected class or policy name. Standard ToT values are 0, 1, 2, 4,
and 8, as given in
15 can be configured.
command specifies the precedence marking applied to packets of the class name. Pre-
13 • Link scheduler configuration
Meaning
Purpose
table 5 on page 161, but any number from 0 to
Purpose
Defines the precedence marking value applied to pack-
ets of for the selected class or policy name. The range
for value is from 0 to 7, but only values from 0 to 5
should be used.
set
161