Specifying The Precedence Field; Specifying Differentiated Services Codepoint Marking - Patton electronics SmartNode Series Software Configuration Manual

13 • Link scheduler configuration
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 command specifies the precedence marking applied to packets of the class name. Prece-
dence 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 values 6 and 7 are reserved for network control
packets. Therefore, with the set ip precedence command the values 0 through 5 can be set for priority based on
IP networks or applications.
The no form of this command disables precedence marking.
This procedure describes defining the precedence field
Mode: Source
Command
node (src)[ name ]#set ip precedence value

Specifying differentiated services codepoint marking

Differentiated services enhancements to the Internet protocol are intended to enable scalable service discrimi-
nation in an IP network without the need for per-flow state and signaling at every hop. A variety of services
may be built from a small, well-defined set of building blocks, which are deployed in network nodes. The ser-
vices may be either end-to-end or intra-domain; they include both those that can satisfy quantitative perfor-
mance requirements (e.g., peak bandwidth) and those based on relative performance (e.g. "class"
differentiation). Services can be constructed by a combination of:
• Setting bits in an IP header field at network boundaries (autonomous system boundaries, internal adminis-
trative boundaries, or hosts)
• Using those bits to determine how packets are forwarded by the nodes inside the network
• Conditioning the marked packets at network boundaries in accordance with the requirements or rules of
each service.
The requirements or rules of each service must be set through administrative policy mechanisms, which are
outside the scope of this user guide. A differentiated services-compliant network node includes a classifier that
selects packets based on the value of the DS field, along with buffer management and packet scheduling mech-
anisms capable of delivering the specific packet forwarding treatment indicated by the DS field value. Setting
152
selected class or policy name . Valid values for value are 0, 1, 2, 4,
and 8, as given in
table 9
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.
SmartWare Software Configuration Guide
Purpose
on page 151.
Purpose
Link scheduler configuration task list