Configuring Ip Source Route Option Processing; Figure 15-2 Loose Source Route Option Packet Format - Zte ZXR10 ZSR V2 Configuration Manual (System Management

ZXR10 ZSR V2 Configuration Guide (System Management)

15.2 Configuring IP Source Route Option Processing

Overview
IP allows a source host to specify a path through an IP network in advance. This path
is called a source route. If a source route is specified, the software forwards packets
according to the source route. This function can be used to force a packet to pass a
network along a specified route. By default, the software uses a source route.
An IP data packet contains an options field whose length is variable. The options field is
used for testing and debugging networks. Each option in this field begins with an option
code octet that identifies an option type. Option types are listed below:
l
Loose source route option
l
Strict source route option
The router software checks the IP header options of each packet. If it finds that one of
the options is valid, the software performs corresponding operations. If it finds an invalid
option, the software drops the packet and sends an ICMP parameter-problem packet to
the packet source.
For example, the option code of the loose source route option is 131. Its length is variable,
and is determined by the source. The format is shown in

Figure 15-2 Loose Source Route Option Packet Format

The length field represents the length of the option octet (including the option code, length
and pointer fields). The pointer field points to the source address of the next hop, and the
minimum value is 4 (that is, pointing to the IP address of the first hop). The addresses
following the pointer field are the hops designated by the source. The packet must pass
these hops.
Configuration Commands
To configure the processing of IP source route options, run the following command on the
ZXR10 ZSR V2:
Command
ZXR10(config)#
SJ-20140504150128-007|2014-05-10 (R1.0)
ip source-route
15-4
Figure 15-2.
Function
Enables the ZXR10 ZSR V2 processing of
packets with IP source route options.
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