TCP/IP Tutorial and Technical Overview - IBM Redbooks

outer A has forwarded the packet to node Y (through router B), router A sends a
redirect message to node X. The format of the redirect message (complete with
IP header) is shown in Figure 9-21.
Figure 9-21 Redirect message format
The fields to note in the message are:
Type 137 (Redirect).
Target address This is address of the router that should be used when
trying to reach node Y.
Destination address Node Y's IP address.
362 TCP/IP Tutorial and Technical Overview
6 Traffic Class Flow Label
Payload Length Next = 58 Hops = 255
Source Address (Router A)
Destination Address (Node X)
Type = 137 Code = 0 Checksum
Reserved = 0
Target Address (Router B)
Destination Address (Node Y)
Opt Type=1 Opt Len=1
Source Link Address (Router B)
Opt Type=4 Opt Length Reserved = 0
Reserved = 0
IP Header and Data