4.1.3.3 ICMP Messages (original) (raw)

Connected: An Internet Encyclopedia
4.1.3.3 ICMP Messages

Up: Connected: An Internet Encyclopedia
Up: Requests For Comments
Up: RFC 1122
Up: 4. TRANSPORT PROTOCOLS
Up: 4.1 USER DATAGRAM PROTOCOL -- UDP
Up: 4.1.3 SPECIFIC ISSUES

Prev: 4.1.3.2 IP Options
Next: 4.1.3.4 UDP Checksums

4.1.3.3 ICMP Messages

UDP MUST pass to the application layer all ICMP error messages that it receives from the IP layer. Conceptually at least, this may be accomplished with an upcall to the ERROR_REPORT routine (see Section 4.2.4.1).

DISCUSSION:

Note that ICMP error messages resulting from sending a UDP datagram are received asynchronously. A UDP-based application that wants to receive ICMP error messages is responsible for maintaining the state necessary to demultiplex these messages when they arrive; for example, the application may keep a pending receive operation for this purpose. The application is also responsible to avoid confusion from a delayed ICMP error message resulting from an earlier use of the same port(s).

Next: 4.1.3.4 UDP Checksums

Connected: An Internet Encyclopedia
4.1.3.3 ICMP Messages