ICMP Time Exceeded
Encyclopedia
The Time Exceeded Message is an ICMP
message which is generated by a gateway to inform the source of a discarded datagram
due to the time to live
field reaching zero. A time exceeded message may also be sent by a host if it fails to reassemble a fragmented
datagram within its time limit.
Time exceeded messages are used by the traceroute
utility to identify gateways on the path between two hosts.
Type must be set to 11. The code, which specifies the reason for the time exceeded message, include the following:
The header and first 64 bits of the original payload are used by the source host to match the time exceeded message to the discarded datagram. For higher level protocols such as UDP
and TCP
the 64 bit payload will include the source and destination ports of the discarded packet.
Internet Control Message Protocol
The Internet Control Message Protocol is one of the core protocols of the Internet Protocol Suite. It is chiefly used by the operating systems of networked computers to send error messages indicating, for example, that a requested service is not available or that a host or router could not be...
message which is generated by a gateway to inform the source of a discarded datagram
Datagram
A datagram is a basic transfer unit associated with a packet-switched network in which the delivery, arrival time, and order are not guaranteed....
due to the time to live
Time to live
Time to live is a mechanism that limits the lifespan of data in a computer or network. TTL may be implemented as a counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded. In computer networking, TTL prevents a data...
field reaching zero. A time exceeded message may also be sent by a host if it fails to reassemble a fragmented
IP fragmentation
The Internet Protocol implements datagram fragmentation, so that packets may be formed that can pass through a link with a smaller maximum transmission unit than the original datagram size....
datagram within its time limit.
Time exceeded messages are used by the traceroute
Traceroute
traceroute is a computer network diagnostic tool for displaying the route and measuring transit delays of packets across an Internet Protocol network. Traceroute is available on most operating systems....
utility to identify gateways on the path between two hosts.
| 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type = 11 | Code | Header Checksum | |||||||||||||||||||||||||||||
| unused | |||||||||||||||||||||||||||||||
| IP Header + First 8 Bytes of Original Datagram's Data | |||||||||||||||||||||||||||||||
Type must be set to 11. The code, which specifies the reason for the time exceeded message, include the following:
| Code | Description |
|---|---|
| 0 | Time-to-live exceeded in transit. |
| 1 | Fragment reassembly time exceeded. |
The header and first 64 bits of the original payload are used by the source host to match the time exceeded message to the discarded datagram. For higher level protocols such as UDP
User Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...
and TCP
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
the 64 bit payload will include the source and destination ports of the discarded packet.