ICMP Timestamp
Encyclopedia
The Timestamp is an ICMP
message which is used for time synchronization. It consists of the originating timestamp
.
Message Format:
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 used for time synchronization. It consists of the originating timestamp
Timestamp
A timestamp is a sequence of characters, denoting the date or time at which a certain event occurred. A timestamp is the time at which an event is recorded by a computer, not the time of the event itself...
.
Message Format:
| 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 = 13 | Code = 0 | Header Checksum |
Identifier |
Sequence Number |
Originate Timestamp |
- Type must be set to 13.
- Code must be set to 0.
- The Identifier and Sequence Number can be used by the client to match the timestamp replyICMP Timestamp ReplyThe Timestamp Reply is an ICMP message which replies to a Timestamp message. It consists of the originating timestamp sent by the sender of the Timestamp as well as a receive timestamp and a transmit timestamp.Message Format:...
with the timestamp request. - The data transmitted (originate timestamp) in the timestamp is 32 bits in length and is the number of milliseconds since midnight UT.
- If the time is not available in milliseconds or cannot be provided with respect to midnight UT then any time can be inserted in a timestamp provided the high order bit of the timestamp is also set to indicate this non-standard value.