TCP MSL && TTL

TCP MSL && TTL

MSL is maximum Segment lifetime English abbreviation, Chinese can be translated as "maximum message survival time", he is any message on the network for the longest time, more than this time the message will be discarded. Because the TCP message (segment) is the data part of the IP datagram (datagram).

There is a TTL field in the IP header, the TTL is the abbreviation of time to live, the Chinese can be translated as "lifetime", the time to live is the initial value set by the source host but not the specific time, but instead of storing an IP datagram can pass the maximum number of routes, each through a processing his router this value minus 1, When this value is 0, the datagram is discarded and an ICMP message is sent to the source host. The MSL is specified in RFC 793 for 2 minutes, and the actual application is 30 seconds, 1 minutes and 2 minutes.

The TTL is related to the MSL but is not a simple equal relationship, and the MSL is greater than or equal to the TTL.

TCP MSL && TTL