TTL (Time To Live)

A field in the Internet Protocol version 4 (IPv4) header that specifies the length

of time in seconds that the datagram can live in the Internet system.The maximum length of time is 255

seconds (28-1, with 0 not considered, as it is the official time of death), or 4.25 minutes. From the instant the IP datagram enters the Internet, each gateway and host that acts on the datagram decrements the TTL

by at least one second, although the time it has possession of the datagram generally is much less. When the TTL reaches 0, the datagram is declared dead and is discarded. The TTL mechanism prevents packets from wandering the Internet for eternity, at which point they would have no value, and would only

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• segmentation
• segmentation and reassembly (SAR)
• seizure
• selective call acceptance
• selective call block
• selective call forwarding
• selective call rejection
• selective ringing
• selector
• selenium
• self-healing
• self-learning bridge
• semiconductor
• send and pray
• sender
• Sequenced Packet Exchange (SPX)
• serial communications
• serial communications
• serial-in, parallel-out (SIPO)
• Serial Line Internet Protocol (SLIP)
• serial line protocol
• Serial Storage Architecture (SSA)
• server
• service
• service access point identifier (SAPI)