The TIME_WAIT (2MSL) State

• When a TCP connection is terminated, both hosts put the socket into the TIME_WAIT state

• • Socket = {srcIP, dstIP, IPproto, srcPort, dstPort}

• Each TCP implementation chooses a maximum segment lifetime (MSL) value

• • Typical values: 30 seconds, 1 minute, 2 minutes

• A socket in TIME_WAIT must not be used again for twice the MSL time

• • Reduce the chances of a delayed packet from a previous connection being used in a new connection
  • This is one reason why ephemeral port numbers are typically chosen in a round-robin fashion