TCP Connection Tear-Down
Need to tear down both directions of the TCP connection. Uses modified 3-way handshake:
- A ---- Seq k, ACK j+1, FIN+ACK ------> B
- A <--- Seq j, ACK k+1, ACK <-- B
- ... sometime later ...
- A <--- Seq j, ACK k+1, FIN+ACK <-- B
- A ----> Seq k, ACK j+1, ACK ----> B