Connection Establishment Normal operation: Host 1 Host 2 •Host 1 sends CR containing a CR (seq = x) sequence number x •Host 2 replies ACK to host 1 announcing its initial sequence АСK (seq %3D y, ACК...

Subject: Networking

Question:
Explain the
timing diagrams
of two different connection establishment mechanisms of
TCP.

Note: Check the image and answer according to this.

Extracted text: Connection Establishment Normal operation: Host 1 Host 2 •Host 1 sends CR containing a CR (seq = x) sequence number x •Host 2 replies ACK to host 1 announcing its initial sequence АСK (seq %3D y, ACК %3 х) no. у •Host 1 acknowledges host 2's choice of initial sequence no. in DATA (seq = x, ACK = y) the first data TPDU that it sends (a) Connection Establishment Old CONNECTION REQUEST Host 1 Host 2 Old duplicate appearing out of nowhere: CR (seq = x) This TPDU arrives at host 2 without host 1's knowledge Host 2 reacts to this TPDU by ACK (seq = y, ACK = x) sending host 1 an ACK When host 1 rejects host 2's attempt to establish a connection, REJECT (ACK = y) host 2 realizes that it was tricked (b) by delayed duplicate Connection Establishment Duplicate CONNECTION REQUEST and duplicate ACK: Host 1 Host 2 CR (seq = x) Old duplicate •The worst case is when both a delayed CR and an ACK are floating around in the subnet ACK (seq = y, ACK = x) DATA (seq = x, ACK = z) Old duplicate REJECT (ACK = y) (c) Connection Release Two styles for terminating a connection 1. Asymmetric Release: When one party hangs up, the connection is broken. Telephone system 2. Symmetric Release: Treats connection as two separate unidirectional connections and requires each one to be released separately Connection Release Asymmetric Release:. It is abrupt and may result data Host 2 Host 1 CR loss АСK When the data is transferring DATA from host 1 to host 2, host 2 issues a DR DATA The result is that the DR No data are delivered after a disconnect request connection is released and data are lost