Panasonic UF-E1 Service Manual page 171

6.5.4. Transport Layer
6.5.4.1. TCP (Transmission Control Protocol)
The TCP (Transmission Control Protocol) is an internetwork connection-oriented protocol that corresponds
to the OSI Transport layer. TCP provides full-duplex, end-to-end connections. When the end-to-end com-
munication acknowledgement is not required, the UDP (User Datagram Protocol) can be substituted for the
TCP at the Transport (host-to-host) level. TCP and UDP operate at the same layer.
The UDP is a connectionless oriented protocol.
Header Length
(4 bit)
UF-E1
The client (UF-E1) generates random sequential numbers initially and sends them to the server. The initial
sequetial numbers are synchronized with the clock and increments the counterevery 4 msec.
The Server responds with an acknowledgement that increments the initial sequential number by one. The
ACK bit number is also changed to a "1" value. The "SYN" can have and identical "ACK" response for each
packet, thus, the server and the client can establish a connection.
IP Datagram
IP Header TCP Header
(20 byte) (20 byte)
TCP Segment in IP Datagram
Source Port (2 byte)
Sequence Number (4 byte)
Acknowledgment Number (4 byte)
Reserved Control Flag
(6 bit) (6 bit)
Checksum (2 byte)
Option
Data (Segment)
TCP Segment Outline
TCP 3 Handshake General Flowchart
TCP segment
Application D ata
(vary)
Destination Port (2 byte)
Window (6 byte)
Urgent Pointer (2 byte)
Increments No. sequentially
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UF-E1
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