TCP/IP | Tech Info | Network Information | TCP protocol | Addressing | Well Known Ports |

Transmission Control Protocol/Internet Protocol (TCP/IP) -

A collection of protocols, including the TCP, IP, e-mail, file transfers and others which makes possible the communication between differently configured computers and operating systems.

For an explanation of TCP Addressing see the TCP/IP mask addressing page.

For the TCP/IP "Well Known Ports" see the "TCP/IP Well Known Ports" page.

TCP/IP offers:

• Flow control using sliding windows
• Is acknowledged, full-duplex, connection-oriented
• IP uses Time-to-Live to limit the length of a datagram's life
• Both the network and node addresses are included in the IP address
• TCP/IP functions at the layers above the Physical and Data-Link Layers of the OSI model.

The TCP packet Breakdown

Byte Location	Item
0-31	Source Port
32-63	Destination Port
64 - 95	Sequence #
96 - 127	Acknowledgement #
128 - 131	Data Offset
132 - 137	Reserved
138	URG
139	ACK
140	PSH
141	RST
142	SYN
143	FIN
144 - 159	Windows
160-175	Checksum
176 - 191	Urgent Pointer
192 - 223	Options/Padding
224 -	Data ---

IP offers:
- Functions at the Network Layer of the OSI model
- Offer Datagram services
- Uses RIP
- Is a connectionless protocol
- Limits how long a packet can exist on the network

Included in TCP/IP are also the following protocols:

• Remote Terminal Emulation -
• File Transport Protocol (FTP)
• Trivial File Transfer Protocol (TFTP).
• Simple Mail Transfer Protocol (SMTP).
• Remote Procedure Calls (RPCs).
• Routing Information Protocol (RIP).
• eXternal Data Representation (XDR).
• Network File System (NFS).
• Internet Control Message Protocol (ICMP).
  • Echo Request/Reply - The PING utility uses ICMP to determine whether an IP address is reacheable and if the node is responding.
  • Destination Unreachable - ICMP reports when the destination was not reached
  • Time Exceeded - Reports to the sender when a packet's Time-to-Live has expired.
  • Redirect - If a better route is found for the packet ICMP reports it back to the router.
  • Source Quench - ICMP requests the sender to decrease the sending rate if data cannot be received fast enough.

 

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