Internetworking through TCP/IP
"The goal of internetworking is universal service across heterogeneous networks."
Importance of Routers
Internetworks are formed by connecting networks with routers.
Routers are defined as devices that operate from the network level on down.
Routers can be used to join networks of differing technologies, such as a LAN to a WAN.
Routers have a split personality, one part for each network technology, along with the logic to transform data between their protocols.
Router provides smooth and transparent connection between two dissimilar networks.
The dominant protocol of internetworking is TCP/IP.
Transmission Control Protocol / Internet Protocol
The TCP/IP structure is 5 layer reference model:
- Physical
corresponds to OSI physical (hardware).
- Network interface
corresponds to OSI datalink (building and transmitting frames).
- Internet
corresponds roughly to OSI network, handles internet packet formats and packet forwarding.
- Transport
corresponds to OSI transport.
- Application
corresponds to OSI presentation plus application. Router doesn't have this.
Conceptually, internet consists of hosts and routers.
Hosts are communication endpoints and run the entire TCP/IP protocol stack.
Routers do not have the TCP/IP application layer.
Brief history of TCP/IP
Origin: Dept. of Defense, Advanced Research Projects Agency (ARPA), late 1960’s. A military and research network.
Originally called ARPANET, but because its goal was internetworking, it became known later as the ARPA Internet, then the Internet, and now (it seems), just the Net.
TCP/IP internet protocol suite was developed as part of ARPANET project.
Unique at the time because its specifications were made public (an open system).
TCP/IP spread from the military into academia through an agreement with UC-Berkeley.
- Berkeley agreed to include TCP/IP networking software with the BSD Unix operating system
whose source code it distributed freely to universities. Bill Joy, who later co-founded Sun Microsystems, was the principle designer of BSD Unix.
IP fits into the OSI network layer
IP topics
TCP fits into the OSI transport layer
Transport layer overview
TCP topics
Related Home Pages:
notes | CSC 465 | Peter Sanderson | Computer Science | SMSU
Last reviewed: 14 July 1999
Peter Sanderson ( pete@csc.smsu.edu )