September 17, 1998

Definitions, Ethernet, TCP/IP, IP addressing...

Some Definitions:

LAN (Local Area Network): Popular technologies are:

WAN  (Wide Area Network): Usually leased telephone line
                                                Slower than LANs

MAN (Metropolitan Area Network):  Usually co-axial cable (similar to cable TV)

Host:  a computer on a network

Router: a host connected to two networks that can forward network messages from one network to another

User: a human that logs into a host

Networking Application:  Software that provides service over the network.  Networking applications generally interface with the Transport Layer.

Little-endian byte order:
      high-order ->     low-order
       A+1                  A           : Intel 486, DEC VAX

Big-endian byte order:
      high-order -> low-order
       A                  A+1          : IBM 370, Motorola 6800

Out-of-Band Data (or expediated data):

In order to communicate, host must speak the same protocol.
Each layer of the OSI Model has it's own protocol. If you change the protocol at one layer on a host, you must change it on all other hosts.

Let's look at some Physical and Data-Link Layer Protocols.

ETHERNET: Details of TCP/IP: IP Addresses Classes Special Addresses: