5.3 Networking
5.3.1 TCP/IP stack
The TCP/IP stack is shorter than the OSI one: TCP is a connection-oriented protocol; UDP (User Datagram Protocol) is a connectionless protocol.
5.3.2 IP datagram’s
The IP layer provides a connectionless and unreliable delivery system. It considers each datagram independently of the others. Any association between datagram must be supplied by the higher layers. The IP layer supplies a checksum that includes its own header. The header includes the source and destination addresses. The IP layer handles routing through an Internet. It is also responsible for breaking up large datagram into smaller ones for transmission and reassembling them at the other end.
5.3.3 UDP
UDP is also connectionless and unreliable. What it adds to IP is a checksum for the contents of the datagram and port numbers. These are used to give a client/server model - see later. …show more content…
It provides a virtual circuit that two processes can use to communicate.
5.3.5Internet addresses
In order to use a service, you must be able to find it. The Internet uses an address scheme for machines so that they can be located. The address is a 32 bit integer which gives the IP address. This encodes a network ID and more addressing. The network ID falls into various classes according to the size of the network address.
5.4 Network address
Class A uses 8 bits for the network address with 24 bits left over for other addressing. Class B uses 16 bit network addressing. Class C uses 24 bit network addressing and class D uses all 32.
5.4.1 Subnet address
Internally, the UNIX network is divided into sub networks. Building 11 is currently on one sub network and uses 10-bit addressing, allowing 1024 different hosts.
5.4.2 Host address
8 bits are finally used for host addresses within our subnet. This places a limit of 256 machines that can be on the