Overview of Transport Protocols

How DHCP works
When you start TCP/IP operations you are actually broadcasting a request for address information.
The DHCP server receives the request assigns a new address for a specific time period (called a lease period) and sends it to you together with the other required configuration information
This information is acknowledged by you and used to set up its configuration.
During the lease period the DHCP server will not reallocate the address and attempts to return the same address every time you request an address.
You extend the lease by giving subsequent requests and may send a message to the server before the lease expires telling it that it no longer needs the address so it can be released and assigned to another client on the network.
Other settings such as default gateway DNS (Domain Name System) and WINS (Windows Internet Naming Service) servers may be passed to the workstation at the same time.
IPX/SPX (NWLink)
The creators of NetWare network operating system i.e. Novell developed this Protocol.
This protocol has been derived from the Xerox Network System (XNS) which was developed by Xerox in the late 1970's.
Microsoft also has a version of this protocol called NWLink.
The Microsoft version of this protocol is fully compatible with Novel IPX/SPX.
The NetWare Protocol Suite takes its name from the two main protocols at the Network and Transport layers of the OSI model:
IPX (Internetworking Packet eXchange)
SPX (Sequential Packet eXchange)
The NetWare Protocol suite provides file print message and application services.
This architecture is server-centric because workstations make requests for file services or other services from the server.
To the user at a workstation all resources appear to be local to that workstation.
For example saving a file to a file server on the network is simply a matter of saving it to a drive F (or another mapped drive).
IPX deals with addressing route selection and an end-to-end connectivity of computers.
IPX is not suitable for certain types of network communication (where reliability of data reaching the remote machine is important) because it does not maintain a connection state (i.e. it is connectionless).
In a connectionless packet delivery system packets are simply sent to the destination and there is no confirmation of the packet reaching the destination.
In a connection oriented packet delivery system the status of the packet is known and the packet delivery is confirmed.
Most of the communication on a network including workstation connections and printing use SPX.
SPX is a transport layer protocol which provides connection-oriented packet delivery and is used when IPX datagram packet delivery is not reliable enough such as for a print server.
This protocol is concerned with addressing of machines segment development (including division and combination) and connection services (packet sequencing error control and end-to-end flow control).
NetBEUI
Pronounced net-booey NetBEUI is short for NetBIOS Enhanced User Interface.
It is an enhanced version of the NetBIOS protocol used by network operating systems such as LAN Manager LAN Server Windows for Workgroups Windows 95 and Windows NT.
NetBEUI was originally designed by IBM for their LAN Manager server and later extended by Microsoft and Novell.
NetBEUI Developed in the year 1985 by IBM for its PC networks.
NetBEUI for many years was Microsoft's preferred protocol.
It used this protocol for its LAN Manager and its early NT products.
However later versions of NT Microsoft switched to its own implementations of TCP/IP.
At first NetBIOS and NetBEUI were considered to be one.
Later however NetBIOS was separated for use with other protocols e.g. TCP/IP and IPX/SPX.
NetBIOS API however became popular later on.
This was because of its ability to provide software programmers with an easy means of accessing and utilizing network resources.