Networking Protocol Suites

By Stephen Bucaro

Network protocols define rules for handling data and communicating in a particular networking environment. Individual protocols operate at specific layers in the OSI reference model. A protocol suite is a group of protocols designed to work together. The three major protocol suites are NetBEUI, IPX/SPX and TCP/IP.

NetBEUI

IBM designed NetBIOS (Network Basic Input/Output System) for small workgroups that did not have a central server. NetBIOS establishes a communication session between computers. NetBEUI (NetBIOS Extended User Interface) is an enhancement of NetBIOS to provide the data transport services. NetBEUI was developed as part of IBM's LAN Manager network operating system.

Later, Microsoft used the NetBEUI protocol in Windows For Workgroups (Windows 3.11) to provide peer-to-peer networking ability. NetBEUI is used today to support networking on the Windows 9x and Windows NT operating systems. NetBEUI is a simple, fast protocol. It was not designed to communicate from one network to another, so it is not routable. It operates only at the transport and Network layers of the OSI model.

In a Microsoft Windows network operating system, you assign a NetBEUI name to each computer. This is the name you see in the Network Neighborhood directory listing. The name must adhere to the NetBEUI naming convention; it must be unique with a maximum of 15 characters with no spaces. The NetBEUI protocol addressing scheme assigns a one-character suffix to the computer's name to differentiate between the specific services or functions provided by the computer.

IPX/SPX

Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) is a protocol used by Novel's Netware product. IPX/SPX is based on the XNS/SPP (Xerox Network Systems/Sequenced Packet Protocol) designed by Xerox. IPX/SPX is composed of two main parts. One part is connectionless; the other part is connection based.

SPX is a connection oriented protocol. Connection-oriented protocols require a node to return an acknowledgement when a packet arrives and resending of the packet if an error occurs. This method provides reliability, but sending acknowledgements makes the transmission slower.

IPX is a connectionless protocol. Connectionless protocols don't require acknowledgements. When broadcasting a message to all nodes you usually do not want acknowledgements returned because this would increase the network traffic unnecessarily. Connectionless protocols operate faster.

IPX/SPX provides protocols for operating at the OSI network layer through to the application layer. At the network layer the IPX protocol handles the routing of data packets between networks. At the transport layer SPX handles the process of breaking data into smaller chunks on the sending end and reassembling them on the receiving end. Server Announcement Protocol (SAP) provides the session layer task of creating and maintaining connections. NetWare Core Protocol (NCP) handles the tasks of the presentation and application layers.

There are two types of addressing schemes. Physical addressing refers to the MAC address built into every NIC, this cannot be changed. Logical addressing refers to an address that is assigned or configured and can be changed. Of course in the end the logical address must be translated to the MAC address.

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