webpointmorpheus Network Info
Network Protocols

     Overview      Network Protocol Suites      NetBEUI      IPX/SPX
     TCP/IP      AppleTalk

©2005 - material compiled by Bob Carnaghi, www.webpointmorpheus.com

Overview     Top of Page

There is a distinction to be made between a protocol and a protocol suite which bear the same name. A protocol is a set of rules which are established for communication. A protocol suite is a collection of protocols that work together to gain a specified outcome. The intent of protocols in data communications (computers) is to standardize and define what elements in the protocol suite perform which actions, as well as when and where.

If you have a difficult time with the acronymn drenched terms used in this document, check out the Network Definitions Page.

Network Protocol Suites     Top of Page

Listed below are the major Protocol Suites. Click the link to proceed to the section for that particular protocol.

• NetBEUI - Microsoft protocol for small networks.
• IPX/SPX - a popular protocol suite (Novell Netware) that is proprietary, and recently incorporated support for TCP/IP.
• TCP/IP - The prolifically popular protocol suite, used on the Internet, as well as in many other configurations.
• AppleTalk - the network protocol suite used by Apple computers.

NetBEUI     Top of Page

NetBEUI is a simple, non-routable protocol that incorporates an early-computing network architecture designed by Microsoft. NetBEUI is still popular, mostly in systems which incorporate Windows 9x or NT. NetBEUI contains two main protocols: NetBIOS & NetBEUI, which work at the Session & Transport layers, respectively. NetBEUI can refer to either the NetBEUI protocol suite, or to the NetBEUI Transport layer protocol. The NetBEUI protocol bypasses the Network layer of the OSI. Communication is direct from the Transport layer to the Data Link layer.

NetBEUI uses WINS (Windows Internet Naming Service) to resolve NetBios names to IP addresses.

IPX/SPX Protocol Suite     Top of Page

The Netware protocol suite is an implementation of several protocols which serve functions corresponding to the seven layer OSI Model. Current versions (5.x) of Novell Netware have implemented TCP/IP, but previous versions (3.x & 4.x) used the proprietary IPX and SPX protocol was developed by Novell in the early 1980s and is based on the Xerox Network System. Netware is a Network Operating System (NOS) that allows file and printer sharing and mail functionality using a client-server architecture.

IPX is a connectionless Layer 3 (Network layer) protocol used to transfer datagrams between hosts and networks that is similar to IP (Internet Protocol) from the TCP/IP suite. SPX is the Transport Layer protocol that provides reliable transport for IPX datagrams, similar to TCP in the TCP/IP protocol suite.

NetWare operating systems prior to NetWare 4 relied on a database structure called the bindery. The NetWare bindery kept server-specific user and group information in a flat file which every network server maintained independent of the bindery on other servers, hence there was no relationship between objects. The bindery relied heavily on the Service Advertising Protocol to advertise its resources to clients. In Netware version 4, Novell introduced the NDS (Netware Directory Services). NDS allows network resources to be grouped together and organized in a hierarchical way. NDS uses the same concept as Microsoft's Active Directory.

Microsoft introduced NWLINK as a parallel implementation of IPX/SPX which allows Windows clients to communicate with Netware servers. Netware Loadable Modules (NLMs) are software modules that can be added to a Netware server installation to provide additional functionality. GroupWise is a groupware server and client that provides email and other services which are similar to MS Exchange Server and Outlook.

   IPX Addressing

IPX/SPX can run over Etnernet, Token Ring, FDDI and PPP WAN connections. IPX/SPX networks support a approximately 300 hosts per segment. A complete IPX network address is 80 bits, and is represented in a hexadecimal format. The network portion is 32 bits in length and is manually configured. The host portion is 48 bits long and is derived from the MAC address of the host's network interface.

Examples of full IPX internetwork addresses are:

	0CC001B8.0040.BF21.7C42
	0000ACCA.0070.8712.844B
	00000032.0050.E92A.C3A2

   Additional IPX/SPX Points

• This protocol suite is used exclusively by Novell NetWare.
• Works with the Network, Transport, Session, Presentation, and Application layers of the OSI.
• A Microsoft protocol - NWLink - is designed to interpret IPX/SPX packets.
• IPX works at the Network layer level of the OSI.
• SPX works at the Transport layer of the OSI.
• Microsoft networks can automatically detect the frame type of IPX/SPX protocol. Care must be taken when configuring nodes on a network that will use IPX/SPX that all nodes use the same frame type. If there is more than one frame type available on the network there can be a conflict that will result in network congestion.
• Connections between Servers and Clients are maintained by the Server Announcement Protocol (SAP).
• IPX/SPX does not scale well beyond a medium-size network.
• IPX running over Ethernet can use any one of four data structures defined by Ethernet 802.3, Ethernet II, or Ethernet SNAP.

TCP/IP     Top of Page

TCP/IP is the most prevalent protocol suite in use today. TCP/IP is the protocol suite that is used on the Internet - one cannot connect to the Internet without embracing TCP/IP. There is an entire page dedicated to in depth information about TCP/IP.

AppleTalk     Top of Page

Appletalk is based upon an obsolete protocol called LocalTalk. Like TCP/IP, AppleTalk is not just one protocol, but a suite of several protocols for different functions. AppleTalk was developed by Apple Computers to allow file & printer sharing and mail functionality between Macintosh computers. A Mac that shares resources is called a server, and the computer connecting to it a client. Network connectivity is inherent to every Macintosh computer and requires virtually no user interaction. Small Appletalk networks are easy to administer. AppleTalk is easily understood in correlation to the 7-layer OSI model.

At the Physical and Data Link layer several specifications are defined to allow AppleTalk to run over several network types with different media-access technologies. Uses Name Binding Protocol (NBP)

EtherTalk allows AppleTalk to run over Ethernet, TokenTalk allows AppleTalk to run over Token Ring, FDDITalk allows AppleTalk to run over FDDI, and LocalTalk is Apple's own media-access technology, and uses CSMA/CA as the access-method. LocalTalk uses UTP or STP cabling and has a maximum data transfer rate of 230 Kbps, you can still find this in today's networks, typically in very small environments for simple file and printer sharing.

At the Network layer, two main protocols are defined. DDP (Datagram Delivery Protocol) is a connectionless datagram protocol providing best-effort delivery. DDP is similar to IP in the TCP/IP suite. AARP (AppleTalk Address Resolution Protocol) Maps (Network) layer 3 addresses to (Data Link) layer 2 MAC addresses, which is similar to the function of the ARP protocol in TCP/IP.

An AppleTalk address is 24 bits in length. The address needs a network and a host portion, similar to TCP/IP. The first 16 bits are the network portion of the address. The next 8 bits are the node number on the network. Often there is an added socket number, for example 55.62.224 or 55.62/224. An AppleTalk socket is similar to the concept of ports in TCP/IP.