Network Protocols

Not so long ago the second-most important choice you had to make when you created a network was which network protocol to use because the network protocol affects which types of computers your network can connect. Today, the choice has largely been made for you.

The three major network protocols are TCP/IP, IPX/SPX, and NetBEUI. Unlike data-link protocols, though, network protocols are not tied to particular hardware (NIC or cable) choices. Network protocols are software and can be installed to or removed from any computer on the network at any time as necessary. Today, TCP/IP has evolved to become the dominant protocol for large and small networks alike. Table 18.9 summarizes the differences between these protocols.

Table 18.9. Overview of Network Protocols and Suites

Protocol	Best Used for	Notes
TCP/IP	Most Windows-based networks	Native protocol suite for Windows 2000/XP and Novell NetWare 5.x/6.x; also used for dial-up Internet access
IPX/SPX	Novell 4.x and earlier networks	Used by NetWare 5.x for certain special features only
NetBIOS	Older Windows for Workgroups or DOS-based peer networks	Simplest protocol; can't be routed between networks; also used with Direct Cable Connection "networking"

All the computers on any given network must use the same network protocol or protocol suite to communicate with each other.

IP and TCP/IP

IP stands for Internet Protocol; it is the network layer of the collection of protocols (or protocol suite) developed for use on the Internet and commonly known as TCP/IP (Transmission Control Protocol/Internet Protocol).

Later, the TCP/IP protocols were adopted by the Unix operating systems, and they have now become the most commonly used protocol suite on PC LANs. Virtually every operating system with networking capabilities supports TCP/IP, and it is well on its way to displacing all the other competing protocols. Novell NetWare 6 and Windows XP both use TCP/IP as their native protocol for most services.

TCP/IPLAN and Dialup Networks

TCP/IP, unlike the other network protocols listed in the previous section, is also a protocol used by people who have never seen a NIC. People who access the Internet via modems (with what Windows 9x calls Dial-Up Networking) use TCP/IP just as those whose web access is done with their existing LANs. Although the same protocol is used in both cases, the settings vary a great deal.

Table 18.10 summarizes the differences you're likely to encounter. If you access the Internet with both modems and a LAN, you must ensure that the TCP/IP properties for modems and LANs are set correctly. You also might need to adjust your browser settings to indicate which connection type you are using. Table 18.10 provides general guidelines; your ISP or network administrator can give you the specific details.

Table 18.10. TCP/IP Properties by Connection TypeOverview

TCP/IP Property Tab	Setting	Modem Access (Dialup Adapter)	LAN Access (Network Card)
IP Address	IP Address	Automatically assigned by ISP	Specified (get value from network administrator) or automatically assigned by a DHCP server on the network (DHCP servers are often built in to gateways and routers)
WINS Configuration	Enable/Disable WINS Resolution	Disabled	Indicate server or enable DHCP to allow NetBIOS over TCP/IP
Gateway	Add Gateway/List of Gateways	Automatically assigned by ISP	IP address of gateway used to connect LAN to Internet
DNS Configuration	Enable/Disable Host Domain	Automatically assigned by ISP	Enabled, with host and domain specified (get value from network administrator)

As you can see from Table 18.10, correct settings for LAN access to the Internet and dialup networking (modem) settings are almost always completely different. In general, the best way to get your dialup networking connection working correctly is to use your ISP's automatic setup software. This is usually supplied as part of your ISP's signup software kit. After the setup is working, view the properties and record them for future troubleshooting use.

Note

In Windows 98 and Me, Microsoft recommends that TCP/IP properties be viewed through the Dial-Up Networking icon for the connection, rather than through the Network icon in the Control Panel. This is because different dialup connections could use different TCP/IP properties, which would override the default properties for the Dial-Up Adapter listing in the Network properties.

In Windows 2000 and XP, all types of networking are viewed and configured through a single interface.

IPX

The IPX protocol suite (often referred to as IPX/SPX) is the collective term for the proprietary protocols Novell created for its NetWare operating system. Although based loosely on some of the TCP/IP protocols, Novell privately holds the IPX protocol standards. However, this has not prevented Microsoft from creating its own IPX-compatible protocol for the Windows operating systems.

IPX (Internetwork Packet Exchange) itself is a network layer protocol that is equivalent in function to IP. The suite's equivalent to TCP is the Sequenced Packet Exchange (SPX) protocol, which provides connection-oriented, reliable service at the transport layer.

The IPX protocols typically are used today only on networks with NetWare servers running older versions of NetWare and often are installed along with another protocol suite, such as TCP/IP. Novell has phased out its use of IPX for NetWare support and switched to TCP/IPalong with the rest of the networking industrystarting with NetWare 5. NetWare 5 uses IPX/SPX only for specialized operations. Most of the product uses TCP/IP. NetWare version 6 and above use TCP/IP exclusively.

NetBEUI

NetBIOS Extended User Interface (NetBEUI) is a protocol that was used primarily on small Windows NT networks, as well as on peer networks based on Windows for Workgroups and Windows 9x. It was the default protocol in Windows NT 3.1, the first version of that operating system. Later versions, however, use the TCP/IP protocols as their default.

NetBEUI is a simple protocol that lacks many of the features that enable protocol suites such as TCP/IP to support networks of almost any size. NetBEUI is not routable, so it can't be used on large internetworks. It is suitable for small peer-to-peer networks, but any serious Windows NT/2000/XP network installation should use TCP/IP.

NetBEUI is still useful for creating "instant networks" with the Direct Cable Connection (see the following), and it is the minimum protocol required for use in a Windows 9x peer-to-peer network.