In this section, we cover ways to plan and modify a network topology. Why is this important? If you need to add on to or alter your network topology, you need to focus on the following areas before you do:
Planning Physical Placement of Network Resources
Now that you are familiar with how to plan a TCP/IP network, let's look at where you may want to place devices on a network. Before we get into the exact details you need to know, let's talk about why planning the placement is so important in the first place. First, you should know how a network is laid out before you deploy it. You should know what you want a network to look like before you even contemplate ordering gear to populate it. This step is important because you must consider many factors before implementation. These factors include the following:
Looking at these questions before you plan anything is critical because you may change your mind during the implementation. It is possible that before you are even done rolling it out you will find something you would have done differently or better. Long story short, you need to plan physical placement of resources before you deploy them, and the best way to do this is to use a topology map. Now you can answer the questions that you posed to yourself. Let's look at each in detail:
Selecting Network Protocols
Now that you know how to place devices on your network, let's look at what protocols to use. Besides TCP/IP, we also mentioned other protocols earlier in this chapter. Here, we discuss routing and routed protocols and when or why to choose them. We also describe how to manage the protocols you are using, as well as why you may or may not want to use them. When you want to plan for protocols besides TCP/IP (which we have covered throughout this chapter), you may need to consider the following protocols in your network infrastructure:
We cover only these three because the point behind the whole objective is not to be an expert in any other protocol but TCP/IP, but to be able to recognize a need for other protocols in your network infrastructure, how to identify them, and how to plan for them. IPX/SPXIPX/SPX, which stands for Internetwork Packet Exchange/Sequence Packet Exchange , is similar to TCP/IP. You can think of IP mapping to IPX and TCP mapping to SPX. These protocols perform similar operations. IPX/SPX was originally created and used extensively by Novell with its NetWare platform of network operating systems. Although IPX/SPX was a great protocol, TCP/IP became the protocol of the Internet. To avoid missing out on the Internet revolution, all NOS vendors chose to develop TCP/IP into all their solutions moving forward, leaving in other protocols such as IPX/SPX only for backward compatibility. Novell NetWare version 5.0 was the first version to be shipped with a real version of TCP/IP, whereas the older versions of NetWare (versions 4.x and earlier) used add-on packs and NetWare IP (NWIP). Because IPX/SPX was more readily adopted into the earlier network system platforms, Novell NetWare versions 4.x and earlier and some Novell Directory Services (NDS) functions did not work without IPX/SPX installed. Wherever you work in the field, you may run into older systems on a network running NetWare 4.x and earlier; therefore, IPX/SPX will be running as well. Consequently, you, the Microsoft Certified Professional, need to know how and when to deploy IPX/SPX into or out of your network if necessary. SNASystems Network Architecture (SNA) is an old but still widely used protocol. Developed by IBM, SNA is a protocol suite that runs on most mainframes used today. Microsoft professionals who know only Microsoft may be shocked to learn that in today's networks they most likely will be confronted with some form of mainframe and may also be responsible for network connectivity to it. SNA Server was an older Microsoft Backoffice product that helped Windows users connect to and print on an IBM mainframe via the SNA protocol. This solution has since been renamed Host Integration Server (HIS) 2000. Again, it is important that you understand that SNA may exist in your network and that you need to know how to work with it. NetBIOSAnother old protocol, the Network Basic Input/Output System (NetBIOS) is a session layer communications service used by client and server applications in IBM-based token-ring and PC LAN Ethernet-based networks. NetBIOS is really just a way for application programming interface “based communications to take place. This means that higher-level services can run over lower-level protocols such as IP. This process is known as NetBIOS over TCP / IP (NBT) . The NetBIOS service contains three main sections: the name , session, and datagram services. Why do you need to know about such a protocol? You will be using NetBIOS names if you have older systems running WINS because they are not on DNS, which would require a Windows 2000 (or newer ) network. Older systems rely on NetBIOS, so until you can upgrade all your systems, you will have to use it. |