Overview of Managing Network Services 350 The first step in planning your TCP/IP network is to take stock of what you have now. Find out what you have in place--how many segments or rings, how many hosts, what protocols, and what ca- pabilities of the routers or bridges used to connect the network together. You should also try to predict the amount of future growth to expect. Next, you need to consider what network capabilities are needed to support your business. For example, does your company need access to the Internet? Do you need support for protocols other than TCP/IP? Are there applications that use NetBIOS or host name resolution? Finally, if you are using Active Directory, you need to consider how your subnets will be used to divide your network into physical sites. Sites are defined as a collection of TCP/IP subnets that share a high bandwidth connection. They are created in the Sites and Services MMC. Active Directory will use sites in your network to control logon traffic, replication traffic, and access to network services such as Distributed File System (DFS) resources. . For more information, see Chapter 1.2, "Introduction to Active Directory." After you know what your network looks like and your business requirements, it's time to translate that information into an IP addressing scheme. IP Addressing After you know how many physical segments or rings, the maximum number of hosts per segment, and the location of default gateways, it's time to decide on an IP addressing scheme. To do that, you need to understand what is possible. In TCP/IP, each host is identified by a unique 32-bit IP address. When used with a subnet mask, each address is divided into a two-part address, consisting of a network ID and a host ID. The network ID identifies the particular subnet where the workstation or server can be found, just as the street name in your address identifies the particular street where