TCP/IP is an industry-standard suite of protocols designed for WANs. Adding TCP/IP to a Windows 2000
configuration offers several advantages, including high interoperability, reliability, scalability,
and security. Windows 2000 supplies a number of utilities that can help you connect to other
TCP/IP-based hosts or help you troubleshoot TCP/IP connection problems.
TCP/IP protocols use a four-layer conceptual model: Application, Transport, Internet, and Network
Interface. IP works at the Internet level and supports virtually all LAN and WAN interface
technologies, such as Ethernet, Token Ring, Frame Relay, and ATM. IP is a connectionless protocol that
addresses and routes packets between hosts. IP is unreliable because delivery is not guaranteed.
At the Transport Layer, TCP provides IP with reliable, connection-oriented delivery. Once a session is
established, TCP delivers data through unique port numbers to applications. UDP, an alternative
transport protocol to TCP, is a connectionless datagram service that does not guarantee delivery of
packets. It is used by applications that do not require an acknowledgment of data receipt.
Each TCP/IP host is identified by a logical IP address, and a unique IP address is required for each host
and network component that communicates using TCP/IP. Each IP address defines the network ID and
host ID. An IP address is 32 bits long and is composed of four 8-bit fields, called octets. There are
five address classes. Microsoft supports Class A, B, and C addresses assigned to hosts. Each address
class can accommodate networks of different sizes.
There are several guidelines you should follow to make sure you assign valid IP addresses. All hosts on a
given network must have the same network ID to communicate with each other. All TCP/IP hosts,
including interfaces to routers, require unique host IDs.
By default, Windows 2000 installs the TCP/IP protocol if Setup detects a network adapter. You can also
manually install TCP/IP. After you install TCP/IP on a computer, you can either configure it to obtain
an IP address automatically, or set configuration properties manually. You can also implement
packet filters to limit the type of access allowed to and from the network to restrict traffic to
Routers forward packets from one physical network to another. The IP layer consults a routing table that
is stored in memory. A routing table contains entries with the IP addresses of router interfaces to
other networks. Static routers require that routing tables are built and updated manually. With
dynamic routing, if a route changes, other routers are automatically informed of the change.