Windows Server 2003 Network Infrastructure

Windows Server 2003 Network Infrastructure

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Network Infrastructure is a set of hardware and software components used to interconnect computers and users. Infrastructure includes the transmission media, including telephone lines, cable television lines, and satellites and antennas, and also the routers, repeaters, and other devices that control transmission paths. In other words, you can say that Network infrastructure refers to physical and logical components that interconnect the hardware and software. The purpose of Network Infrastructure Plan is to establish the wide and local area network hardware, software, and maintenance. The primary goal of setting network infrastructure is as follows:

• Cost effective use of networks, equipment and software
• Productivity in sharing data
• Reliability of networks and equipments
• Training and support to users of technology

Physical infrastructure is the physical design of the network incorporated with cable, routers, switches, bridges, hubs, servers, and computers , which are associated with technologies, such as Ethernet, Public Switched Telephone Network (PSTN), and Asynchronous Transfer Mode (ATM). Logical infrastructure is the type of software that connects, manages, and secures hosts on a network. For example, network protocols, such as TCP/IP, and network services, such as Quality of Service (QoS) Packet Scheduler, are used for data communications. NIC uses a connector to connect to the physical medium. This protocol provides communications in a heterogeneous environment across interconnected networks of computers with various operating systems. It is a transport layer protocol that includes standards for communicating with computers.

In a TCP/IP network, each computer normally distinguishes itself by a specific IP address. TCP/IP uses IP addresses to locate and connect to host computers; but for users, it is easier to use names, instead of IP addresses, to locate or connect to sites. For example, users will be more comfortable in using the host name www.ucertify.com than using its IP address 66.111.64.227.

IP address is a four-byte number that uniquely identifies a computer on a TCP/IP network. It is made up of 32 bits of information. These bits are divided into four sections, each section containing one byte (8 bits). Each computer on the TCP/IP network must be assigned a unique IP address. People can refer to a computer by its name, instead of its network address. Windows network supports two name resolution methods, namely NetBIOS and DNS.

NetBIOS: NetBIOS provides two communication modes: session and datagram. Session mode lets two computers establish a connection, allows larger messages to be handled, and provides error detection and recovery. Datagram mode is connectionless. In this mode, each message is sent independently, so the messages must be smaller. In the datagram mode, the application is responsible for error detection and recovery. Datagram mode also supports the broadcast of a message to every computer on the LAN. NetBIOS provides services for the Name service for name registration and resolution, and for the Session service for connection-oriented communication. NetBIOS names are 16 bytes long, and there are very few restraints on the byte values that can be used. Non-alphanumeric characters can be used, but with some limitations and constraints.

Note: NetBIOS Extended User Interface (NetBEUI) is a small, fast protocol that was developed by IBM for workgroups and small LANs. It can be installed in the same way as other protocols. There are no configuration options for this protocol.

Windows Internet Name Service (WINS) is a name resolution service that registers and resolves NetBIOS names to IP addresses used on the network. WINS is a Microsoft standard and is used to centralize the process of registering and resolving NetBIOS names to IP addresses.


In Windows Server 2003, computers can be grouped into workgroups and domains. Computers working in Windows workgroup environment use the NetBIOS naming system to name computers and resolve the names. In a workgroup, every computer is the master of itself. In Windows NT/2000/2003, a domain is a set of network resources that are part of a network and share a common directory database. A domain is administered as a unit with common rules and procedures. Each domain has a unique name. Users just have to log on to a domain to access the network resources within it. Members of the same domain can utilize the resources of that domain. However, these resources can also be shared between domains.

Name resolution is handled in the network by NetBT broadcasts to the network segment. Common Internet File System (CIFS) is used to provide file sharing, security for network shares, network browsing, and printing within the workgroup.

Domain Name System



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A DNS name is a series of alphanumeric strings separated by decimal points, e.g., exams.microsoft.com. Here .com is the top-level domain and is registered in the root servers.

DNS server is a computer that runs the Domain Name System (DNS) service. It contains host name-to-IP address mappings, IP address-to-host name mappings, information about the domain tree structure, etc. A DNS server is also used to resolve DNS client queries.

An address can be configured manually, distributed automatically through the use of a DHCP server, or self-configured.

Dynamic Host Configuration Protocol (DHCP): DHCP is a service provided by DHCP servers. It dynamically assigns TCP/IP addresses to the clients on a network. It is a TCP/IP standard, which reduces the complexity and administrative overhead of managing a network. It prevents an administrator from manually configuring static IP addresses for individual resources. The default configuration for a computer running Windows Server 2003 is to automatically obtain an IP address from a DHCP server.

The DHCP service enables a computer to function as a DHCP server and configure DHCP-enabled client computers on a network. DHCP, which runs on a server, enables automatic and centralized management of IP addresses and other TCP/IP configuration settings for the network's client computers. A DHCP server must be authorized within Active Directory before it can lease IP addresses to DHCP clients.

Note: If the DHCP server is offline, a user cannot obtain necessary addresses from the server. Hence, without valid TCP/IP addresses from the DHCP server, the user will not be able to communicate with anyone on the network or access network resources.

DHCP scope in a DHCP server



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Automatic Private IP Addressing (APIPA) is a Windows 2000/2003 feature, which allows household users and small business users to create a functional single subnet TCP/IP network without manually configuring the TCP/IP protocol or setting up a DHCP server. Automatic Private IP Addressing (APIPA) has some limitations with the configuration of additional parameters such as a default gateway or DNS servers. You cannot configure a computer with a DNS server address, a default gateway address, or a WINS server address through APIPA.

APIPA: Automatic Private IP Addressing (APIPA) is an addressing feature that automatically assigns an Internet Protocol address to a computer on which it is installed. This occurs when the TCP/IP protocol is installed. When no DHCP server is available, the computer uses APIPA to assign an IP address to itself. If a DHCP server is available later, the computer changes its IP address to one obtained from the DHCP server. A computer can communicate with any other computers on the local network even if the computers are configured by APIPA or have static IP addresses manually set to the address range with a subnet mask of 255.255.0.0.

APIPA addresses are always in the range of 169.254.0.1 and 169.254.255.254 and use a subnet mask of 255.255.0.0. When a user configures a TCP/IP connection to obtain an IP address automatically, by default the computer tries to find a DHCP server for obtaining the address. The user obtains the address if the computer finds the DHCP server. If it does not find the DHCP server, the computer uses APIPA to configure a unique IP address for a computer in the network.

Note: Since APIPA does not offer a gateway address, it can never be used on the Internet, and the clients using APIPA cannot access resources outside the local subnet.

If you want to make it sure that Automatic private IP Addressing is currently enabled or active, type Ipconfig/all at the command prompt. It shows detailed information. If the resulting text reveals no address with or without an error message, you should check the network cable attachment and then run the Ipconfig/renew command to obtain a new IP address.

You can view the TCP/IP settings configured in the Internet Protocol (TCP/IP) Properties dialog box. In Windows Server 2003, you need not detect and configure local area network (LAN) connections. In the Network Connection menu, you can view the automatic connections along with manually configured connections and the New Connection Wizard. After setting up the connections, other network components such as network clients, services, and protocols are required to maintain connectivity in the network.

Network clients are types of software that configures local computers to connect to a network operating system. They enable users to use files and printers shared on other network computers, such as Novell NetWare, etc. Network services are software components that install services, such as file and printer sharing, on a computer so that other computers on the network can have access to the files and printers installed on that computer.

Protocols are considered as the building blocks of network communication. Computer protocols are used by communicating devices and software services to format data in a way that all participants understand. A group of protocols forms a protocol suite that is implemented in a similar network or used by a vendor for all its products, e.g., TCP/IP and AppleTalk. It provides a context to interpret communicated information.

AppleTalk: Windows 2000 versions support the AppleTalk protocol. This protocol suite comprises the following protocols:

• AppleShare: This is an Application layer protocol that supports file and print sharing.
• AppleTalk Filing Protocol (AFP): This protocol facilitates file sharing on a network. It operates at the Presentation and Application layers of the OSI Model.
• Printer Access Protocol (PAP): It provides printing services on the network. PAP operates at the Session layer of the OSI Model.
• AppleTalk Data Stream Protocol (ADSP): It is a connection-oriented protocol that helps establish a connection between the network devices. This protocol works at the Session and Transport layers of the OSI Model.
• AppleTalk Session Protocol (ASP): This protocol is used to establish a connection and release it when the message is sent between various devices on the network. It operates at the Session layer of the OSI Model.
• Routing Table Maintenance Protocol (RTMP): It maintains routing tables on a network. It operates at the Transport layer of the OSI Model.
• AppleTalk Address Resolution Protocol (AARP): This protocol maps the Apple Talk addresses to the physical Token Ring and Ethernet addresses. It operates at the Network layer of the OSI Model.
• Zone Information Protocol (ZIP): In a Macintosh network, the network devices are divided into logical groups known as Zones. This protocol is used to divide the network devices into logical zones. It operates at the Session layer of the OSI Model.

TCP/IP:

You can view the advanced connection settings from the Advanced Settings dialog box. The Provider Order tab of the Advanced Settings dialog box displays the order in which various network providers, such as a NetWare, Microsoft Windows Network, or Microsoft Terminal Services, will be attempted. By default, Microsoft Terminal Services is given priority over other network connections.

The Management and Monitoring Tools component allows you to manage and monitor devices on TCP/IP networks. You can capture and analyze packets over a network.

The optional services can be added to existing Windows Server 2003 computers by using Add/Remove Programs or the Windows Server 2003 Configure Your Server Wizard, or by creating a customized automated installation of Windows Server 2003.

Extending a Windows Server 2003 Network Infrastructure

You can extend Windows Server 2003 default network infrastructure by installing additional network components. But excessive services and components can reduce the network performance. In Control Panel, from the Add/Remove Programs tool you can perform additional network function of Windows Server 2003. When you install client services for Netware, the NWLink (IPX) protocol gets installed automatically.

NWLink: Windows clients running NWLink and either the Client Service or the Gateway Service for NetWare, can connect to NetWare servers and utilize their file and print services.

Note: NWLink supports Winsock and NetBIOS over IPX networking application programming interfaces (APIs), which provide interprocess communication (IPC) services.

IPX: The IPX frame type describes the method of encapsulating data in an IPX packet. IPX is the network-layer routing protocol used in the Novell NetWare environment. The primary tasks of IPX are addressing, routing, and switching information packets from one location to another on a network. In a LAN-based client, the network interface card (NIC) provides network node addressing, and in a tunneled environment, it is the gateway that provides the network node addressing. It is supported by Microsoft operating systems. IPX can be used for both large and small networks.

Note: The private LAN can carry IP and IPX traffic simultaneously.

The Windows Component provides services for issuing certificates. A certificate is a digital representation of information that identifies authorized users on the Internet and intranets. It can be issued to perform a number of functions such as Web server authentication, secure e-mail, etc. A certificate is valid only for the period of time specified within it. Moreover, a user can set the duration for a certificate's validity. Certificates are issued by certification authorities (CAs).

In Windows Server 2003 networks, a domain is created and supported by Microsoft Active Directory directory service. In Windows NT/2000/2003, a domain is a set of network resources that are part of a network and share a common directory database. A domain is administered as a unit with common rules and procedures. When you install Active Directory on your network, it promotes a computer to the status of a domain controller.

Domain controller (DC) is one of the greatest features for maintaining user database of Windows Server 2003. It is responsible for maintaining the Active Directory data store, its all objects, and security of all the devices on a network. Data can be modified at any domain controller within the domain because Active Directory synchronizes the information between domain controllers. The purpose of Active Directory replication is to ensure that the information stored on the domain controllers remains synchronized. One of the main features associated with Active Directory is the global catalog. The global catalog enables network logon by providing group membership information to the domain controller, and enables the finding of objects and directory information even in a large multi domain environment.

Summary

• Physical infrastructure is the physical design of a network. A network's logical infrastructure is made up of many software elements that connect, manage, and secure the hosts on the network.
• Computer protocols are used by communicating devices and software services to format data to facilitate communication between the computers in a network having different types of hardware and software.
• Computers working in Windows workgroup environment use the NetBIOS naming system to name the computers and resolve the names.
• DNS server is a computer that runs the Domain Name System (DNS) service. It contains host name-to-IP address mappings, IP address-to-host name mappings, information about the domain tree structure, etc. A DNS server is also used to resolve DNS client queries.

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