Chapter 3: Planning Network Protocols and Compatibility

Protocol A protocol consists of guidelines for: How data is formatted into discrete units called packets and frames How packets and frames are transmitted across one or more networks How packets and frames are interpreted at the receiving end

Packets and Frames Packets and frames are units of data transmitted from one networked computer or device to another. Although packets and frames are often used to have the same meaning, there is a difference. Packets operate at a higher communication layer and contain routing information.

General Sections in Packets and Frames Header Data Trailer or footer

Packet and Frame Format Figure 3-1 Basic packet and frame format

Network Design The basic design of a network is its topology Topology: The physical layout of the cable and the logical path followed by network packets and frames sent on the cable

Local Area Network Local area network (LAN): Joins computers, printers, and other computer equipment within a limited service area and generally employs only one topology

Example of a LAN Figure 3-2 A LAN in a building

Metropolitan Area Network Metropolitan area network (MAN): A network that links multiple LANs within a large city or metropolitan area

Example of a MAN Research hospital University chemistry building Pharmaceutical company MAN connecting buildings in a city

Enterprise Network Enterprise Network: A network that often reaches throughout a large area, such as a college campus, a city, or across several states. A distinguishing factor of an enterprise network is that it brings together an array of network resources such as many kinds of servers, mainframes, printers, network devices, intranets, and the Internet

Typical Resources in an Enterprise Network Figure 3-3 Resources in an enterprise network

Wide Area Network Wide Area Network (WAN): A far- reaching system of networks that can extend across state lines and across continents

Example of a WAN WAN across a continent

Network Interface Card Communication Medium Options Coaxial cable (thick and thinnet) Twisted-pair (shielded and unshielded) Fiber-optic Wireless (infrared, radio wave, microwave, satellite)

Connecting a Medium to a NIC Figure 3-4 Connecting cable to a NIC

Device Address Each NIC has a physical or device address that is burned into a PROM on the card Media access control (MAC) address is another way of describing the device address

Ethernet and Token Ring Ethernet: A network transport system that uses a carrier sensing and collision detection method to regulate data transmissions Token ring: A network transport method that uses a token, which is passed from node to node, to coordinate data transmissions

NDIS Network Driver Interface Specification (NDIS): developed by Microsoft and 3COM enables communication between a NIC and a protocol enables the use of multiple protocols on the same network

NDIS Architecture Figure 3-5 Binding a protocol to a NIC

ODI Open Datalink Interface (ODI) driver: Novell NetWare transport multiple protocols on the same network

Microsoft-Supported Communication Protocols

Microsoft-Supported Protocols

TCP/IP Transmission Control Protocol (TCP) portion performs extensive error checking to ensure that data is delivered successfully Internet Protocol (IP) portion consists of rules for packaging data and ensuring that it reaches the correct destination address

Dotted Decimal Notation Dotted Decimal Notation: four octets converted to decimal (e.g., )

Unicasting and Multicasting Unicast sent to each client e.g. a multimedia presentation Multicast sent to all requesting clients as a group (reducing the total network traffic)

Unicasting and Multicasting Compared Figure 3-6 Unicasting compared to multicasting

Subnet Mask Subnet mask: used to indicate the class of addressing on a network divides a network into subnetworks controls traffic and enforce security

Configuring the IP Address and Subnet Mask Figure 3-7 IP address and subnet mask setup

Static and Dynamic Addressing Dynamic addressing: automatically assigning an IP address to a network host Static addressing: manually assigning an IP address to a network host

TCP/IP Advantages Well-suited for medium and large networks Designed for routing high degree of reliability Used worldwide for directly connecting to the Internet and by Web servers Enables lower TCO on Microsoft networks

TCP/IP Advantages Compatible with standard tools for analyzing network performance Parallel ability to use DHCP and WINS through a Windows 2000 server Ability for diverse networks and operating systems to communicate Compatible with Microsoft Windows Sockets

TCP/IP Disadvantages More difficult to set up and maintain than other protocols Somewhat slower than IPX/SPX and NetBEUI on networks with light to medium traffic

Routing via TCP/IP Figure 3-8 Router forwarding packets to a designated network

Planning Tip For medium and large sized networks, plan to use TCP/IP because it enables you to manage and secure network traffic through creating subnets

Protocols and Applications in the TCP/IP Suite

IPX/SPX IPX: developed by Novell particularly for NetWare versions before version 5 SPX: connection-oriented protocol used for network transport when there is a particular need for data reliability

NWLink A network protocol that simulates the IPX/SPX protocol for Microsoft Windows 95, 98, NT, and 2000 communications with Novell NetWare file servers and compatible devices

Client Service for NetWare (CSNW) Components Client Service for NetWare NWLink IPX/SPX NWLink NetBIOS

CSNW Installed in Windows 2000 Figure 3-9 Windows 2000 with CSNW components installed

Configuring NWLink Configure three elements: Frame type Network number Internal network number

When to Configure the Internal Network Number When the NetWare server that is accessed uses two or more frame types When the Windows 2000 host has two or more NICs and NWLink is bound to more than one of the NICs When an application uses NetWare’s Service Advertising Protocol (SAP)

When to Use NWLink To access a NetWare server pre-version 5 To set up Windows 2000 as a gateway to a NetWare server To enable NetWare clients to access a Windows 2000 server

Planning Tip If you upgrade NetWare servers to version 5.x or higher, convert from IPX/SPX to TCP/IP for better network communication options and better compatibility with Windows 2000 servers

NetBIOS A combination software interface and network naming convention Available in Windows 2000 through the files Netbt.sys, NetBIOS.sys, and NetBIOS.dll

NetBEUI NetBIOS Extended User Interface (NetBEUI): A non-routable communications protocol native to early Microsoft network communications

NetBEUI and NetBIOS Communication Figure 3-10 NetBIOS/NetBEUIcommunication

Planning Tip When you upgrade from Windows NT Server to Windows 2000 Server, plan to retire NetBEUI implementations (if possible) and convert upgraded servers and clients to TCP/IP for more functionality

When to Use NetBEUI For temporary backward compatibility when converting from Windows NT Server to Windows 2000 Server For small networks that do not have Internet access, that do not use the Active Directory, that do not use routing, and that require only a basic installation For backward compatibility with particular applications

DLC Data Link Control (DLC) protocol: Enables communication with older IBM mainframes and minicomputers, and with some older HP print server cards

When to Use DLC To connect to IBM and other computers that use Systems Network Architecture (SNA) communications To connect to older peripheral devices, such as printers that use DLC

AppleTalk AppleTalk: A peer-to-peer protocol used in network communication between Macintosh computers Windows 2000 Server Services for Macintosh include: File Server for Macintosh (MacFile) Print Server for Macintosh (MacPrint) AppleTalk protocol

When to Use AppleTalk Use AppleTalk to enable Macintosh clients to connect to Windows 2000 Server

Binding Order Establishes the protocol that will be tried first in a network communication (or a communication with a network printer)

Troubleshooting Tip If network performance is slow and your network uses multiple protocols change the binding order

Network Planning Considerations Size and purpose of the organization Potential growth Proportion of mission-critical applications Role of the network to the mission of the organization

Network Planning Considerations Security needs Budget Internet and intranet requirements Interconnectivity requirements

Planning Tip Begin network planning by understanding: User needs Important business processes Current resources Potential growth

Considerations in Selecting the Right Protocol(s) Routing needs Size of the network in terms of connections Presence of Windows 2000 servers

Considerations in Selecting the Right Protocol(s) Presence of mainframes and other computers that use SNA Presence of NetWare servers Access to the Internet or intranets Presence of mission-critical and multimedia applications

The End