Protocols and Compatibility

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


100000110.11011110.1100101.00000101


converted to decimal (e.g., 134.22.101.005)

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

Protocols and Applications

in the TCP/IP Suite

Protocols and Applications

in the TCP/IP Suite

Protocols and Applications

in the TCP/IP Suite

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/NetBEUI

communication

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