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Chapter Three
Network
Protocols
Objectives
Identify characteristics of TCP/IP, IPX/SPX,
NetBIOS, and AppleTalk
Understand position of network protocols in OSI
Model
Identify core protocols of each protocol suite and
its functions
Understand each protocol’s addressing scheme
Install protocols on Windows 98 and Windows
2000 clients
Introduction to Protocols
Protocol


Rules network uses to transfer data
Protocols that can span more than one LAN
segment are routable
Multiprotocol network

Network using more than one protocol
TCP/IP
OSI Model
TCP/IP
Transmission
Control
Protocol/Internet
Protocol (TCP/IP)

Suite of small,
specialized
protocols called
subprotocols
Figure 3-1: TCP/IP compared to the OSI Model
TCP/IP Compared to the
OSI Model
Application layer roughly corresponds to
Session, Application, and Presentation layers of
OSI Model
Transport layer roughly corresponds to
Transport layers of OSI Model
Internet layer is equivalent to Network layer of
OSI Model
Network Interface layer roughly corresponds to
Data Link and Physical layers of OSI Model
The TCP/IP Core Protocols
Certain subprotocols of TCP/IP suite


Operate in Transport or Network layers of OSI
Model
Provide basic services to protocols in other
layers of TCP/IP
TCP and IP are most significant core
protocols in TCP/IP suite
Internet Protocol (IP)
Provides information about how and where
data should be delivered
Subprotocol that enables TCP/IP to
internetwork


To internetwork is to traverse more than one
LAN segment and more than one type of
network through a router
In an internetwork, the individual networks that
are joined together are called subnetworks
Internet Protocol (IP)
IP datagram


IP portion of
TCP/IP
frame that
acts as an
envelope for
data
Contains
information
necessary
for routers to
transfer data
between
subnets
Figure 3-2: Components of an IP datagram
Internet Protocol (IP)
IP is an unreliable, connectionless
protocol, which means it does not
guarantee delivery of data

Connectionless
Allows protocol to service a request without
requesting verified session and without
guaranteeing delivery of data
Transport Control Protocol (TCP)
TCP

Provides reliable data delivery services

Connection-oriented subprotocol
Requires establishment of connection between
communicating nodes before protocol will transmit
data
TCP segment


Holds TCP data fields
Becomes encapsulated by IP datagram
Transport Control Protocol (TCP)
Port

Address on host where application makes itself available to
incoming data
Figure 3-3:
A TCP
segment
Additional Core Protocols of the
TCP/IP Suite
User Datagram Protocol (UDP)

Connectionless transport service
Internet Control Message Protocol (ICMP)

Notifies sender of an error in transmission
process and that packets were not delivered
Address Resolution Protocol (ARP)


Obtains MAC address of host or node
Creates local database mapping MAC address to
host’s IP address
TCP/IP Application Layer
Protocols
Telnet

Used to log on to remote hosts using TCP/IP protocol suite
File Transfer Protocol (FTP)

Used to send and receive files via TCP/IP
Simple Mail Transfer Protocol (SMTP)

Responsible for moving messages from one e-mail server
to another, using the Internet and other TCP/IP-based
networks
Simple Network Management Protocol (SNMP)

Manages devices on a TCP/IP network
Addressing in TCP/IP
IP Address


Logical address used in TCP/IP networking
Unique 32-bit number
Divided into four groups of octets (8-bit bytes)
that are separated by periods

IP addresses are assigned and used
according to very specific parameters
Addressing in TCP/IP
Table 3-1: Commonly used TCP/IP classes
Though 8 bits have 256 possible combinations, only the
numbers 1 through 254 are used to identify networks
and hosts
Numbers 0 and 255 are reserved for broadcasts

Broadcast are transmissions to all stations on a network
Addressing in TCP/IP
Loopback address


IP address reserved for communicating from a
node to itself
Value of the loopback address is always
127.0.0.1
Internet Corporation for Assigned Names and
Numbers (ICANN)

Non-profit organization currently designated by
U.S. government to maintain and assign IP
addresses
Addressing in TCP/IP
Firewall



Specialized device (typically a router)
Selectively filters or blocks traffic between
networks
May be strictly hardware-based or may involve a
combination of hardware and software
Host

Computer connected to a network using the
TCP/IP protocol
Addressing in TCP/IP
In IP address 131.127.3.22, to convert the
first octet (131) to a binary number:



On Windows 2000, click Start, point to
Programs, point to Accessories, then click
Calculator
Click View, then click Scientific (make sure
Dec option button is selected)
Type 131, then click Bin option button
The binary equivalent of number 131, 10000011,
appears in the display window
Addressing in TCP/IP
Static IP address

IP address manually assigned to a device
Dynamic Host Configuration Protocol
(DHCP)


Application layer protocol
Manages dynamic distribution of IP addresses
on a network
Viewing Current IP Information
Figure 3-4:
Example of an IP
configuration
window
Viewing Current IP Information
Figure 3-5:
IP address
information
on a
Windows
2000
workstation
Addresses and Names
In addition to using IP addresses, TCP/IP
networks use names for networks and
hosts



Each host requires a host name
Each network requires a network name, also
called a domain name
Together, host name and domain name
constitute the fully qualified domain name
(FQDN)
IPX/SPX
Internetwork Packet
Exchange/Sequence
d Packet Exchange
(IPX/SPX)


Protocol originally
developed by Xerox
Modified and adopted
by Novell in the
1980s for the
NetWare network
operating system
Figure 3-6: IPX/SPX compared
to the OSI Model
IPX/SPX Core Protocols
Internetwork Packet Exchange (IPX)



Operates at Network layer of OSI Model
Provides routing and internetworking services
Similar to IP in TCP/IP suite
Figure 3-7:
Components
of an IPX
datagram
IPX/SPX Core Protocols
Sequenced Packet Exchange (SPX)


Belongs to Transport layer of OSI Model
Works in tandem with IPX to ensure data are
received:
Whole
In sequence
Error free
IPX/SPX Core Protocols
Figure 3-8: SPX packet encapsulated by an IPX datagram
IPX/SPX Core Protocols
Service Advertising Protocol (SAP)



Works in Application, Presentation, Session,
and Transport layers of OSI Model
Runs directly over IPX
Used by NetWare servers and routers to
advertise to entire network which services
they can provide
IPX/SPX Core Protocols
NetWare Core Protocol (NCP)



Works within Presentation and Sessions
layers of OSI Model
Works over IPX
Handles requests for services between clients
and servers
Addressing in SPX/IPX
IPX address


Address assigned to a device on an IPX/SPX
network
Contains two parts:
Network address (external network number)
Node address
NetBIOS and NetBEUI
Network Basic Input Output System
(NetBIOS)



Originally designed by IBM to provide
Transport and Session layer services
Adopted by Microsoft as its foundation
protocol
Microsoft added Application layer
component called NetBEUI
NetBIOS and NetBEUI
NetBIOS Enhanced User Interface






Fast and efficient protocol
Consumes few network resources
Provides excellent error correction
Requires little configuration
Can handle only 254 connections
Does not allow for good security
NetBIOS and NetBEUI Compared
to the OSI Model
Figure 3-9: NetBIOS/NetBEUI compared to the OSI Model
NetBIOS Addressing
Figure 3-10:
Identification
tab in Network
properties
AppleTalk
Protocol suite used to interconnect Macintosh
computers
Originally designed to support peer-to-peer
networking among Macintoshes
Can now be routed between network segments
and integrated with NetWare- and Microsoftbased networks
AppleTalk networks are separated into logical
groups of computers called AppleTalk zones
AppleTalk and OSI Model
Figure 3-11: AppleTalk protocol compared to OSI Model
AppleTalk Subprotocols
AppleShare
AppleTalk Filing Protocol (AFP)
AppleTalk Session Protocol (ASP)
AppleTalk Transaction Protocol (ATP)
AppleTalk Subprotocols
Name Binding Protocol (NBP)
Routing Table Maintenance Protocol
(RTMP)
Zone Information Protocol (ZIP)
Datagram Delivery Protocol (DDP)
Addressing in AppleTalk
AppleTalk node ID

Unique 8-bit or 16-bit number identifying a
computer on an AppleTalk network
AppleTalk network number

Unique 16-bit number identifying the network
to which a node is connected
Installing Protocols
After installing protocols, they must be
binded to NICs and services they run on or
with

Binding
Process of assigning one network component to
work with another
Chapter Summary
Protocols define standards for
communication between nodes on a
network
Protocols vary in speed, transmission
efficiency, utilization of resources, ease
of setup, compatibility, and ability to
travel between one LAN segments
TCP/IP is becoming most popular
network protocol
Chapter Summary
TCP/IP suite of protocols can be divided into
four layers roughly corresponding to seven
layers of OSI Model
Operating in Transport or Network layers of
OSI Model, TCP/IP core protocols provide
communications between hosts on a network
Each IP address is a unique 32-bit number,
divided into four groups of octets separated
by periods
Chapter Summary
Every host on a network must have a unique
number
Internetworking Packet Exchange/Sequenced
Packet Exchange (IPX/SPX) is a protocol
originally developed by Xerox then modified
and adopted by Novell in the 1980s for its
NetWare network operating system
Core protocols of IPX/SPX provide services
at Transport and Network layers of OSI
Model
Chapter Summary
Addresses on an IPX/SPX network are called
IPX addresses
Network Basic Input Output System
(NetBIOS) was originally developed by IBM
to provide Transport and Session layer
services
Microsoft adopted NetBIOS as its foundation
protocol, then added an Application layer
component called NetBIOS Enhanced User
Interface (NetBEUI)
Chapter Summary
To transmit data between network nodes,
NetBIOS needs to know how to reach each
workstation

Each workstation must have a NetBIOS name
AppleTalk is the the protocol suite used to
interconnect Macintosh computers
An AppleTalk network is separated into
logical groups of computers called AppleTalk
zones
Chapter Summary
Though Apple has improved AppleTalk’s ability
to use different network models and span
network segments, it remains unsuited to large
LANs or WANs
In addition to zone names, AppleTalk uses node
IDs and network numbers to identify computers
on a network
Though some protocols (such as NetBIOS)
require no configuration after installation, others
(such as TCP/IP) do require configuration