Network Protocols

standguideNetworking and Communications

Oct 26, 2013 (3 years and 7 months ago)

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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

Transmission
Control
Protocol/Internet
Protocol (TCP/IP)


Suite of small,
specialized
protocols called
subprotocols

OSI Model

TCP/IP

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

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

Table 3
-
1: Commonly used TCP/IP classes

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 Microsoft
-
based 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