chapter three

Chapter ThreeChapter ThreeNetwork Network

ProtocolsProtocols

Introduction to ProtocolsIntroduction to Protocols

ProtocolProtocol Rules network uses to transfer dataRules network uses to transfer data Protocols that can span more than one LAN Protocols that can span more than one LAN

segment are segment are routableroutableSNA & DLC becoming outdated due to non-SNA & DLC becoming outdated due to non-routabilityroutability

Multiprotocol networkMultiprotocol network Network using more than one protocolNetwork using more than one protocol

TCP/IPTCP/IP

Transmission Transmission Control Control Protocol/Internet Protocol/Internet Protocol (TCP/IP)Protocol (TCP/IP)

Suite of small, Suite of small, specialized specialized protocols called protocols called subprotocolssubprotocols

OSI Model TCP/IP

Figure 3-1: TCP/IP compared to the OSI Model

The TCP/IP The TCP/IP CoreCore Protocols Protocols

Certain subprotocols of TCP/IP Certain subprotocols of TCP/IP suitesuite Operate in Transport or Network layers of OSI Operate in Transport or Network layers of OSI

ModelModel Provide basic services to protocols in other Provide basic services to protocols in other

layers of TCP/IPlayers of TCP/IP

TCP and IP are most significant core TCP and IP are most significant core protocols in TCP/IP suiteprotocols in TCP/IP suite

Internet Protocol (IP)Internet Protocol (IP)

Provides information about how and where Provides information about how and where data should be delivereddata should be delivered

Subprotocol that enables TCP/IP to Subprotocol that enables TCP/IP to internetworkinternetwork To To internetworkinternetwork is to traverse more than one is to traverse more than one

LAN segment and more than one type of LAN segment and more than one type of network through a routernetwork through a router

In an internetwork, the individual networks that In an internetwork, the individual networks that are joined together are called are joined together are called subnetworks subnetworks (or (or subnets)subnets)


IP datagramIP datagram IP portion of IP portion of

TCP/IP TCP/IP frame that frame that acts as an acts as an envelope for envelope for datadata

Contains Contains information information necessary necessary for routers to for routers to transfer data transfer data between between subnetssubnets

Figure 3-2: Components of an IP datagram


VersionVersion IPv4 – current version used for 20 yearsIPv4 – current version used for 20 years IPv6 – in processIPv6 – in process

Time to live (TTL) – max time, in seconds, Time to live (TTL) – max time, in seconds, that a datagram can remain on the that a datagram can remain on the network before it is discardednetwork before it is discarded Also corresponds to # of router hopsAlso corresponds to # of router hops


IP is an unreliable, connectionless IP is an unreliable, connectionless protocol, which means it does not protocol, which means it does not guarantee delivery of dataguarantee delivery of data ConnectionlessConnectionless

Allows protocol to service a request without Allows protocol to service a request without requesting verified session and without requesting verified session and without guaranteeing delivery of dataguaranteeing delivery of data

Transport Control Protocol (TCP)Transport Control Protocol (TCP)

TCPTCP Provides reliable data delivery servicesProvides reliable data delivery services Connection-orientedConnection-oriented subprotocol subprotocol

Requires establishment of connection between Requires establishment of connection between communicating nodes before protocol will transmit communicating nodes before protocol will transmit datadata

TCP segmentTCP segment Holds TCP data fieldsHolds TCP data fields Becomes encapsulated by IP datagramBecomes encapsulated by IP datagram

Transport Control Protocol (TCP)Transport Control Protocol (TCP)

PortPort Address on host where application makes itself available to Address on host where application makes itself available to

incoming dataincoming data

Figure 3-3: A TCP

segment

Additional Core Protocols of the Additional Core Protocols of the TCP/IP SuiteTCP/IP Suite

User Datagram Protocol (UDP)User Datagram Protocol (UDP) Connectionless transport serviceConnectionless transport service Lack of sophistication makes it more efficient than TCPLack of sophistication makes it more efficient than TCP

Live audio/video transmissions over the InternetLive audio/video transmissions over the Internet

Internet Control Message Protocol (ICMP)Internet Control Message Protocol (ICMP) Notifies sender of an error in transmission process and that Notifies sender of an error in transmission process and that

packets were not deliveredpackets were not delivered Sits between IP & TCP in Internet layer of TCP/IP modelSits between IP & TCP in Internet layer of TCP/IP model

Used by PING diagnostic toolUsed by PING diagnostic tool

Address Resolution Protocol (ARP)Address Resolution Protocol (ARP) Obtains MAC address of host or nodeObtains MAC address of host or node Creates local database mapping MAC address to host’s IP Creates local database mapping MAC address to host’s IP

addressaddress

TCP/IP Application Layer TCP/IP Application Layer ProtocolsProtocols

These protocols work over TCP (or UDP) and IP:These protocols work over TCP (or UDP) and IP:Telnet Telnet Used to log on to remote hosts using TCP/IP protocol suite Used to log on to remote hosts using TCP/IP protocol suite

File Transfer Protocol (FTP)File Transfer Protocol (FTP) Used to send and receive files via TCP/IPUsed to send and receive files via TCP/IP

Simple Mail Transfer Protocol (SMTP)Simple Mail Transfer Protocol (SMTP) Responsible for moving messages from one e-mail server Responsible for moving messages from one e-mail server

to another, using the Internet and other TCP/IP-based to another, using the Internet and other TCP/IP-based networksnetworks

Simple Network Management Protocol (SNMP)Simple Network Management Protocol (SNMP) Manages devices on a TCP/IP networkManages devices on a TCP/IP network

Addressing in TCP/IPAddressing in TCP/IP

IP AddressIP Address Logical address used in TCP/IP networkingLogical address used in TCP/IP networking Unique 32-bit numberUnique 32-bit number

Divided into four groups of Divided into four groups of octetsoctets (8-bit bytes) (8-bit bytes) that are separated by periodsthat are separated by periods

IP addresses are assigned and used IP addresses are assigned and used according to very specific parametersaccording to very specific parameters

Example: 144.92.43.178Example: 144.92.43.178


Though 8 bits have 256 possible combinations, only the Though 8 bits have 256 possible combinations, only the numbers 1 through 254 are used to identify networks numbers 1 through 254 are used to identify networks and hostsand hosts

Numbers 0 and 255 are reserved for Numbers 0 and 255 are reserved for broadcastsbroadcasts Broadcast are transmissions to all stations on a networkBroadcast are transmissions to all stations on a network

Table 3-1: Commonly used TCP/IP classes


Group AGroup A Only 126 available – used/reserved for large Only 126 available – used/reserved for large

corporations or governmentscorporations or governments Share the first octet (1-126)Share the first octet (1-126) i.e. i.e. 2323.78.110.109, .78.110.109, 2323.164.32.97.164.32.97

Group BGroup B Share the first two octets (128-191)Share the first two octets (128-191) i.e. i.e. 168.34168.34.88.29, .88.29, 168.34168.34.55.41.55.41

Group CGroup C Share the first three octets (192-223)Share the first three octets (192-223) i.e i.e 204.139.118204.139.118.7, .7, 204.139.118204.139.118.14.14


Loopback addressLoopback address IP address reserved for communicating from a IP address reserved for communicating from a

node to itselfnode to itself Value of the loopback address is always Value of the loopback address is always

127.0.0.1 127.0.0.1 (try it)(try it)

Internet Corporation for Assigned Names and Internet Corporation for Assigned Names and Numbers (ICANN) – formerly InterNICNumbers (ICANN) – formerly InterNIC Non-profit organization currently designated by Non-profit organization currently designated by

U.S. government to maintain and assign IP U.S. government to maintain and assign IP addressesaddresses


FirewallFirewall Specialized device (typically a router)Specialized device (typically a router) Selectively filters or blocks traffic between Selectively filters or blocks traffic between

networksnetworks May be strictly hardware-based or may involve a May be strictly hardware-based or may involve a

combination of hardware and softwarecombination of hardware and software

HostHost Computer connected to a network using the Computer connected to a network using the

TCP/IP protocolTCP/IP protocol


IP address data are sent across the network in IP address data are sent across the network in binary formbinary formIn IP address 131.127.3.22, to convert the first In IP address 131.127.3.22, to convert the first octet (131) to a binary number:octet (131) to a binary number: On Windows 2000, click On Windows 2000, click StartStart, point to , point to ProgramsPrograms, ,

point to point to AccessoriesAccessories, then click , then click CalculatorCalculator Click Click ViewView, then click , then click ScientificScientific (make sure (make sure Dec Dec

option buttonoption button is selected) is selected) Type Type 131131, then click , then click Bin option buttonBin option button

The binary equivalent of number 131, 10000011, appears The binary equivalent of number 131, 10000011, appears in the display windowin the display window


Static IP addressStatic IP address IP address manually assigned to a deviceIP address manually assigned to a device

Dynamic Host Configuration Protocol Dynamic Host Configuration Protocol (DHCP)(DHCP) Application layer protocolApplication layer protocol Manages dynamic distribution of IP addresses Manages dynamic distribution of IP addresses

on a networkon a network

Viewing Current IP InformationViewing Current IP Information

Figure 3-4: Example of an IP

configuration window

Viewing Current IP InformationViewing Current IP Information

Figure 3-5: IP address

information on a

Windows 2000

workstation

Addresses and NamesAddresses and Names

In addition to using IP addresses, TCP/IP In addition to using IP addresses, TCP/IP networks use names for networks and networks use names for networks and hostshosts Each host requires a host nameEach host requires a host name Each network requires a network name, also Each network requires a network name, also

called a called a domain namedomain name Together, host name and domain name Together, host name and domain name

constitute the constitute the fully qualified domain name fully qualified domain name (FQDN)(FQDN)

IPX/SPXIPX/SPX

Internetwork Packet Internetwork Packet Exchange/SequenceExchange/Sequenced Packet Exchange d Packet Exchange (IPX/SPX)(IPX/SPX) Protocol originally Protocol originally

developed by Xeroxdeveloped by Xerox Modified and adopted Modified and adopted

by Novell in the by Novell in the 1980s for the 1980s for the NetWare network NetWare network operating systemoperating system

Figure 3-6: IPX/SPX compared to the OSI Model

IPX/SPX Core ProtocolsIPX/SPX Core ProtocolsInternetwork Packet Exchange (IPX)Internetwork Packet Exchange (IPX)

Operates at Network layer of OSI ModelOperates at Network layer of OSI Model Provides routing and internetworking servicesProvides routing and internetworking services Similar to IP in TCP/IP suiteSimilar to IP in TCP/IP suite Socket – logical address assigned to a specific processSocket – logical address assigned to a specific process

Figure 3-7: Components

of an IPX datagram

IPX/SPX Core ProtocolsIPX/SPX Core Protocols

Sequenced Packet Exchange (SPX)Sequenced Packet Exchange (SPX) Belongs to Transport layer of OSI ModelBelongs to Transport layer of OSI Model Works in tandem with IPX to ensure data are Works in tandem with IPX to ensure data are

received:received:WholeWhole

In sequenceIn sequence

Error freeError free

Similar to TCPSimilar to TCP


Figure 3-8: SPX packet encapsulated by an IPX datagram


Service Advertising Protocol (SAP)Service Advertising Protocol (SAP) Works in Application, Presentation, Session, Works in Application, Presentation, Session,

and Transport layers of OSI Modeland Transport layers of OSI Model Runs directly over IPXRuns directly over IPX Used by NetWare servers and routersUsed by NetWare servers and routers to to

advertiseadvertise to entire network which services to entire network which services they can providethey can provide

Can lead to unnecessary network trafficCan lead to unnecessary network traffic


NetWare Core Protocol (NCP)NetWare Core Protocol (NCP) Works within Presentation and Sessions Works within Presentation and Sessions

layers of OSI Modellayers of OSI Model Works over IPXWorks over IPX Handles requests for services Handles requests for services between clients between clients

and serversand servers

Addressing in IPX/SPXAddressing in IPX/SPX

IPX addressIPX address Address assigned to a device on an IPX/SPX Address assigned to a device on an IPX/SPX

networknetwork Contains two parts:Contains two parts:

Network address (Network address (external network numberexternal network number)) Established Network Admin when network is installedEstablished Network Admin when network is installed

Node addressNode address NIC MAC addressNIC MAC address

Example (8.12):Example (8.12): 000008A2:0060973E97F3000008A2:0060973E97F3

NetBIOS and NetBEUINetBIOS and NetBEUI

Network Basic Input Output System Network Basic Input Output System (NetBIOS)(NetBIOS) Originally designed by IBM to provide Originally designed by IBM to provide

Transport and Session layer servicesTransport and Session layer services Adopted by Microsoft as its foundation Adopted by Microsoft as its foundation

protocolprotocol Microsoft added Application layer Microsoft added Application layer

component called component called NetBEUINetBEUI

NetBIOS and NetBEUINetBIOS and NetBEUI

NetBIOS Enhanced User InterfaceNetBIOS Enhanced User Interface FastFast and and efficientefficient protocol protocol Consumes few network resourcesConsumes few network resources Provides excellent error correctionProvides excellent error correction Requires little configurationRequires little configuration Can handle Can handle only 254only 254 connections connections Does not allow for good securityDoes not allow for good security By itself, it is By itself, it is not routablenot routable

NetBIOS and NetBEUI Compared NetBIOS and NetBEUI Compared to the OSI Modelto the OSI Model

Figure 3-9: NetBIOS/NetBEUI compared to the OSI Model

NetBIOS AddressingNetBIOS Addressing

Figure 3-10: Identification

tab in Network properties

AppleTalkAppleTalk

Protocol suite used to interconnect Protocol suite used to interconnect MacintoshMacintosh computerscomputersOriginally designed to support peer-to-peer Originally designed to support peer-to-peer networking among Macintoshesnetworking among MacintoshesCan now be routed between network segments Can now be routed between network segments and integrated with NetWare- and Microsoft-and integrated with NetWare- and Microsoft-based networksbased networksAppleTalk networks are separated into logical AppleTalk networks are separated into logical groups of computers called groups of computers called AppleTalk zonesAppleTalk zonesApple has begun supporting TCP/IPApple has begun supporting TCP/IP

AppleTalk and OSI ModelAppleTalk and OSI Model

Figure 3-11: AppleTalk protocol compared to OSI Model

Addressing in AppleTalkAddressing in AppleTalk

AppleTalk node IDAppleTalk node ID Unique 8-bit or 16-bit number identifying a Unique 8-bit or 16-bit number identifying a

computer on an AppleTalk networkcomputer on an AppleTalk network

AppleTalk network numberAppleTalk network number Unique 16-bit number identifying the network Unique 16-bit number identifying the network

to which a node is connectedto which a node is connected

Installing ProtocolsInstalling Protocols

After installing protocols, they must be After installing protocols, they must be binded to NICs and services they run on or binded to NICs and services they run on or withwith BindingBinding

Process of assigning one network component to Process of assigning one network component to work with anotherwork with another

chapter three

Documents

connectionless protocol

tcpip networkaddressing

tcpip networkingunique

ip tcp

specialized protocols

significant core protocols

protocolsprotocolrules

type of network