lmt 9 network protocols

8/14/2019 Lmt 9 Network Protocols

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Network Communicationsand Protocols

1AMIT Kr. BHARDWAJ, LMTSOM


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AMIT Kr. BHARDWAJ,LMTSOM

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Objectives

Explain the function of protocols in anetwork

Describe common protocol suites


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Protocols

Strictly speaking, protocols are therules and procedures forcommunicating

For two computers to communicate,they must speak the same language andagree on the rules of communication


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The Function of Protocols

As protocols serve their functions in theOSI model, they might work at one ormany layers

When a set of protocols works

cooperatively, its called a protocol stackor protocol suiteThe most common protocol stack is TCP/IP,

the Internet protocol suite IPX/SPX, used in older versions of Novell

NetWare, is disappearing as companiesupgrade to newer versions of NetWare

Levels of a protocol stack map to theirfunctions in the OSI model


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Connectionless VersusConnection-Oriented Protocols

Protocols that use connectionless deliveryplace data on the network and assume it willget through Connectionless protocols arent entirely reliable Are fast: little overhead, dont waste time

establishing/managing/tearing down connections Connection-oriented protocols are more

reliable and, consequently, slowerTwo computers establish a connection before data

transfer begins In a connection, data is sent in an orderly fashion

Ensures that all data is received and is accurate, orthat suitable error messages are generated


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Routable Versus NonroutableProtocols

The network layer (OSI) is responsible formoving data across multiple networks Routers are responsible for routing process

Protocol suites that function at Network

layer are routable or routed protocols;otherwise, they are called nonroutableTCP/IP and IPX/SPX are routable protocols An older and nearly obsolete protocol, NetBEUI,

is a nonroutable protocol that works well insmall networks, but its performance dropsconsiderably as a network grows


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Protocols in a LayeredArchitecture


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Protocols in a LayeredArchitecture (continued)


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Network Protocols

Some popular network protocols include:

Internet Protocol version 4 (IPv4 or simply IP)

Provides addressing and routing information

Internetwork Packet Exchange (IPX)

Novells protocol for packet routing and forwarding Belongs to the IPX/SPX protocol suite

Serves many of the same functions as TCP/IPs IP

Internet Protocol version 6 (IPv6)

A new version of IP thats being implemented on many currentnetworking devices and operating systems

Addresses some weaknesses of IPv4


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Transport Protocols

Transport protocols can be connection-oriented (reliable) or connectionless (best-effort) delivery Transmission Control Protocol (TCP)

Responsible for reliable data delivery in TCP/IP

Sequential Packet Exchange (SPX) Novells connection-oriented protocol used to

guarantee data delivery

NetBIOS/NetBEUI NetBIOS establishes/manages communications

between computers and provides naming services NetBEUI provides data transport services for these

communications


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Application Protocols

Application protocols provide services toclient applications

Simple Mail Transport Protocol (SMTP) in TCP/IP

File Transfer Protocol (FTP) in TCP/IP

Simple Network Management Protocol (SNMP) Manages and monitors network devices (TCP/IP)

NetWare Core Protocol (NCP)

Novells client shells and redirectors

AppleTalk File Protocol (AFP) Apples remote file-management protocol


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Common Protocol Suites

Because most protocols contain acombination of components, thesecomponents are usually bundled as a protocol

suiteTCP/IP

Dominates the networking arena to the point of makingmost of the other suites nearly obsolete

IPX/SPX

NetBIOS/NetBEUI

AppleTalk

T i i C t l


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Transmission ControlProtocol/Internet Protocol

(TCP/IP)


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TCP/IP Network LayerProtocols

Internet Protocol version 4 (IPv4) is a Networklayer protocol that provides source anddestination addressing and routing for the TCP/IPsuite Connectionless protocol; fast but unreliable

Internet Control Message Protocol (ICMP) isa Network layer protocol used to send error andcontrol messages between systems or devicesThe Ping utility uses ICMP to request a response from a

remote host to verify availability

Address Resolution Protocol (ARP) resolves

logical (IP) addresses to physical (MAC) addresses


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IP, ICMP, and ARP in Action


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IP, ICMP, and ARP in Action(continued)


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TCP/IP Transport LayerProtocols

Transmission Control Protocol (TCP) is theprimary Internet transport protocol

Connection oriented using a three-way handshake

Message fragmentation and reassembly

Uses acknowledgements to ensure that all data wasreceived and to provide flow control

User Datagram Protocol (UDP) is connectionless

Generally faster, although less reliable, than TCP Doesnt segment data or resequence packets

Doesnt use acknowledgements for reliability

Used by NFS and DNS


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TCP/IP Application LayerProtocols

Domain Name System (DNS)

Session layer name-to-address resolution protocol

Hypertext Transport Protocol (HTTP)

To transfer Web pages from Web server to browser

File Transfer Protocol (FTP)

For file transfer and directory and file manipulation Telnet

Remote terminal emulation; operates at layers 7-5

Simple Mail Transport Protocol (SMTP)

Operates at layers 7-5; provides messaging services


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IP Addressing

Logical addresses are 32 bits (4 bytes) long

Each byte is represented as an octet (decimal numberfrom 0 to 255)

Usually represented in dotted decimal notation E.g., 172.24.208.192

Address has two parts: network and host ID

E.g. 172.24.208.192 (172.24.0.0 and 208.192)

Categorized into ranges referred to as classes

Class system provides basis for determining which part ofaddress is the network and which is the host ID

The first octet of an address denotes its class


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Dynamic Host ConfigurationProtocol (DHCP)

Detailed configuration of devices, keeping track ofassigned addresses and to which machine they wereassigned, etc., is difficult in large networks

DHCP was developed to make this process easier

DHCP server must be configured with a block of availableIP addresses and their subnet masks

Clients must be configured to use DHCP

Broadcast request message is sent on boot

Client leases the address the server assigns to it

If no answer is received, in an APIPA-enabled OS, the computer assigns

itself an address (169.254.x.x)


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NetBIOS and NetBEUI


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IPX/SPX


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Summary

Many protocols are available for networkcommunications, each with itsstrengths/weaknesses

The TCP/IP protocol suite dominates network

communication in part due to its use on theInternet

IP addressing involves several concepts,including address classes, subnetting, andsupernetting

IPv6 will eventually replace IPv4 because itoffers several advantages: 128-bit addressspace, autoconfiguration, built-in security,and QoS

lmt 9 network protocols

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