Network Protocols

Network Protocols

Chapter 8

Release 16/7/2009

Chapter Objectives

List the different types of network protocols Identify the working of each network protocol Explain the functions of different protocols in TCP/IP

protocol suite Configure IPX/SPX on Windows XP Install NetBIOS/NetBEUI on Windows XP

Jetking Infotrain Ltd.

Release 16/7/2009

Recall

MAC address is a hardware address that is permanently embedded into NIC

When two nodes are connected by directly connecting cables, it is called direct cable connection

Two types of volt-ohm meters: Analog Digital

Function of a probe is to trace signal emitted by the tone generator


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Introducing Protocols Set of predefined rules used by devices in network

for data transfer Network Protocols:

NetBIOS/NetBEUI TCP/IP ARP/RARP ICMP/IGMP UDP IPX/SPX HDLC/SDLC


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NetBIOS/NetBEUI

Developed by IBM and later adopted by Microsoft Network Basic Input/Output System (NetBIOS) used

for communication within LAN Operates at Transport and Session layers of OSI

model NetBIOS Extended User Interface (NetBEUI) adds

capabilities to NetBIOS and an advanced version of NetBIOS used in MS Windows OS

Widely used in Ethernet, Token Ring and Windows NT networks


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NetBIOS Services Supports three distinct services: Name service for name

registration and resolution, Session service for connection oriented communication and datagram service for connectionless communication

NetBIOS Services

Name ServiceSession Service

Datagram Service


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Name Service

Implemented in Microsoft Windows as Windows Internet Name Service (WINS).

Provides means to application to register its NetBIOS name

NetBIOS names are 16 bytes length Service uses UDP port 137 Name Service functions include

Add Name Add Group Name Delete Name Find Name


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Session Service

Establishes session for data exchange between computers using TCP port 139

Session Establishment Process Session Termination Process


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Datagram Service

Uses the UDP port 138 and provides a connectionless and broadcast-oriented data communication between two devices.

Divides data in datagrams before sending Datagram service functions include:

Send Datagram Send Broadcast Datagram Receive Datagram Receive Broadcast Datagram


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NetBIOS Name Resolution

Used to map NetBIOS names to IP addresses Methods used to resolve names:

NetBIOS Name Cache NetBIOS Name Server (NBNS) Local Broadcast


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NetBEUI Enhanced version of NetBIOS Used by LAN manager, LAN server, Windows

for workgroups, Windows 95 and Windows NT Adapted to other protocols such as IPX or

TCP/IP as it does not support routing of messages to other networks


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TCP/IP

Two layer communication protocol used by Internet TCP provides connection-oriented reliable transport

service Divides the message into smaller packets called

segments IP is a connectionless and unreliable datagram

protocol and provides no error checking IP transfers data in the form of packets called

datagrams


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TCP/IP Protocol Suite

Designed before OSI model

Consists of five layers

Provides independent protocols at each layer


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Description of each layer - I

Physical and Data link layer – standard and proprietary protocols are supported by these layers.

Network layer – 1. IP – 2. ARP – 3. RARP – 4. ICMP – used to send query and error reporting

messages to the sender and not to correct them 5. IGMP – Uses class D IP address


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Description of each layer - II

Transport layer – 1. UDP – 2. TCP – divides data into segments each having

a sequence number 3. Stream Control Transmission Protocol (SCTP)

– multiple streams of data can be transmitted simultaneously. Used over wireless network and transmission of multimedia data. Supports voice over IP and combines the best features of TCP and UDP


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Description of each layer - III

Application layer – 1. SMTP – 2. FTP – 3. DNS – 4. SNMP – Based on client-server model NFS – Allows different Operating systems to

share files and disk storage TFTP – Uses UDP to upload or download files

and does not provide security features


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TCP Segment Format

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IPv4 Datagram Format


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IP Datagram Fragmentation

Fragmentation refers to breaking datagrams into pieces

Maximum Transfer Unit (MTU) is maximum amount of data that frame can carry

Datagram is fragmented when its size exceeds MTU of the network

Fragments follow different paths to reach destination


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Explain ARP/RARP from CBT


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ICMP/IGMP Internet Control Message Protocol (ICMP) provides

error reporting and query management mechanism ICMP handles problems occurring while packet

transmission Internet Group Message Protocol (IGMP) manages

multicasting and group membership of devices


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ICMP Message Types

Error Reporting

Destination Unreachable

Router Solicitation and Advertisement

Timestamp request and reply

Address MaskRequest and reply

Echo request and reply

Query

Source Quench

Time Exceeded

Redirection

Parameter Problem

ICMP Messages


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Error Reporting Messages

ICMP is used for error reporting not for error correcting1. Destination Unreachable – 2. Source Quench – used for flow control at network layer3. Time Exceeded - 4. Parameter Problem – if there is an ambiguity in the header part5. Redirection – if the host forwards datagram destined for some other network to wrong router


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Query Messages

Echo Request and Reply – Ping command Timestamp request and reply – Address Mask request and reply – If a host

knows the IP address but does not know the corresponding mask

Router Solicitation and Advertisement – Used to determine whether the routers in the network are working properly


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IGMP Message Types

IGMP Messages

QueryMembership

Report Leave Report

General Query Special Query


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UDP

User Datagram Protocol (UDP) provides connectionless process-to-process communication

UDP packets are called user datagrams. User Datagram Format:


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Explain UDP operation using CBT


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IPX/SPX

Novell NetWare system uses IPX/SPX as communication protocol within networks

IPX operates at Network layer for connectionless communication

SPX operates at Transport layer for connection-oriented communication

Together, IPX/SPX provides same services as TCP/IP


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IPX/SPX Protocol Suite


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IPX/SPX Naming Conventions IPX/SPX/NetBIOS Compatible Transport Protocol

(NWLink) uses two types of IPX network numbers for routing purposes: Internal network number – Mentioned as Internal

network number in NWLink IPX/SPX/NetBIOS Compatible Transport Protocol Properties dialog box

It’s a hexadecimal number with 1 to 8 digits (1 to FFFFFFFE)

External network number – Mentioned as Network number in Manual Frame Detection dialog box


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HDLC/SDLC

DLC protocols are two types: asynchronous and synchronous

High Level Data Link Control (HDLC) and Synchronous Data Link Control (SDLC) are bit-oriented synchronous protocols in which data frames are interpreted as series of bits

Both are useful for half-duplex and full-duplex communication

HP adopted DLC protocol for use by network printers Windows XP still support DLC


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HDLC Nodes and Link Configurations Types of HDLC nodes are:

Primary Station – transmits frames called commands to secondary stations

Secondary Station – send response frames to primary station

Combined Station Supported link configurations:

Unbalanced Balanced


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SDLC

Bit-oriented protocol invented by IBM and similar to HDLC

Only primary and secondary stations are used

Configurations

Point-to-Point Multipoint Loop Hub go-ahead


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Protocols at Different Layers

OSI Layers Protocols

Physical Layer No protocols defined

Data Link Layer HDLC, SDLC

Network Layer IP, ICMP, IGMP, ARP, RARP, IPX

Transport Layer NetBEUI, TCP, UDP, SPX

Session Layer NetBIOS, SAP, SMTP, FTP, DNS, SNMP,

Presentation Layer NCP, RIP, NLSP, SMTP, FTP, DNS, SNMP, NFS

Application Layer SMTP, DNS, SNMP, NFS, TFTP


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Summary - I

Network protocols are the set of predefined rules, used by the devices connected to network to communicate with each other

Different network protocols include NetBIOS/NetBEUI, TCP/IP and IPX/SPX

NetBIOS protocol is used for communication within a LAN and operates at the session layer of the OSI model

NetBIOS provides three types of services namely Name service, Session service and Datagram service

Name service allows an application to register its NetBIOS name in the network


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Summary - II

Two computers can establish a session for data transfer using the Session service which is a connection-oriented service

In the connectionless Datagram service, data is transferred in the form of small packets called datagrams

NetBIOS name resolution is used to map a NetBIOS names to an IP address. Methods used for resolution are, NetBIOS Name Server (NBNS), NetBIOS name cache and Local Broadcast

LMHOSTS file is a static file that resolves the names to IP address for applications running on the remote computer

TCP/IP is a five-layer protocol suite developed before the OSI model


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Summary - III

TCP is a connection-oriented, reliable and process-to-process transport layer protocol in the TCP/IP protocol suite

At TCP, data is divided into segments with each segment having sequence number for reassembly of the data at the destination

Connection establishment requires three-way handshaking; connection termination requires four-way handshaking process

IP is an unreliable connectionless protocol responsible for source-to-destination delivery

Packets in the IP layer are called datagrams which consist of data and header


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Summary - IV

Fragmentation is the division of a datagram into smaller units when size of the datagram exceeds MTU

ARP protocol is used to obtain the physical address of the device when its logical address is known

RARP protocol is used to obtain the logical address of the device when its physical address is known

ICMP protocol is used to send error and control messages. Two types of ICMP messages are Error-reporting messages and Query messages

Error reporting messages include Destination Unreachable, Source Quench, Time exceeded, Parameter Problem and Redirection


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Summary - V

Query messages include Echo Request and Reply, Timestamp Request and Reply, Address Mask Request and Reply and Router Solicitation and Advertisement

IGMP protocol is used to govern the management of multicast groups in a network. Three types of IGMP messages are Query, Membership Report and Leave Report

UDP protocol operates at the transport layer and provides connectionless and unreliable service

The UDP packet is called as user datagram which is encapsulated into an IP packet

Incoming and outgoing queues hold messages going to and from UDP


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Summary - VI

Novell NetWare operating system uses IPX/SPX protocol for communication within a network

IPX operates at the network layer and provides connectionless routing services using either RIP or NLSP

HDLC is a data link control protocol used for point-to-point communications over a serial links

Three types of devices used in HDLC are primary station, secondary station and combined station

HDLC supports three configuration modes: Normal Response Mode, Asynchronous Response Mode and Asynchronous Balanced Mode


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Network Protocols