2. protocols and standards

7/31/2019 2. Protocols and Standards

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Protocols and Standards


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Objectives

Identify a MAC address

Understand Networking Protocol Understand Standards and the OSI Reference

Model Identify seven layers of the OSI Model and their

functions Differentiate between network protocols Identify the OSI layers at which network

components work Explain the protocols within TCP/IP Define function of TCP/UDP ports Identify well-known ports


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Objectives contd..

Identify the purpose of certain network services

Identify IP Addressing Explain the purpose of subnetting, subnet mask

and default gateways Differentiate between Public and Private

Networks Explain the basic characteristics of certain WAN

technologies Define the function of remote access protocols

and services Explain security protocols Explain Kerberos Authentication for Microsoft

Windows Server 2003


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MAC Address

MAC (Media Access Control) address is used to uniquelyidentify a node of a network.

A MAC address is also known as an Ethernet address,

hardware address, physical address.MAC addresses can be hard-coded into circuitry or storedin read-only memory (ROM), and they can be configuredusing vendor-supplied software.


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WINDOWS 2003 Server

Click on the Start Button Click on All Programs Next, click on Accessories, and then on

Command Prompt

Once a small black window appears, type inipconfig/all Locate the number to the right of Physical

Address. This is your MAC address


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WINDOWS 2003 Server contd..

Physical (MAC) address displayed under Windows 2003 Server


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In real world, if one wants to communicate successfullywith another person a certain protocol must be followed,i.e. same language should be used and while one personspeaks the other has to listen and vice versa.

This is the analogy of protocol followed by one computer tocommunicate with another.

A protocol may be defined as a set of rules governing the

exchange of data between two entities.

Networking Protocol


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It has long been accepted in the communications industrythat standards are required to govern the physical,electrical, and procedural characteristics of communicationequipment.

A standard is a prescribed set of rules, conditions, orrequirements concerning definition of terms; classificationof components; specification of materials, performance, oroperations; delineation of procedures; or measurement of

quantity and quality in describing materials, products,systems, services or practices.

Standards


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The OSI Reference Model

ISO (International Standards Organization) has promotedthe Open Systems Interconnection (OSI) model.

The purpose of this International Standard ReferenceModel is to provide a common basis for the coordination ofdevelopment of standards for the purpose of systemsinterconnection, while allowing existing standards to beplaced into perspective within the overall Reference Model.

Standard provides a conceptual and functional framework.


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The OSI LayersThe OSI model categorizes the various processes needed

in a communications session into seven distinct functionallayers.

The seven layers of OSI Model are as follows:

Physical Data Link Network Transport

Session Presentation Application


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Physical Layer

The physical layer is concerned with transmission of

unstructured bit stream over physical link.

It deals with the mechanical, electrical and proceduralcharacteristics to establish, maintain and deactivate the

physical link.

This is bottom layer of OSI model and is responsible for thetransmission of bit stream from one node to another.

Similarly, it passes to the Data Link Layer any datareceived from the physical medium.

The OSI Layers contd..


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Data Link Layer

The data link layer provides reliable transfer of data acrossthe physical link.

The Data Link layer is responsible for detecting andcorrecting any errors resulting in frames not reaching the

destination or becoming damaged and unusable during thetransmit.

The Data Link Layer takes the help of Layer 1 below and

provides the service to the Network Layer (Layer 3).

It provides end-to-end validity of the data being transmitted.



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Network Layer

The network layer provides upper layers withindependence from the data transmission and switchingtechnologies used to connect systems.

It establishes network connection and is responsible forestablishing the route to be used between the originatingand destination nodes.

The Network Layer is responsible for establishing the

connection to the node identified in the packet.



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Transport Layer

The transport layer provides reliable, transparent transfer

of data between end points and provides end-to-end errorrecovery and flow control.

It provides reliable virtual circuit for upper layers and

sequencing of packets.

At the receiving node, these fragments need to beassembled into the proper sequence.

The Transport layer provides these services and ensuresthe reliability of the packet.



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Session Layer

The session layer provides the control structure for

communication between applications.

It establishes, manages and terminates connections(sessions) between cooperating applications.

Presentation Layer

The presentation layer performs generally usefultransformations on data to provide a standardized

application interface and to provide commoncommunications services; for example: encryption, textcompression, reformatting, code conversion etc.



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Application Layer

The application layer provides services to the users of the

OSI environment; for example: transaction server, filetransfer protocol, network management.

It is the top layer in OSI model and provides the interface

between applications and the network.

Popular Protocols

Some of the most popular protocols are TCP/IP, IPX/SPX,NETBEUI and AppleTalk.


P l P l d


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TCP/IP

The IP component provides routing from the department tothe enterprise network, then to regional networks andfinally to the global Internet.

While IP (Internet Protocol) takes care of handling the

actual delivery of data, TCP takes care of individual units ofdata (called packets).

This design allows the construction of very large networks

with less central management.

Popular Protocols contd..

P l P l d


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IPX/SPX

IPX (Internetwork Packet Exchange) and SPX (SequencedPacket Exchange) are protocols developed by Novell andare used in NetWare based Networks.

They are based on protocols used in Xerox's XNS networkarchitecture.

IPX is a connection less protocol that works at networklayer of OSI Model.


P l P t l td


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NetBEUI

NetBIOS Extended User Interface also known as NetBEUI.

NetBEUI was mainly extended as a basic protocol tosupport NETBIOS, the windows standard for workstationnaming, communication and sharing. NetBEUI is used forworkgroup-size local area networks (LANs) with up to 200

stations.

NetBEUI was the primary protocol for LAN Manager andWindows for Workgroups.

It defines a framing mechanism at the transport layer andimplements the LLC2 protocol of the Open SystemsInterconnection (OSI) reference model for networking.


P l P t l td


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AppleTalk

AppleTalk enables users to share folders and printers for

access by other network users.

AppleTalk is a legacy technology that has been largelyreplaced by Apple Open Transport, which supports

AppleTalk, TCP/IP, and other popular network protocols.

AppleTalk is a workgroup-level networking technology thatsupports up to 254 network nodes per physical network.

AppleTalk is a suite of networking protocols that worktogether to provide file and print sharing services toMacintosh networks.



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How TCP/IP protocol worksWhen the application needs to send a large junk of data, it

is the responsibility of the TCP layer to fragment this intosmaller, manageable packets.

It is the responsibility of the TCP to ensure that the packetsof data are fragmented and transmitted. IP takes care of

routing the data packets so that it reaches its destination.

These packets may traverse through different parts andreach the destination in different order.

The TCP at the receiving end assembles it in the properorder and passes it to the application level at thedestination.


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Layers of TCP/IPTCP/IP consists of five layers, which include:

Application Layer

The Application layer provides the ability to access theservices of the other layers and defines the protocols that

used to exchange data.

There are many Application layer protocols and newprotocols are still evolving.

Access layer Internet layer Transport layer Application Layer

A li ti L td


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FTP: FTP (File Transfer Protocol) permits files to betransferred from one computer to another using a TCP

connection. FTP uses port 20 or 21.

TELNET: Telnet is the TCP/IP protocol for remote logon.TELNET uses port 23.

SMTP: SMTP (Simple Mail Transfer Protocol) provides thebasis for a network electronic mail facility.HTTP: HTTP (Hypertext transfer protocol) facilitates theviewing of multimedia files from the World Wide Web.

Application Layer contd..

Application Layer contd


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TFTP: TFTP is used for reading and writing files. It doesnot support directory service of user authorization.

S-HTTP: Secure HTTP (S-HTTP) provides securecommunication mechanisms between an HTTP client-server pair in order to enable spontaneous commercial

transactions for a wide range of applications.

SNMP: SNMP (Simple Network Management Protocol) is asimple protocol that gives the architecture specification anddefines messages related to network management.

POP3: The Post Office Protocol version 3 (POP3) isintended to permit a workstation to dynamically access amaildrop on a server host.


Application Layer contd


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IMAP4: The Internet Message Access Protocol, Version

4rev1 (IMAP4) allows a client to access and manipulateelectronic mail messages on a server.

NTP: The Network Time Protocol (NTP) is a timesynchronization system for computer clocks through the

Internet network.



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Transport Layer

This layer provides service to the Application Layer.

The Transport layer is responsible for providing theApplication layer with session and datagramcommunication services.

TCP

The TCP is responsible for verifying the correct delivery ofdata from client to server.

TCP adds support to detect errors or lost data and totrigger retransmission until the data is correctly andcompletely received.

Transport Layer contd


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UDP

UDP (User Datagram Protocol) like TCP facilitates thetransmission of data streams (e.g. a complete emailmessage) between applications running on different hosts.

Unlike TCP, UDP does not divide its data packets nor doesit provide sequencing of packets.

Transport Layer contd..


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Internet layer

This layer is primarily responsible for addressing and

routing packets between hosts.

IP is a connectionless, unreliable datagram protocolprimarily responsible for addressing and routing packets

between hosts

IP

Internet Protocol is implemented in each endpoint

computer and in every gateway. IP running in a hostcomputer accepts data in segments from TCP and sendsthem out across the internet.


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Network Components

Basic network components are:

Cables Network Adapter Cards Hubs Switching Hubs

Cables: The two most popular types of network cablingare twisted-pair (also known as 10BaseT) and thin coax(also known as 10Base2).

Network Adapter Card: A network computer isconnected to the network cabling with a networkinterface card, (also called a "NIC", "nick", or networkadapter).

Network Components contd


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Hub: The central connecting device is called a hub. A

hub is a box that is used to gather groups of PCstogether at a central location with 10BaseT cabling.

Switching Hub: The Switching hub, sometimes called a"Switch" is a more advanced unit over the basic hub.

Network Components contd..


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Data Link Layer

The data link layer is the second last layer in the stack.

The two major protocols utilized by Data Link layer are:ARP (Address Resolution Protocol) and RARP (ReverseAddress resolution Protocol).

Data Link Layer is composed of Network hardware anddevice drivers. The common technologies used in LAN areEthernet and Token Ring.

ARP: ARP is a protocol used for converting an IP addressto the actual address of the computer that is recognized inthe local network.

Data Link Layer contd


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RARP: RARP converts physical network addresses into IPaddresses.

SLIP and PPP are two protocols that allow two computersto communicate using a serial interface.

Data Link Layer contd..

Physical LayerThe Physical Layer is the lower-most layer in TCP/IPprotocol.

This layer deals with the Hardware part, through whichdata is being transmitted.

It specifies compatibility standards and signal voltages.


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TCP/UDP Ports

Ports are used in TCP or UDP communications to name

the ends of logical connections that transfer data.

These are used to provide access to a host computer.

In TCP/IP networking, a

port is a mechanism that allows acomputer to simultaneously support multiplecommunication sessions with computers and programs onthe network.

A port directs the request to a particular service that can befound at that IP address.


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Network Services

BOOTPBOOTP (Bootstrap Protocol) is an Internet protocol thatenables a diskless workstation to discover its own IPaddress.

DHCP

The Dynamic Host Configuration Protocol (DHCP) providesInternet hosts with configuration parameters.


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NATNAT (Network Address Translation) is an Internet standard

that enables a local area network (LAN) to use one set ofIP addresses for internal traffic and a second set ofaddresses for external traffic.

ICSICS (Internet connection sharing) is a method used forconnecting multiple computers in a LAN to the Internetthrough a single connection and a single IP address.

DNS

The Domain Name Service (DNS) protocol searches for

resources using a database distributed among differentname servers.


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SNMP

The Internet community developed SNMP (Simple NetworkMessage Protocol) to allow diverse network objects toparticipate in global network management architecture.

WINS

WINS (Windows Internet Naming Service), a system, which

determines the IP address associated with a particularnetwork computer.


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IP Addressing Architecture

IP address is a logical address assigned to a specific node.

A unique IP address is required for each host and networkcomponent that communicates using TCP/IP.

An IP address uniquely identifies a node or host on an IPnetwork.

S b tti


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SubnettingThe process of partitioning a single TCP/IP network into anumber of separate networks called subnets.

Subnetting was introduced to overcome some of theproblems that parts of the Internet were beginning toexperience with the two-level addressing hierarchy:

Subnet MaskA subnet mask is a 32-bit number that is used to partitionIP addresses into a network ID and a host ID.

Subnet masks are represented as four-octet dotted-decimal numbers, just as IP addresses are, except that themost common values for an octet in a subnet mask are 0and 255.


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Default Gateway

To send a packet to a destination subnet a host on a

network consults its internal routing table to determinewhich router to forward the packet to in order to have itreach the destination subnet.

If the routing table does not contain any routing informationabout the destination subnet, the packet is forwarded to thedefault gateway.

The host assumes that the default gateway knows what to

do with any packets that the host itself does not know howto forward.


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Public Vs Private Networks

A home or a small office, which has a computer networkthat has Internet Connection Sharing (ICS) enabled, hastwo network connections one public and one private.

The public network connection is the connection to theInternet.

The private side of the network is the computers that are

connected together and communicate with each other.


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WAN Technologies

Switching Techniques

For transmission of data, voice and images beyond a localarea, communication is normally achieved by transmittingdata from source to destination through a network ofintermediate switching nodes.

Their purpose is to provide a switching facility that willmove the data from one node to another until the datareaches their destination.

The most common switching techniquesare:circuit switching, message switching and packet switching.


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Circuit Switching

Circuit switching is the dominant technology for voice as

well as data communication today.

Circuit switching implies that there is a dedicatedcommunication path between two end-stations.

Packet Switching

Instead of transmitting the complete data end-to-end, datais transmitted in short packets.

A typical upper limit on packet length is 1 kilobyte. Eachpacket contains a portion of the users data plus somecontrol information.


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ISDN

ISDN (Integrated Services Digital Network) is an

international communications standard for sending voice,video, and data over digital telephone lines or normaltelephone wires.

ISDN supports data transfer rates of 64 Kbps (64,000 bitsper second).

FDDI

FDDI (Fibre Distributed Data Interface) is a high-performance optic token ring LAN running at 100 Mbpsover distances up to 200 km with up to 1000 stationsconnected.


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ATM (Asynchronous Transfer Mode)

ATM is a high speed, broadband transmission data

communication technology based on packet switching.

It is used by telephone companies, long distance carriers,and campus-wide backbone networks to carry integrated

data, voice, and video information.

It can work with either permanent virtual circuits (PVCs) orswitched virtual circuits (SVCs), depending on your widearea network (WAN) traffic needs.

The two main benefits of ATM are its high transmissionspeeds and its flexible bandwidth-on-demand capability.


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Frame Relay

Frame relay is a packet switching protocol for connecting

devices on a Wide Area Network.

It is a recently introduced service to transfer bits at areasonable speed and low cost.

Sonet/SDH

SONET is a Fibre optic WAN technology used to delivervoice, data, and video.

SONET networks are often used by telecommunicationproviders to provide the underlying transport mechanismfor Asynchronous Transfer Mode (ATM), networking.


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T-Carrier

It is a series of digital communication services provided by

telephone companies for high-speed permanent voice anddata connections.

E-carrier

E-carrier services are generally available wherever theparallel T-carrier services are not.

E-carrier services can be used for wide area network

(WAN) connections, for high-speed Internet connections,for private videoconferencing services, and for public framerelay services.


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Optical Carrier (OC-x)

Optical Carrier (OC-x) is a set of signaling rates designedfor transmission over Synchronous Optical Network(SONET).

The term opticalcarrier indicates that SONET runs over

Fibre-optic cabling.

Remote access protocols and services

RAS allows users to gain access to files and print serviceson the LAN from a remote location.

RAS

RAS contd..


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Microsoft allows remote node remote access functionalityon both its Windows NT/2000 platform, which allowsremote users to connect to a Windows NT/2000basednetwork.

In a mixed environment of Windows NT and Windows 2000RAS and RRAS servers, there are some limitations on

these tools .

Point-to-Point Protocol (PPP)

Point-to-Point Protocol (PPP) is an industry standard data-link layer protocol for wide area network (WAN)transmission that was developed in the early 1990s.


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Point-to-Point Tunneling Protocol (PPTP)

Tunneling is a technology for sending frames from one

network to another.

It enables network traffic to be encapsulated and routedover an unsecured public network such as the Internet.

Point-to-Point Tunneling Protocol (PPTP) allows thecreation of virtual private networks (VPNs), which tunnelTCP/IP traffic through the Internet.

PPTP is an extension of PPP and is based on PPPnegotiation, authentication, and encryption schemes.


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Independent Computing Architecture (ICA)

Independent Computing Architecture (ICA) is a general-purpose presentation services protocol for MicrosoftWindows operating system platforms.

ICA allows the user interface of an application to run withminimal consumption of resources on a client device whilethe actual application logic executes on an ICA-enabledserver.


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Security Protocols

Internet Protocol Security (IPSec)

IPSec is a protocol for negotiating and controlling thesecurity of transmissions over a TCP/IP internetwork.

IPSec defines standards for data encryption and dataintegrity at the level of Internet Protocol (IP) datagrams andcan be used to encrypt transmission of data and ensurethat the data originated from the sender and was notmodified in transit.


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Layer 2 Tunneling Protocol (L2TP)

L2TP is an Internet Engineering Task Force (IETF)

standard tunneling protocol, which is used to encapsulatePoint-to-Point Protocol (PPP) frames for transmission overTCP/IP, X.25, frame relay, or Asynchronous Transfer Mode(ATM) networks.

L2TP supports several of the authentication optionssupported by PPP.

These include Password Authentication Protocol (PAP),

Challenge Handshake Authentication Protocol (CHAP), andMicrosoft Challenge Handshake Authentication Protocol(MS-CHAP).


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Secure Sockets Layer (SSL)

Secure Sockets Layer (SSL) is a handshaking protocol for

communication over the Internet that provides secureauthentication and data encryption.

Kerberos Version 5 Authentication Protocol

The Kerberos version 5 provides a means of verifying theidentities of principals on an open, potentially insecurenetwork.

It discusses how the RFC standard Kerberos version 5authentication protocol is used in Windows Server 2003.


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Domain.msc: Active Directory Domains and Trusts

Dsa.msc: Active Directory Users and Computers

Eventvwr.msc: Event Viewer

Kerbtray.exe: Kerberos Tray

Klist.exe: Kerberos List

Ksetup.exe: Kerberos Setup

Kerberos Authentication Tools and Settings

Kerberos Authentication Tools and Settings contd..


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Ktpass.exe: Kerberos Keytab Setup

Netdom.exe: Windows Domain Manager

Netmon.exe: Network Monitor

Setspn.exe: Manipulate Service Principal Names forAccounts

2. protocols and standards

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