CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 1/30 Protocols and Standards Protocols and Standards Protocols Standards Standards Organizations

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 2/30 Protocols Definition and Need for Protocol Elements of protocols Syntax Semantics Timing

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 3/30 Standards Standards and standards Marking organization Categories of Standards De factor - meaning by fact or by conversion De jure - meaning by law or organization Standards Organizations Standards creation committees (ISO, ITU-T, ANSI,IEEE & EIA) Forums Regulatory agencies (TRCA)

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 4/30 Standards De jure (by law) De factor (by fact) Proprietary Non- Proprietary

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 5/30 Network Models

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 6/30 Communication Model/Network Model Model: -a frame or reference or set of guidelines on which communicating devices can understand each other. Network Model: Open Systems Interconnection – OSI Model Internet Model

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 7/30 OSI model

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 8/30 OSI is used as the theoretical model for how communication between devices, such as computer takes place. It define the way in which device interact There are seven layers in the OSI model: application, Presentation, Session, Transport, Network, Data Link and Physical. These layers make up a framework that defines the way in which physical hardware, media and software work together to communicate. Each layer of the OSI model is independent from every other in its purpose and responsibilities. Each must do its own job, as well as provide services to the layers above and below it. The model creates framework to understand how network communication is taking place, as well as aid in troubleshooting problems that arise within a network. The OSI model provides a structure for software programmers and Equipment manufacturers to develop product that will work together [interoperability] OSI Model

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 9/30 These services can be divided into horizontal and vertical communication models. The communication between layers in the same device is an example of vertical communication model. In the horizontal model, communication is between the same layer on different devices. This horizontal model is based on protocols that works at specific layers of the model. The top five layers of the OSI model are represented in software, while the lower layers are based on hardware. OSI Model

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 10/30 Sending a letter

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 11/30 Application layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 12/30 Presentation layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 13/30 Session layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 14/30 Transport layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 15/30 Network layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 16/30 Data link layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 17/30 Physical layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 18/30 Summary of layer functions

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 19/30 Internet Model Internet model is made up of five [5] layers

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 20/30 An exchange using the Internet model

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 21/30 Physical layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 22/30 Physical layer Physical layer is responsible for actual physical connection between devices.

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 23/30 The physical layer is responsible for transmitting individual bits from one node to the next. Note:

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 24/30 Data link layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 25/30 Data link Layer Data link layer has two sublayers and each provides its own services in the OSI model Data link Sublayers Logical Link Control [LLC] Media Access Control [MAC] LLC Sublayer: provides the interface between the media access method and the network layer protocol. MAC Sublayer: Is responsible for the connection to the physical media

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 26/30 The data link layer is responsible for transmitting frames from one node to the next. Note:

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 27/30 Node-to-node delivery

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 28/30 Example 1

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 29/30 Network layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 30/30 Network Layer This layer is responsible for the addressing and delivery of packet. Network address is a logical address based on numbering scheme that is independent of a devices hardware or location. Functions of the Network layer Add the network address to the packet Map the network to the device physical address Determine the best path for the packet Ensure that the packet is in the correct format for the destination network

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 31/30 The network layer is responsible for the delivery of packets from the original source to the final destination.

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 32/30 Source-to-destination delivery

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 33/30 Example 2

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 34/30 Transport layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 35/30 Transport Layer The function of the transport layer is to ensure that data packets it receives from the session layer arrive reliably. Two type of transmission Connection Oriented Connectionless Transport layer also has the job of managing the speed of communication between devices: flow control Features of Connection Oriented transmission Reliability Slower communication Packets are resent if a packet is un recognized or is not received Features of connectionless transmission Little or no Reliability Faster transmission Packet are not retransmitted

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 36/30 The transport layer is responsible for delivery of a message from one process to another. Note:

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 37/30 Reliable process-to-process delivery of a message

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 38/30 Example 3

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 39/30 Application layer

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 40/30 Application layer is the service provider. It gives service to the user of the network. Application layer works with the applications you use to communicate over the network. Example: SMTP-simple mail transfer protocol to send , HTTP (HyperText Transfer Protocol) to access the web page while surfing the Internet, FTP (file transfer protocol) transfer protocol to download a file from an FTP server. Application Services: File services Electronic-mail services Network printing services Application services Database services

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 41/30 The application layer is responsible for providing services to the user. Note:

CIT-Dept-IFM 2006/7 Institute of Finance Management 2006 CIT232- Computer Networks 42/30 Summary of duties