Chapter 2 Network Models Copyright © The McGraw-Hill Companies, Inc. Permission

Chapter 2 Network Models Copyright © The McGraw-Hill Companies, Inc. Permission www.phwiki.com

Chapter 2 Network Models Copyright © The McGraw-Hill Companies, Inc. Permission

Conrad, Rob, Morning Drive-Time Personality has reference to this Academic Journal, PHwiki organized this Journal Chapter 2 Network Models Copyright © The McGraw-Hill Companies, Inc. Permission required as long as reproduction or display. 2-1 LAYERED TASKS We use the concept of layers in our daily life. As an example, let us consider two friends who communicate through postal mail. The process of sending a letter to a friend would be complex if there were no services available from the post office. Sender, Receiver, in addition to Carrier Hierarchy Topics discussed in this section: Figure 2.1 Tasks involved in sending a letter

Courtauld Institute of Art, University of London GB www.phwiki.com

This Particular University is Related to this Particular Journal

2-2 THE OSI MODEL Established in 1947, the International St in addition to ards Organization (ISO) is a multinational body dedicated to worldwide agreement on international st in addition to ards. An ISO st in addition to ard that covers all aspects of network communications is the Open Systems Interconnection (OSI) model. It was first introduced in the late 1970s. Layered Architecture Peer-to-Peer Processes Encapsulation Topics discussed in this section: ISO is the organization. OSI is the model. Figure 2.2 Seven layers of the OSI model

Figure 2.3 The interaction between layers in the OSI model Figure 2.4 An exchange using the OSI model 2-3 LAYERS IN THE OSI MODEL In this section we briefly describe the functions of each layer in the OSI model. Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer Topics discussed in this section:

Figure 2.5 Physical layer The physical layer is responsible as long as movements of individual bits from one hop (node) to the next. Figure 2.6 Data link layer

The data link layer is responsible as long as moving frames from one hop (node) to the next. Figure 2.7 Hop-to-hop delivery Figure 2.8 Network layer

The network layer is responsible as long as the delivery of individual packets from the source host to the destination host. Figure 2.9 Source-to-destination delivery Figure 2.10 Transport layer

The transport layer is responsible as long as the delivery of a message from one process to another. Figure 2.11 Reliable process-to-process delivery of a message Figure 2.12 Session layer

The session layer is responsible as long as dialog control in addition to synchronization. Figure 2.13 Presentation layer The presentation layer is responsible as long as translation, compression, in addition to encryption.

Conrad, Rob WMJJ-FM Morning Drive-Time Personality www.phwiki.com

Figure 2.14 Application layer The application layer is responsible as long as providing services to the user. Figure 2.15 Summary of layers

2-4 TCP/IP PROTOCOL SUITE The layers in the TCP/IP protocol suite do not exactly match those in the OSI model. The original TCP/IP protocol suite was defined as having four layers: host-to-network, internet, transport, in addition to application. However, when TCP/IP is compared to OSI, we can say that the TCP/IP protocol suite is made of five layers: physical, data link, network, transport, in addition to application. Physical in addition to Data Link Layers Network Layer Transport Layer Application Layer Topics discussed in this section: Figure 2.16 TCP/IP in addition to OSI model 2-5 ADDRESSING Four levels of addresses are used in an internet employing the TCP/IP protocols: physical, logical, port, in addition to specific. Physical Addresses Logical Addresses Port Addresses Specific Addresses Topics discussed in this section:

The physical addresses will change from hop to hop, but the logical addresses usually remain the same. Example 2.5 A port address is a 16-bit address represented by one decimal number as shown. 753 A 16-bit port address represented as one single number.

Conrad, Rob Morning Drive-Time Personality

Conrad, Rob is from United States and they belong to WMJJ-FM and they are from  Birmingham, United States got related to this Particular Journal. and Conrad, Rob deal with the subjects like Entertainment; Music

Journal Ratings by Courtauld Institute of Art, University of London

This Particular Journal got reviewed and rated by Courtauld Institute of Art, University of London and short form of this particular Institution is GB and gave this Journal an Excellent Rating.