Network Models

Lesson Objectives - the students should be able to:

• Could explain the importance of Layered Task
• Clearly define the Sender, Receiver and Carrier
• Could discuss the Layered Architecture
• Could discuss the Peer-to-peer process
• Explain each responsibilities of the OSI Layer
• Understand the TCP/IP Protocol suite
• Enumerates and discuss responsibilities of each Layer of TCP/IP Protocol
• Could enumerate some protocols used in each Layer
• Understand the different Addressing and could differentiate on from the other.

Lecture on Network Models PPT

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• Data Communications Course Outline

Definition of Terms

• The International Standards Organization created a model called the Open Systems Interconnection, which allows diverse systems to communicate.
• The seven-layer OSI model provides guidelines for the development of universally compatible networking protocols.
• ISO is the organization. OSI is the model.
• The physical layer coordinates the functions required to transmit a bit stream over a physical medium.
• The data link layer is responsible for delivering data units from one station to the next without errors.
• The network layer is responsible for the source-to-destination delivery of a packet across multiple network links.
• The transport layer is responsible for the process-to-process delivery of the entire message.
• The session layer establishes, maintains, and synchronizes the interactions between communicating devices.
• The presentation layer ensures interoperability between communicating devices through transformation of data into a mutually agreed upon format.
• TCP/IP is a five-layer hierarchical protocol suite developed before the OSI model.
• The TCP/IP application layer is equivalent to the combined session, presentation,
  and application layers of the OSI model.
• The physical address, also known as the link address, is the address of a node as defined by its LAN or WAN.
• The IP address uniquely defines a host on the Internet.
• The port address identifies a process on a host.
• A specific address is a user-friendly address. 
• The physical addresses will change from hop to hop but the logical addresses usually remain the same.
• The physical addresses change from hop to hop but the logical and port addresses usually remain the same.
• Peer-to-peer processes are processes on two or more devices communicating at a same layer
• Headers and trailers are control data added at the beginning and the end of each data unit at each layer of the sender and removed at the corresponding layers of the receiver. They provide source and destination addresses, synchronization points, information for error detection, etc.

The Seven Layer of the OSI Model

• Application - responsible for providing services to the user.
• Presentation - responsible for translation, compression, and encryption.
• Session - responsible for dialog control and synchronization.
• Transport - responsible for the delivery of a message from one process to another.
• Network - responsible for the delivery of individual packets from the source host to the destination host.
• Data link - responsible for moving frames from one hop (node) to the next.
• Physical - responsible for movements of individual bits from one hop (node) to the next.

Summary of layers and functions

TCP/IP and OSI model

The Internet Model (TCP/IP protocol suite)

• Application
• Transport
• Network
• Data link
• Physical

The Network Support Layers

• Physical
• Data link
• Network

The User Support Layers

• session
• presentation
• application

Link the Network Support and User Support Layers

• Transport layer

Four levels of addresses the TCP/IP protocols

• Physical Addresses
• Logical Addresses
• Port Addresses
• Specific Addresses

Relationship of layers and addresses in TCP/IP

Protocols in the Network Layer of TCP/IP

• Internetworking Protocol (IP) - the transmission mechanism used by the TCP/IP
  protocols.
• Address Resolution Protocol (ARP) - used to associate a logical address with a
  physical address.
• Reverse Address Resolution Protocol (RARP) - allows a host to discover its Internet
  address when it knows only its physical address.
• Internet Control Message Protocol (ICMP) - mechanism used by hosts and
  gateways to send notification of datagram problems back to the sender. ICMP sends
  query and error reporting messages.
• Internet Group Message Protocol (IGMP) - facilitate the simultaneous
  transmission of a message to a group of recipients.

Note: You can proceed to take the multiple choice exam regarding this topic. Network Models - Set 1 MCQs

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credit: Behrouz A. Forouzan©2013 www.FroydWess.com

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