1. Introducing Network Standards
Open Systems Interconnection (OSI) Model
IEEE 802.x Standard
Device Drivers and OSI 1

2. Protocols and Standards
Standards Organizations

3. Protocols Definition and Need for Protocol Elements of protocols
Syntax
Semantics
Timing

4. 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)

5. Standards

6. Network Models

7. 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

8. OSI model

9. OSI Model
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]

10. OSI Model
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.

11. Sending a letter

12. Internet Model
Internet model is made up of five [5] layers

13. An exchange using the Internet model

14. Physical layer

15. Physical layer
Physical layer is responsible for actual physical connection between devices.

16. Note:
The physical layer is responsible for transmitting individual bits from one node to the next.

17. Data link layer

18. 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

19. Note:
The data link layer is responsible for transmitting frames from one node to the next.

20. Node-to-node delivery

21. Example 1
In this example a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link. At the data link level this frame contains physical addresses in the header. These are the only addresses needed. The rest of the header contains other information needed at this level. The trailer usually contains extra bits needed for error detection

22. Example 1

23. Network layer

24. 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

25. The network layer is responsible for the delivery of packets from the original source to the final destination.

26. Source-to-destination delivery

27. Example 2
If we want to send data from a node with network address A and physical address 10, located on one LAN, to a node with a network address P and physical address 95, located on another LAN. Because the two devices are located on different networks, we cannot use physical addresses only; the physical addresses only have local jurisdiction. What we need here are universal addresses that can pass through the LAN boundaries. The network (logical) addresses have this characteristic.

28. Example 2

29. Transport layer

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

31. Note:
The transport layer is responsible for delivery of a message from one process to another.

32. Reliable process-to-process delivery of a message

33. Example 3
shows an example of transport layer communication. Data coming from the upper layers have port addresses j and k (j is the address of the sending process, and k is the address of the receiving process). Since the data size is larger than the network layer can handle, the data are split into two packets, each packet retaining the port addresses (j and k). Then in the network layer, network addresses (A and P) are added to each packet.

34. Example 3

35. Application layer

36. Application layer is the service provider
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

37. Note:
The application layer is responsible for providing services to the user.

38. Figure 2.16 Summary of duties