1. Lecture
Protocol & Model
Ashis Talukder, MIS, EWU.

2. Last Class
Ashis Talukder, MIS, EWU.

3. Network Topology Definition Classification: BUS TREE STAR RING MESH
HYBRID
Ashis Talukder, MIS, EWU.

4. Today’s Class
Ashis Talukder, MIS, EWU.

5. Protocol & Protocol Models
Introduction: Protocol
OSI Model
TCP/IP Model
Ashis Talukder, MIS, EWU.

6. Protocol
Protocol is defined as a set of rules that governs the exchange of data between two entities.
Key elements of a protocol:
Syntax: data format
Semantics: control info & error handling
Timing: speed matching & sequencing
Ashis Talukder, MIS, EWU.

7. Protocol Models Open System Interface (OSI) Model
Transmission Control Protocol/Internet Protocol (TCP/IP) Model
Ashis Talukder, MIS, EWU.

8. OSI model
To address the problem of network incompatibility, the International Organization for Standardization (ISO) researched networking models like
Digital Equipment Corporation net (DECnet),
Systems Network Architecture (SNA), and
TCP/IP
Proposed a generally applicable set of rules for all networks.
Using this research, the ISO created a network model that helps vendors create networks that are compatible with other networks.
Ashis Talukder, MIS, EWU.

9. OSI model
The Open System Interconnection (OSI) reference model released in 1984 was the descriptive network model that the ISO created.
It provided vendors with a set of standards that ensured greater compatibility and interoperability among various network technologies produced by companies around the world.
Ashis Talukder, MIS, EWU.

10. OSI Reference Model
has become the primary model for network communications.
Although there are other models in existence, most network vendors relate their products to the OSI reference model.
This is especially true when they want to educate users on the use of their products.
It is considered the best tool available for teaching people about sending and receiving data on a network.
It provided vendors with a set of standards that ensured greater compatibility and interoperability among various network technologies produced by companies around the world.
Ashis Talukder, MIS, EWU.

11. Layers of OSI model Physical Layer Data Link layer Network Layer
Transport Layer
Session layer
Presentation layer
Application layer
Ashis Talukder, MIS, EWU.

12. Benefits of OSI Models
Ashis Talukder, MIS, EWU.

13. Physical Layer encoding/decoding of signals
preamble generation/removal
bit transmission/ reception
transmission medium and topology
Ashis Talukder, MIS, EWU.

14. Physical Layer Four Specifications: Devices: Electrical Mechanical
Functional
Procedural
Devices:
Repeater
NIC
Hub
Ashis Talukder, MIS, EWU.

15. Data Link Layer Logical Link Control interface to higher levels
flow and error control
Media Access Control
on transmit assemble data into frame
on receive disassemble frame
govern access to transmission medium
for same LLC, may have several MAC options
Ashis Talukder, MIS, EWU.

16. Data Link Layer where central distributed how synchronous asynchronous
greater control, single point of failure
distributed
more complex, but more redundant
how
synchronous
capacity dedicated to connection, not optimal
asynchronous
in response to demand
Ashis Talukder, MIS, EWU.

17. Data Link Layer
Devices
Bridge
Switch
Ashis Talukder, MIS, EWU.

18. Data Link Layer round robin each station given turn to transmit data
reservation
divide medium into slots
good for stream traffic
contention
all stations contend for time
good for bursty traffic
simple to implement
tends to collapse under heavy load
Ashis Talukder, MIS, EWU.

19. Network Layer
Ashis Talukder, MIS, EWU.

20. Network Layer Non reliable Best Effort delivery
Provide logical addressing (IP address)
No error correction
Host-to-host Connectivity
Routing
Selecting the best path
Forward the packet through that path
Device: Router
Ashis Talukder, MIS, EWU.

21. Transport Layer encapsulation Segmentation and reassembly
connection control
Establish
Maintain
terminate
ordered delivery
flow control
error control
Detection
recovery
Ashis Talukder, MIS, EWU.

22. Transport Layer Addressing Reliable transmission
Port Address
Handle Multiple Conversation
Reliable transmission
Sends acknowledgements
Also provide connectionless stream data transmission (UDP)
Ashis Talukder, MIS, EWU.

23. Session Layer Dialogue Discipline Simplex Half Duplex Full Duplex
Establish, manage & maintain session between applications
Ashis Talukder, MIS, EWU.

24. Presentation Layer Compress/Decompress Data Structure
Ensure readable/usable format
Data format
Ashis Talukder, MIS, EWU.

25. Application Layer provide support for user applications
Ashis Talukder, MIS, EWU.

26. TCP/IP Model
Ashis Talukder, MIS, EWU.

27. TCP/IP Protocol Model
The U.S. Department of Defense (DoD) created the TCP/IP reference model because it wanted a network that could survive any conditions.
Some of the layers in the TCP/IP model have the same name as layers in the OSI model.
Ashis Talukder, MIS, EWU.

28. Network Access Layer
The network access layer is concerned with all of the issues that an IP packet requires to actually make a physical link to the network media.
It includes the LAN and WAN technology details, and all the details contained in the OSI physical and data link layers.
Ashis Talukder, MIS, EWU.

29. Internet Layer The purpose of the Internet layer is
to send packets from a network node and
to have them arrive at the destination node independent of the path taken.
Ashis Talukder, MIS, EWU.

30. Transport Layer Segmenting upper-layer application data
Establishing end-to-end operations
Sending segments from one end host to another end host
Ensuring data reliability
Providing flow control
Ashis Talukder, MIS, EWU.

31. Application Layer
Handles high-level protocols, issues of representation, encoding, and dialog control.
The TCP/IP protocol suite combines all application related issues into one layer and ensures this data is properly packaged before passing it on to the next layer.
Ashis Talukder, MIS, EWU.

32. Peer-to-peer Communication
Ashis Talukder, MIS, EWU.

33. Peer-to-peer Communication
Ashis Talukder, MIS, EWU.

34. Comparison of OSI & TCP/IP model
Similarities include:
Both have layers.
Both have application layers, though they include very different services.
Both have comparable transport and network layers.
Both models need to be known by networking professionals.
Both assume packets are switched. This means that individual packets may take different paths to reach the same destination. This is contrasted with circuit-switched networks where all the packets take the same path.
Ashis Talukder, MIS, EWU.

35. Comparison of OSI & TCP/IP model
Dissimilarities include:
TCP/IP combines the presentation and session layer issues into its application layer.
TCP/IP combines the OSI data link and physical layers into the network access layer.
TCP/IP appears simpler because it has fewer layers.
TCP/IP protocols are the standards around which the Internet developed, so the TCP/IP model gains credibility just because of its protocols. In contrast, networks are not usually built on the OSI protocol, even though the OSI model is used as a guide.
Ashis Talukder, MIS, EWU.

36. Advantage of Layered Approach
It breaks network communication into smaller, more manageable parts.
It standardizes network components to allow multiple vendor development and support.
It allows different types of network hardware and software to communicate with each other.
It prevents changes in one layer from affecting other layers.
It divides network communication into smaller parts to make learning it easier to understand.
Ashis Talukder, MIS, EWU.

37. …???
Ashis Talukder, MIS, EWU.

38. Next Class
Ashis Talukder, MIS, EWU.

39. Early Protocl Early Protocols: Ethernet: ALOHA Slotted ALOHA CSMA
CSMA/CD
Ethernet:
10 BASE
100BASE
1000BASE
Ashis Talukder, MIS, EWU.

40. Thank You…!!!
Ashis Talukder, MIS, EWU.