CPE401_MODULE2B_Data_Communication_and_Networking.pdf

Data communication and Network Slides(Professor Oluwaranti)

1. CPE401
Data Communications & Computer
Networks
Prof. A. I. Oluwaranti
[email protected]
Slides developed from Data Communications and Networking. Forth Edition. By Behrouz A. Forouzan and other online materials
Module 2b:

2. •Responsible of:
•Moving frames from one hop (node) to
the next.
•Framing: divided the stream of bits
received from the network layer
manageable data units called frames.
•Physical address (MAC address).
•Flow control.
•Error control: added trailer to the end of
frame.
•Access control.
•Hop to hop delivery
Layer 2: Data Link layer

3. a)Error control to compensate for the
imperfections of the physical layer.
b)Flow control to keep a fast sender from
swamping a slow receiver.
•Main topics:
•Framing methods
•Error detection and correction
methods
•Flow control
•Frame format
•IEEE LAN standards
•Bridges
•Switches (multi-port bridges)
Data Link layer contd.

4. Data Link layer contd.
101101101010110001001110110000001

5. Hop-to-Hop delivery

6. •The network layer is responsible:
•The delivery of individual packets from the original source to the final destination
•Logical addressing: if the packet passes the network boundary there is a need for another addressing system to help (source to destination) connection.
•Routing: route or switch the packet to final destination.
•Source-to-destination delivery (End-to-End).
Layer 3: Network Layer

7. a)Controls the operation of the
subnet.
b)Routing packets from source to
destination.
c)Logical addressing.
•Main topics:
•Internetworking
•Routing algorithms
•Internet Protocol (IP) addressing
•Routers
Network Layer contd.

8. Network Layer contd.

9. Source-to-Destination delivery

10. •The transport layer is responsible for:
•Service point or Port addressing
•Segmentation and reassembly:
§a message is divided into
transmittable segments each
segment containing a sequence no.
•Connection Control: connection
oriented or connectionless.
•Flow control
•Error control
Layer 4: Transport Layer

11. a)Provides additional Quality of Service.
b)Heart of the OSI model.
•Main topics:
•Connection-oriented and
connectionless services
•Transmission Control Protocol (TCP)
•User Datagram Protocol (UDP)
Layer 4: Transport Layer contd.

12. Transport Layer contd.

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

14. •Dialogue control: design to
establish, maintain, and
synchronize the interaction
between communicating systems.
•Synchronization: it allows a
process to add checkpoints or
synchronization points to a data
stream.
Layer 5: Session Layer

15. Session Layer contd.

16. •Design to the handle the syntax
and semantic of the information
exchanged between 2 systems.
•Design for:
•data translation
•encryption
•decryption
•compression.
•Where is data compression required?
Layer 6 :Presentation Layer

17. Presentation Layer (contd)

18. Layer 7:
Application
Layer
The application layer is responsible for
providing services to the user.
Mail services
File transfer, access and management
Remote log-in or network virtual terminal
Accessing the World Wide Web
Directory service

19. a)Provides protocols that are commonly needed.
•Main topics:
•File Transfer Protocol (FTP)
•HyperTextTransfer Protocol (HTTP)
•Simple Mail Transfer Protocol (SMTP)
•Simple Network Management Protocol (SNMP)
•Network File System (NFS)
•Telnet
Application Layer (contd)

20. Application Layer contd.
HTTPTelnetSMTPHTTPTelnetSMTP

21. data
datadatadata
Network header data
Frame HNetwork Hdata
Segments
packets
Frames
Bits
From trailer
data stream
data stream
data stream
Application
Presentation
Session
Transport
Network
Data link
Physical 1110111 0111 011111101

22. Summary

23. •The TCP/IP protocol suiteis a
hierarchical protocol , made
of five layers:
•Application layer
•Transport layer
•Network layer
•Data link layer
•Physical layer
TCP/IP Protocol Suite

24. •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, and 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, and application.
TCP/IP PROTOCOL SUITE

25. TCP/IP and OSI model

26. •Fourlevelsofaddresses
areusedinaninternet
employingtheTCP/IP
protocols:
•physicaladdress
•logicaladdress
•portaddress
•specificaddress
ADDRESSING

27. Relationship of layers and addresses in TCP/IP
SCTP: Stream Control Transmission Protocol
TCP: Transmission Control Protocol
UDP: User Datagram Protocol

28. •Physical address, also known as the link address, is the address of a node as defined by its LAN or WAN.
•It is included in the frame used by the data link layer. It is the lowest-level address
•The size and format of these addresses vary depending on the network. E.g., Ethernet uses a 6-byte (48-bit) physical address that is imprinted on the NIC
Physical Address

29. •In Figure below, a node with physical address 10 sends a frame to a node with
physical address 87. The two nodes are connected by a link (bus topology LAN). As the figure shows, the computer with physical address 10 is the sender, and the
computer with physical address 87 is the receiver.
Example 1

30. •Figure 2 shows a part of an internet with two routers connecting three
LANs. Each device (computer or router) has a pair of addresses (logical
and physical) for each connection.
•In this case, each computer is connected to only one link and
therefore has only one pair of addresses. Each router, however, is
connected to three networks (only two are shown in the figure).
•So each router has three pairs of addresses, one for each connection.
Example 2

31. Figure 2. IP addresses

32. •Figure 3 shows two computers communicating via the Internet.
•The sending computer is running three processes at this time with port
addresses a, b, and c.
•The receiving computer is running two processes at this time with port
addresses jand k.
•Process ain the sending computer needs to communicate with
process jin the receiving computer.
•Note that although physical addresses change from hop to hop, logical
and port addresses remain the same from the source to destination.
Example 3

33. Figure 3 Port addresses

34. OSI and Protocol Stack
OSI ModelTCP/IP HierarchyProtocols
7th
Application Layer
6th
Presentation Layer
5th
Session Layer
4th
Transport Layer
3rd
Network Layer
2nd
Link Layer
1st
Physical Layer
Application Layer
Transport Layer
Network Layer
Link Layer
Link Layer : includes device driver and network interface card
Network Layer : handles the movement of packets, i.e. Routing
Transport Layer : provides a reliable flow of data between two hosts
Application Layer : handles the details of the particular application

35. Packet Encapsulation
n The data is sent down the protocol stack
n Each layer adds to the data by prepending headers
22Bytes20Bytes20Bytes4Bytes
64 to 1500 Bytes