This document provides an overview of computer networking fundamentals. It covers topics such as network types (LANs and WANs), common network architectures (client-server, peer-to-peer, mainframe), OSI and TCP/IP models, Ethernet technologies, and common network devices (hubs, switches, routers). Each layer of the OSI model is described along with its purpose and functions. Ethernet cabling types and speeds are also outlined. The document serves as an introductory guide to basic internetworking concepts.

1. Computer Networking
Fundamentals
By,
Uma

2. Module - 1
Basic
Internetworking

3. What is Networks?
 Networks - Link computers together to share files and
communicate and do all the things we like to do.
 Networks range in size from the smallest and simplest
network—two computers connected together—to the largest
and most complex network of all—the Internet.

4. Network Types - Local Area Network

5. Wide Area Network

6. Architecture of Networks
 Client/Server
 Peer to Peer
 Mainframe/Terminal

7. Servers and Clients

8. Peer-to-Peer Network

9. MainFrame/Terminal

10. ConnectionOriented Communication

11. Connectionless Communication

12. Module - 2
OSI Reference Model

13. OSI Layers

14. TCP/IP Model

15. Application Layer
 Purpose
 User application to network service interface
 Examples
 FTP
 E-mail services – POP3,SMTP
 HTTP
 Telnet

16. Functions of Application Layer
 Identifies communication partners
 Determines resource availability
 Synchronizes communication

17. Presentation Layer
 Purpose
 Formats data for exchange between points of
communication
 Example:
 Redirector software
 Formats for transmission to the server

18. Functions of Presentation Layer
 Protocol conversion
 Data translation
 Encryption
 Character set conversion
 Expansion of graphics command

19. Session Layer
 Purpose
 Oversee a communication session
Establish
Maintain
Terminate

20. Functions of Session Layer
 Performs name recognition and related security
 Synchronization between sender and receiver
 Assignment of time for transmission
 Start time
 End time etc.

21. Transport Layer
 Purpose
 Repackage proper and efficient delivery of
packages
Error free
In sequence
Without duplication

22. Functions of Transport Layer
 For sending data
 Repackage the message to fit into packets
Split long messages
Assemble small messages
 On receiving data
 Perform the reverse
 Send an acknowledgment to the sender
 Solve packet problems
 During transmission and reception

23. Network Layer
 Purpose
 Addressing and routing the packets
 Example application at the router
 If the packet size is large, splits into small
packets

24. Functions of Network Layer
 Address messages
 Address translation from logical to physical
 Ex: nganesa ----------> 102.13.345.25
 Routing of data
 Based on priority
 Best path at the time of transmission
 Congestion control

25. Data Link Layer
 Purpose
 Manages the flow of data over the physical
media
 Responsible for error-free transmission over the physical
media
 Assures error-free data submission to the Network Layer

26. Datalink Layer Functions
 Point of origin
 Packages data for transmission over physical line
 Receiving end
 Packages data for submission to the network layer
 Deals with network transmission protocols
 IEEE 802. protocols

27. Datalink Layer Subdivision
 Logical Link Control (LLC) sub-layer
 Manages service access points (logical link)
 Error and flow control
 Media Access Control (MAC) sub-layer
 Applies directly to network card
communication
 Access control

28. Physical Layer
 Purpose
 Deals with the transmission of 0s and 1s over
the physical media
Translation of bits into signals
 Example
 Pulse duration determination
 Transmission synchronization

29. Functions of Physical Layer
 Encode bits into signals
 Carry data from the h higher layers
 Define the interface to the card
 Electrical
 Mechanical
 Functional
 Example: Pin count on the connector

30. Module - 3
Ethernet
Technologies

31. Ethernet Cabling Types
 Coaxial cabling
Thinnet
Thicknet
 Twisted-pair cabling
Cat 3
Cat 5
Cat 5e
Cat 6
 Fiber optic cabling
Single mode and Multi mode

32. Ethernet - RJ45

33. Types of Ethernets
 10BaseT – runs at 10Mbps
 100BaseT – runs at 100Mbps – Fast Ethernet
 1000BaseT – runs at 1000Mbps or 1Gbps – Gigabit
Ethernet
 10000BaseT – runs at 10000Mbps or 10Gbps Ethernet

34. Module - 4
Hubs,Switches and
Routers

35. Network Device Icons

36. Layer 1 Hubs
 no intelligent forwarding whatsoever
 hubs will always forward every frame out every port
 operate at half-duplex, which allows a device to either
transmit or receive data, but not simultaneously
 Ethernet utilizes Carrier Sense Multiple Access with Collision
Detect (CSMA/CD) to control media access.

37. Layer 2 Switches
 Layer-2 devices build hardware address tables, which will
contain the following at a minimum:
 Hardware addresses for host devices
 The port each hardware address is associated
with
 intelligent forwarding decisions based on frame (Data-Link)
headers.
 Can operate in full duplex.