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1. Communication Using a Network

2. Data Communication
• Transmission of information between two computers
or nodes
Basic
Components
Sender Receiver Medium Message Protocol

3. Signaling Techniques – I
• Two types of Signaling techniques:
– Baseband
– Broadband
• Baseband Signals:
– Uses single frequency to transmit data
– Transmit information in digital form

4. Signaling Techniques – II
• Broadband Signals:
– Data is transmitted using more than one frequency
– Uses analog signals
– Adds additional information to carrier signals by process
of modulation

5. Network Interface Card (NIC) - I
• Hardware device used to connect different computers
on Network
• Serves as a link for sending and receiving data on a
network
• MAC address is address assigned by IEEE to identify
network card
NIC Types
Ethernet Card Token Ring Card

6. Network Interface Card (NIC) - II
• Operates at layer 2 of the OSI model
• Supports data transfer rate of 10, 100 or 1000
Mbps
• User can select an NIC depending on the type
of network, protocol and media used
• MAC address is stored on the PROM of the
NIC

7. Ethernet Card
• Used in devices which are connected using Ethernet
technology
• Two types of Ethernet network card – Wired and
wireless
• A wireless Ethernet card can not communicate with a
wired Ethernet card and vice-versa
• Different types of Ethernet cards can be used depending
on the type of network and corresponding connector
that is required

8. Types of Ethernet Card - I
• 10Base-5 (Thicknet) NIC
• 10Base-2

9. Types of Ethernet card - II
• 10BaseT
• Fiber –optic

10. Token Ring Card
• Used to connect to a token ring network
• Assigned a MAC address by IEEE
• Maximum of two token ring
cards can be installed at any
node
• Consists of 9 pin DIN
type connector which connects
card to network cable

11. Physical Connections
• Physical Connections
– NIC either connected on a PCI or PCI-X slot
– NIC cards can be connected to an USB port or can have a
PC card connection
• Depends on one of the cable connectors:
– BNC connector
– ST-fiber optic connector
– RJ-45 connector

12. Lights on NIC and hub
• Different LEDs on NIC:
– Link LED
– ACT LED
– Speed LED
– Collision LED
• LEDs on Hub:
– Power LED
– Port LED

13. Different LEDs on a NIC
• Link LED – Used to indicate whether any
network connection is present or not
• Act LED – If this LED flashes it indicates that
some activity is taking place on the network
• Speed LED – ON state indicates that it
operates at 100 Mbps and off for 10 Mbps
• Collision LED – Glows when a collision takes
place and present on some old NICs

14. MAC Address
• Also known as hardware or physical address
• Used to identify nodes at lower levels of the OSI model
• MAC address assigned by IEEE
• Is a 12 digit hexadecimal number (48 bit address)

15. Frame Structure
• A MAC frame is divided into 4 parts
• A maximum of 1500 bytes of data can be sent
in a frame
• CRC is only 4 bytes long

16. MAC vs IP address
MAC address IP address
Functions at data link Functions at network layer
layer
It is a physical address It is a logical address
It is fixed It changes with the
relocation of device from
one network to another
It is a 48 bit address It is a 32 bit address

17. Installing the NIC
• Different factors while choosing NIC:
– Bus type (Expansion slot)
– Speed
– Connection type (cabling)
• Hardware Requirements:
– Pentium I/233MHz
– 32 MB RAM
– 2 GB of available hard disk

18. Direct Cable Connection
• One device acts as a host and other acts as a guest
• Can also use infrared connection, if both nodes have required
hardware
• All the latest versions of windows provide a software which
allows a user to have a direct serial-to-serial, parallel-to-
parallel, or infrared-to-infrared connection with the other PC.
• To establish a connection using serial ports, a cable known as
null modem is used
• Connection speed of serial data cable connection is very slow
but it’s a cheaper option when NICs are not available

19. Diagnostic and Repair of Physical
Cabling using tools
• Tools can be used to identify the problems and also
troubleshoot these problems
• Various tools available for checking network are:
– Volt-ohm meters (VOMs) – Cable-testing tool used to
measure parameters
• Analog
• Digital

20. Tone generators and probe – I
• Tone generator is a network troubleshooting tool
• Consists of single or multi-tone signal, two test leads and
a 4-conductor modular cable
• Acts like a radio transmitter
• Probe:
– Works like a radio receiver
– Catches a tone when placed near
wire

21. Optical tester
• Fiber optic NICs mostly do not have any lights so making
the diagnosis of the problem becomes little difficult
• Optical tester is used to inspect the quality of the
connections