2. What do you study in this course?
This course will cover the following modules
TRANSPORT
LAYER
APPLICATION
LAYER
FUNDAMENTALS OF
NETWORKS
➢ Over view of
communication
➢ Network basics and
types
➢ Network Layering
➢ OSI Model
➢ Data and Signals
➢ Data Link Layer and
Its Functions
MEDIA ACCESS &
INTERNETWORKING
➢ Overview of media
access control
➢ Ethernet Standard
➢ Wireless LANS
➢ Bluetooth LE
➢ WiFi
➢ Zigbee
➢ IPv4
➢ Network Layer
Protocols
ROUTING
➢ Unicast and multicast
routing
➢ Algorithms and
Protocols
➢ Intra Domain and
Inter Domain
Protocols
➢ Overview of IPv6
➢ Transition from IPv4
to IPv6
➢ Overview of
Transport Layer
Protocols
➢ TCP and UDP
➢ Flow control
➢ Error Control
➢ Congestion Control
➢ Congestion Avoidance
➢ QoS
➢ Client Server
Programming
➢ WWW
➢ HTTP
➢ DNS
➢ E mail
➢ Peer to Peer
Networks
➢ Security Aspects
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3. Brief Recap of Data Link Layer in Module 1
The MAC layer is responsible for
moving data packets to and from
one Network Interface Card (NIC)
to another across a shared channel.
The LLC sublayer acts as an
interface between the media access
control (MAC) sublayer and the
network layer.
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4. Data Link Layer Functions:
•Media Access Control:
• Physical Addressing (MAC Address)
• Framing
•Logical Link Control:
• Flow Control – Controlling the Flow of Packets in the
network
• Error Control – Controlling the occurrence of Errors
during Transmission
• Access Control – Controlling the Nodes accessing the
Channel
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5. Overview of Module - 2
• Framing
• What is Framing
• Types of Framing
• Methods for identifying the
boundaries
• Flow Control
• What is flow control
• Types of flow control
• Access Control
• What is access control
• Types of access control
• Ethernet – IEEE 802.3
• Evolution of Ethernet
• Frame Format of Ethernet
• Access Control for Ethernet
• Performance Evaluation of Ethernet
• WLAN – IEEE 802.11
• Architecture
• Bluetooth
• WIFI
• Zigbee
• 6LowPan
• Network Layer Services
• IPv4
• Packet switching
• Network Layer Protocols
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6. Framing - Understanding
Hi Ganesh,
Hope this post finds you
in good health and
prosper. I am coming to
your home next week.
Please make all the
necessary arrangements
To:
Mr.Ganesh
8/20, SBI Colony
Salem - 636001
Mr.Jai, Avadi Chennai, 600109
DATA
SOURCE
DESTINATION
STAMPVALUE
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8. Frame Format of Ethernet for Example
Frame Format of WLAN for Example
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9. Types of Framing:
•There are 2 types of framing
➢Fixed length framing.
➢Variable length framing.
Header
(10bits)
Data
(20 bits)
Trailer
(10bits)
Header
(10bits)
Data
(variable)
Trailer
(10bits)
If I have 100 bits of data to transmit?
How many frames will be transmitted in FIXED LENGTH Framing? →
How many frames will be transmitted in VARIABLE LENGTH Framing? →
In case of variable length framing, How to identify the boundaries of the frame?
10. Identifying the Boundaries of the Frame
•Byte Oriented Framing
•Bit Oriented Framing
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11. Byte Oriented Framing
• Normally the frame from the upper layer comes with the header and
trailer information .
• Header contains source and destination address
• Trailer contains error detection and correction information
• In order to identify the frame boundaries an 8 bit flag is added at
both the ends
• These flag may contain protocol dependent special characters.
12. Problems with Flags
• This method is generally suited for text transmission, but in case
of audio and video transmission any flag value can be a part of
the data.
• If the pattern is as same as the flag, then the receiver may
misinterpret that it is the end of the frame
• This problem can be addressed by BYTE Stuffing.
• In this method an extra byte is added to the data section if the
pattern is as same as the flag. These bytes are usually referred to
as Escape Characters (ESC)
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14. Bit Oriented Framing
• In this type of framing flag uses an constant 8 bit sequence
“01111110” as the delimiter to indicate the boundaries of the frames.
• These flags may also create the same problem as Byte oriented
protocols.
• To overcome this problem we stuff 1 bit to the data to prevent the
pattern from looking as same as flag.
• This strategy is called as BIT Stuffing.
16. Session Summary
• What is Framing ?
• It is the process of adding Redundant information (Header and Trailer) to
the data units received from upper layer.
• Types of Framing ?
• Fixed Length Framing [Easy to process, Not Suitable for Larger Data]
• Variable Length Framing [ Best for Larger data, Difficult to identify the
Boundaries]
• Identifying the Boundaries of the Frame?
• Byte Stuffing [Flag is Added, Possibility of occurrence of Flag in Data,
Introduced ESC ]
• Bit Stuffing [Flags are kept constant, 1 bit is stuffed if 5 consecutive 1’s are
encountered]
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17. References:
• Behrouz A. Forouzan, ―Data communication and Networking, Fifth
Edition, Tata McGraw – Hill, 2013
• Larry L. Peterson, Bruce S. Davie, ―Computer Networks: A Systems
Approach, Fifth Edition, Morgan Kaufmann Publishers, 2011.
• Few online References (Will be Mentioned in the description Section)
Thank You…
