Seminar Presentation on Communication & Networking

1. A N A N D S R I V A S T A V A
Communication Network

2. What is Communication ?
 Communication activity of exchanging
information across space and time using various
methods.
 Communications is the physical transfer of data
a digital bit stream or a digitized analog signal
over a point-to-point or point-to-
multipoint communication channel.

3. Why It Is Needed ?
 Every day, in our work and in our leisure time, we
come in contact with and use a variety of modern
communication systems.
 Through these systems we are able to communicate
instantaneously with people on different continents,
transact our daily business, and receive information
about various developments and events of note that
occur all around the world.

4. How It Started ?
 Most of these modern-day communication systems
were invented and developed during the past
century.
 One of the earliest inventions of communications
was the invention of the electric battery by
Alessandro Volta in 1799.
 This invention made it possible for Samuel Morse
to develop the electric telegraph in 1837.

5. Continued…
 Electrical communications that was developed by
Morse, namely telegraphy, was a binary digital
communication system in which the letters of the
English alphabet were efficiently encoded into
corresponding variable-length code.
 Nearly forty years later, in 1875, Émile Baudot
developed a code for telegraphy in which each letter
was encoded into fixed-length binary code words of
length 5.

6. Continued…
 Alexander Graham Bell patented his invention of the
telephone in 1876.
 Significant advances in the quality and range of
service during the first two decades of the 20th
century allowed the telephone signal transmission
over great distances.
 During the past thirty years there have been
numerous significant advances in telephone
communications.

7. Communication Through The Ages
 Communication in Ancient
 Human Voice
 Writing
 Communication 1500-1800
 Printed Material
 Postal Service
 Communication in the 19th Century
 Telegraph
 Fax
 Telephone

8. Communication Through The Ages
 Communication in The 20th Century
 Radio
 Satellites
 Television
 Cell Phone
 Communication in The 21st Century
 Internet
 Wireless

9. The Basic Communication Classification
The Wired Communication
The Wireless Communication

10. The wired Communication

11. Why Wired ?
 The equipment is inexpensive.
 Many computers have a wired network adapter.
 Wired networks transfer information more swiftly
 Wired networks are generally more secure than
wireless networks

12. Wired Network
Consider Cable Television Service

13. Wired Network Protocols
Sender - Initiated Protocols
Receiver - Initiated protocols

14. Sender - Initiated Protocols
 Sender-initiated protocols have been characterized
as placing the responsibility of reliable delivery at the
sender.
 A sender-initiated protocol is one that requires the
source to receive ACK from the receiver before it is
allowed to release memory for the data associated
with the ACK.
 The source is required to know the receiver set, and
that the scheme suffers from the ACK implosion
problem.

15. Sender - Initiated Protocols

16. Limitation
 Error recovery is selective repeat, only packets that
are suspected to be lost or corrupted are
retransmitted,
 Limitation in processing the ACK of receiver set.
 The known methods that address this limitation is
using NAKS instead of ACK.

17. Receiver - Initiated protocols
 Receiver-initiated protocols are characterized as
placing the responsibility for ensuring reliable packet
delivery at each receiver.
 The critical aspect of these protocols is that no ACK
are used. The receivers send NAK back to the source
when a retransmission is needed, detected by either
an error, a skip in the sequence numbers used, or a
timeout.
 The source is unable to ascertain when it can safely
release data from memory.

18. Receiver - Initiated protocols

19. Limitation
 Receivers communicate NAK back to the source,
receiver-initiated protocols have the possibility of
experiencing NAK implosion problem at the source.
 The source is unable to ascertain when it can safely
release data from memory as NAK is send back only
on errors.
 Receiver-initiated with NAK avoidance (RINA)
protocols would be helpful to overcome this
limitation.

20. The Wireless Communication

21. Why Wireless ?
 To span a distance beyond the capabilities of typical
cabling.
 To provide a backup communications link in case of
normal network failure.
 To link portable or temporary workstations.
 To overcome situations where normal cabling is
difficult or financially impractical.
 To remotely connect mobile users or networks.

22. Wireless Network Communication
Consider Satellite Television Service.

23. Wireless Network Protocols
LEACH (Low Energy Adaptive Clustering
Hierarchy)
SPIN

24. LEACH
 LEACH(Low Energy Adaptive Clustering
Hierarchy)
 LEACH is a protocol in which most nodes transmit
to cluster heads, and the cluster heads aggregate and
compress the data and forward it to the base station.
 Each node uses a stochastic algorithm at each round
to determine whether it will become a cluster head in
this round.
 LEACH assumes that each node has a radio powerful
enough to directly reach the base station.

25. LEACH

26. LEACH (Advantages & Disadvantages)
 It utilizes TDMA making is more power efficient.
 Cluster Heads are chosen ones any node can be
chosen as cluster head based on rounds.
 Cluster Head is the one which compress and packs
the data and forwards it to the Base Station.
 LEACH assumes that each node has a radio powerful
enough to directly reach the base station or the
nearest cluster head, but that using this radio at full
strength all the time would waste energy.

27. SPIN
 SPIN is a family of adaptive protocols that use data
negotiation and resource-adaptive algorithms.
 SPIN is a data centric routing protocol assuming all
nodes in the network are base stations & nodes in
close proximity have similar data.
 All nodes can be assumed as base stations all
information is broadcasted to each node in the
network.
 User can query to any node and can get the
information immediately.

28. SPIN

29. SPIN (Advantages & Disadvantages)
 Before transmission, meta-data are exchanged
among sensors nodes (meta-data negotiation) via a
data advertisement procedure avoiding transmission
of redundant data.
 After receiving the data each node advertises it to its
neighbors and interested neighbors get this data by
sending a request message.
 SPINs data advertisement mechanism cannot
guarantee the delivery of data.

30. Questions ???