Internet standards are specifications created by the IETF and published as RFCs to define Internet technologies and methodologies. RFCs are approved by the IESG and assigned a unique integer identifier. The TCP/IP protocol suite is a set of communication protocols used to enable transmission of data over a network. It includes protocols like TCP, IP, UDP, and others. These protocols operate at different layers, with layers like link, internet, transport, and application. Communication between hosts uses the TCP/IP protocols through these layers.

1. Internet Standards:
• It is a specification of technologies and methodologies related to the
Internet.
• Internet Engineering Task Force (IETF):
– Internet Standards are created and published by a body.
• Request For Comment (RFC):
– It is basically an Internet Standards or set of RFCs.
– An RFC, after going through several revisions, is accepted by an RFC editor.
• Internet Engineering Steering Group (IESG):
– It approves each RFC is identified by a unique integer.
– They can be found at http://www.ietf.org/rfc.html
– It helpful for all Internet Users.
• Example:
– Specifications for HTTP/1.0 and HTTP/1.1 can be found in RFC 1945 and 2616
respectively.

2. TCP/IP Protocol Suite:
• It is a set of protocols used in the Internet and
other communication networks.
• It creates the technical foundation of the
Internet.
• Two primary protocols:
• Transmission Control Protocol (TCP)
• Internet Protocol (IP)
• But it consists of many other protocols.

4. • Each of which deals with a set of issues that arise while
designing a communication network.
• According to RFC 1122, only four layers.
– Link layer
– Internet layer
– Transport layer
– Application layer
• Each layer provides a well-defined set of services to its
upper layer and uses services provided by its lower layer.

5. Communication between two
hosts using TCP/IP

7. Host-to-Host or Peer-to-Peer and N/W Interface or Link and Internet or Network

8. TCP/IP suite of protocols
Layer Protocols
Applicati
on
HTTP, SMTP, SSH, Telnet, SIP, Gopher, IMAP, SNIMP, Rlogin, POP3, DNS, SSL,
FTP
Transpor
t
TCP, UDP
Internet IP, ICMP, IGMP, OSPF, BGP, RIP,ARP, RARP
Link HDLC

9. Link Layer:
• This is the lower most layer in TCP/IP protocol suite.
• It deals with LAN (Local Area Network).
• It is responsible for transferring data from one machine
to another within the same local network.
• Primary Function:
– Framing
– Error Detection
– Error Correction
– Flow Control
– Error Control
– Medium Access Control

10. Internet Layer:
• It is to deliver packets from one network to
another.
• Routing:
• It determines a suitable route from the source
computer to the target and delivers packets
through this route.
• Purpose:
• It introduces an addressing mechanism called
IP addressing.

11. Transport Layer:
• It is end-to-end message transfer.
• Types of services to its upper layer:
– Connection-oriented:
• The segments of a message are delivered in order.
• The TCP in a TCP/IP protocol suite provides connection-
oriented service.
– Connection-less:
• No such guarantee is given.
• User Datagram Protocol provides connection-less
service.

12. • It also introduces port numbers to identify
processes that run in a computer.
• It should also implement the following
optional tasks:
– Segmentation
– Flow Control
– Error Control
– Congestion Control

13. Application Layer:
• This is the layer that users actually interact
with.
• It provides interfaces to users for network
communication.
• Example:
• It provides an interface using which users can
transfer files from one computer to another
computer

15. IP Addresses:
• What is an IP Address?
– An IP address is a 32 bit sequence of 1’s and 0’s.
– A way to identify a machines on a network.
– TCP/IP protocol suite assigns a unique address.
– IP version 4, an IP address is a 32 bit binary number.
Purpose
Identifying a
host/network interface
Location addressing

16. Dotted Decimal Notation:
• IP addresses using 4 decimal numbers, each
representing 8 bits.
• The range 0 to 255.
• It separate by three dots (.).
• Example:
• IP Address: 203.197.107.107
• Binary Form:
11001011.11000101.01101011.01101011
• Growth of internet, a new system IPv6 was
introduced uses 128 bit address.

17. Part of an IP Address:
– Network Part:
• It identifies the network part is same for all hosts
belonging to the same network
– Host Part:
• The number of bits in the host part determines the
number of possible hosts within the network uniquely.

18. Classes for IP Address:
Class
es
Starts with 1st
Octet in Binary
Range ID Reserved
Network Host
Class
A
0XXXXXXX 0 to 127 or 1 to
126
W (8) x, y, z
(24)
Governments
Class
B
10XXXXXX 128 to 191 w, x (16) y, z
(16)
Medium
Companies
Class
C
110XXXXX 192 to 223 w, x, y (24) Z (8) Small
Companies
Class
D
1110XXXX 224 to 239 Reserved
for
Multicast
- Multicasting
Class
E
1111XXXX 240 to 255 Reserved
for
Experiment
- Future Use
Class D and E are reserved for research purpose but aren’t
used.

22. Classless Inter-Domain Routing:
• It creating allocation for IP Address blocks and
new rules of routing protocol using IPv4
addresses was implemented.
• Introduced: Variable-length network ID
• Result: Moderate utilization of IP addresses
• A network consisting of consecutive IP addresses
is very often represented as X/Y.
• Subnet ID: where X is the first IP address in the
series
• Network ID: where Y is the number of bits in this
field.

23. Example:
• 203.197.107.96/28 having 28 bits in the network ID.
• It means host ID field has 4 (32-28) bits.
• So, possible IP addresses in this subnet is 16 (24).
• They are 203.197.107.96-203.197.107.111.
• Out of these 16 addresses, only 14 (16-2) can be
assigned to hosts.
• First - 203.197.107.96 and Second - 203.197.107.111.
• It is used as subnet’s IP address and broadcast IP
address.
IP Address:
The concept of classful IP address isn’t used in practice.
It is only used in the technical jargon in network
administrator’s.

24. IPv4 Private Addresses:
• What is IPv4?
• IPv4 (Internet Protocol Version 4)
used to identify devices on a
network through an addressing
system.
• It uses 32-bit address scheme
allowing for a total of 2^32
addresses (just over 4 million
addresses).
• It including computers, smartphones
and game consoles – connect to the
internet requires an address.

25. • Early Network Design:
• IP addresses assigned to particular computers or
network devices were intended to be unique for global
end-to-end communication.
• It is exhausted quickly.
• So, there was a tremendous demand to find a way out
from this IPv4 address exhaustion.
• It was released that IP addresses used by the computers
in private networks need not be unique.
• So, Computers are not connected to the Internet.
• Example:
• Factory machines that communicate only with each
other via TCP/IP, need not have unique addresses.

28. Network Range Number of addresses
10.0.0.08/ (1 class A
network)
10.0.0.0 -
10.255.255.255
16,777,216
172.16.0.0/12 (16 class B
network)
172.16.0.0 -
172.313.255.255
1,048,576
192.168.0.0/16 (256 class C
network)
192.168.0.0 -
192.168.255.255
65,536
• Three ranges of IPv4 addresses for private networks.
• One range for each class (A, B, C) were reserved in RFC 1918.
• Theses addresses are not routed on Internet and use need not be
coordinated with an IP address registry.
• Today, Private networks typically connect to the Internet through
Network Address Translation (NAT).

31. MIME (Multipurpose Internet Mail
Extension):• Simple Mail Transfer
Protocol:
– It is important and
frequently used
protocol in TCP/IP
protocol suite.
– It is used to deliver
electronic mails (E
mail).
– SMTP was designed
to transfer only text
messages.

32. MIME
MIME extends the format of
following of
email supports:
• Text in character sets other that
ASCII
• Non text attachments.
• Message bodies with multiple
parts.
• Header information in non ASCII
character sets.

33. Sending Large Message:
• When sending a large message, it splits them into small parts is called
multi part message.
• Peoples written emails can be transmitted through this SMTP in MIME
format.
• This format is specified as a part of HTTP/1.1.
• MIME has grown beyond and describing the content of email to describing
content type.
– content type = multipart /related
– content type = multipart/mixed
Example:
– In communication protocol like HTTP for WWW.
– HTTP requires data transmitted in context of email like messages but data
aren’t actually text.
Important:
– MIME use character encodings other than ASCII, and 8-bit binary content.
– Mapping message into and out of MIME format is typically done automatically
by e-mail or mail servers when sending or receiving e-mail to the internet.

34. Cyber Laws:
• Cyber Laws is a system of law and regulation for the cyber space.
• It refers to all the legal and regulatory aspects of the Internet and the
applicable to WWW.
Cyber Law-The Law of Internet & WWW:
 The number of users doubling using the Internet every 100 days
 New and sensitive issues related to various legal aspects of
cyberspace began cropping up.
 A new and highly specialized branch of law came into existence
Example:
Cyber crimes involves traditional criminal activities such as theft,
fraud, forgery, defamation and mischief. It can be categorized into two
types:

35. Categories of Cyber Crime:
Using computers as a
tool
Computers are used to attack other
computers.
It includes hacking, virus/worm attacks,
DOS attacks, denial of service attacks,
Trojan attacks, etc.
Using computers as a
weapon
Computers are used as a weapon.
It includes credit card frauds,
email spoofing, email spamming,
email bombing, cyber terrorism,
EFT frauds, etc.