Internet Technology

1. Internet Protocol Overview
Unit 2
By
Deep Raj Bhujel

2. Internet Protocol Suite:
• The Internet protocol
suite is the set
of communications
protocols used for
the Internet and similar
networks, and generally
the most
popular protocol
stack for wide area
networks is commonly
known as TCP/IP

3. From lowest to highest, the layers are:
• The link layer (commonly Ethernet) contains
communication technologies for a local network.
• The internet layer (IP) connects local networks, thus
establishing internetworking.
• The transport layer (TCP) handles host-to-host
communication.
• The application layer (for example HTTP) contains all
protocols for specific data communications services on
a process-to-process level (for example how a web
browser communicates with a web server).

4. Application layer (process-to-
process):
• These services are end user-related: authentication,
data handling, and compression.
• Data coded according to application layer protocols are
then encapsulated into one or (occasionally) more
transport layer protocols (such as TCP or UDP), which
in turn use lower layer protocols to effect actual data
transfer.
• Since the IP stack defines no layers between the
application and transport layers, the application layer
must include any protocols that act like the OSI's
presentation and session layer protocols.
• E.g. SMTP, FTP, SSH, HTTP etc.

5. Transport layer (host-to-host):
• This is where flow-control, error-correction, and
connection protocols exist, such as TCP.
• Its responsibility includes end-to-end message
transfer independent of the underlying network,
along with error control, segmentation, flow
control, congestion control, and application
addressing (port numbers).
• End to end message transmission or connecting
applications at the transport layer can be
categorized as connection-oriented, implemented
in TCP, or connectionless, implemented in UDP.

6. Internet layer (internetworking):
• The internet layer has the task of exchanging datagrams
across network boundaries.
• This layer defines the addressing and routing structures
used for the TCP/IP protocol suite. The primary protocol in
this scope is the Internet Protocol, which defines IP
addresses.
• In the Internet protocol suite, the Internet Protocol
performs two basic functions:
 Host addressing and identification: This is accomplished with a
hierarchical addressing system (see IP address).
 Packet routing: This is the basic task of sending packets of data
(datagrams) from source to destination by sending them to the
next network node (router) closer to the final destination.

7. Link layer:
• The link layer is used to move packets
between the Internet layer interfaces of two
different hosts on the same link.
• The processes of transmitting and receiving
packets on a given link can be controlled both
in the software device driver for the network
card, as well as on firmware or
specialized chipsets.

8. Transmission Control Protocol (TCP):
• Transmission Control Protocol accepts data from a data
stream, segments it into chunks, and adds a TCP header
creating a TCP segment. The TCP segment is
then encapsulated into an Internet Protocol (IP) datagram.
• A TCP segment consists of a segment header and
a data section. The TCP header contains 10 mandatory
fields, and an optional extension field. The data section
follows the header. Its contents are the payload data
carried for the application.
• Connections must be properly established in a multi-step
handshake process (connection establishment) before
entering the data transfer phase. After data transmission is
completed, the connection termination closes established
virtual circuits and releases all allocated resources.

9. TCP Header
Source Port Number (16 bits) Destination Port Number (16 bits)
Sequence Number (32 bits)
Acknowledgement Number (32 bits)
Header
Length
(4 bits)
Reserved
(6 bits)
Unused
U
R
G
A
C
K
P
S
H
R
S
T
S
Y
N
F
I
N
Window Size
(16 bits)
Checksum (16 bits) Urgent Pointer (16 bits)
Options + Padding
Data

10. Internet Protocol (IP):
• Principal communication protocol used for
relaying datagrams across an internetwork using
the Internet Protocol Suite.
• IP manages how packets are delivered to and from
servers and clients. IP defines datagram structures
that encapsulate the data to be delivered.
• It also defines addressing methods that are used to
label the datagram source and destination.
• The Internet Protocol is responsible for addressing
hosts and routing datagrams (packets) from a source
host to the destination host across one or more IP
networks.

11. IP Header
Version (4) IHL (4) TOS (8) Total Length (16)
Identification (16) Flags (3) Fragment Offset (13)
TTL (8) Protocol (8) Header Checksum (16)
Source IP address (32)
Destination IP address (32)
Options or Padding not always
Data (variable)

12. IP address (IPv4)

14. • Class A = 0.0.0.0 – 127.255.255.255
• Class B = 128.0.0.0 – 191.255.255.255
• Class C = 192.0.0.0 – 223.255.255.255
• Class D = 224.0.0.0 – 239.255.255.255
• Class E = 240.0.0.0 – 255.255.255
Private IP addresses
• 10.0.0.0 to 10.255.255.255
• 172.16.0.0 to 172.31.255.255
• 192.168.0.0 to 192.168.255.255

15. Subnet Mask
(Network-1, Host-0)
• Class A: 11111111.00000000.00000000.00000000
(255.0.0.0) / 8
• Class B: 11111111.11111111.00000000.00000000
(255.255.0.0) / 16
• Class C: 11111111.11111111.11111111.00000000
(255.255.255.0) / 24

16. IPv6 (Internet Protocol version 6)
IPV6 includes the following enhancements over
IPV4:
• Expanded Address Space:
• Address auto configuration:
• Increased addressing flexibility:
• Security capabilities:
• Support for resource allocation:
• Improved option mechanism:

17. IPv6 Header

18. IPv6: types and formats
• In next slide

19. Internet RFCs:
• In computer network engineering, a Request
for Comments (RFC) is
a memorandum published by the Internet
Engineering Task Force (IETF) describing
methods, behaviors, research, or innovations
applicable to the working of the Internet and
Internet-connected systems.
• It began in 1969 as a set of working notes
about ARPAnet research and development.

20. RFC Categories
Each RFC has a "category" or "status" designation. The possible
categories are:
1. STANDARD, DRAFT STANDARD, PROPOSED STANDARD
• These are standards-track documents, official specifications of the
Internet protocol suite defined by the Internet Engineering Task
Force (IETF) and its steering group the IESG.
2. BEST CURRENT PRACTICE
• These are official guidelines and recommendations, but not
standards, from the IETF.
3. INFORMATIONAL, EXPERIMENTAL
• These non-standards documents may originate in the IETF or may
be independent submissions.
4. HISTORIC
• These are former standards that have been actively deprecated.