The document provides an overview of the Transmission Control Protocol (TCP) and Internet Protocol (IP), detailing their history, functionality, and how they facilitate error-free communication over networks. It explains TCP/IP as a crucial networking standard and the significance of different protocol layers, including IP datagrams and error-handling mechanisms like ICMP. Additionally, it covers various Internet addressing schemes and applications such as Telnet, FTP, and the World Wide Web.

1. Transmission Control Protocol
(TCP) / Internet Protocol (IP)

2. Overview of TCP/IP
• Oldest networking standard developed for US
department’s ARPANET
• Most popular network protocol
• Allows reasonably efficient and error – free
transmission
• A file transfer protocol , sends large files
uncorrupted across unreliable networks
• Compatible with a variety of data link protocols
hence popular

3. An Internet
F
A
e
5
1 d
f
B a 4
2
3 c E
b
C
D
A, B, C, D, E, F –host (computers)
1, 2, 3, 4, 5 – physical networks
a, b, c, d, e, f – routers/gateways
For TCP/IP, the same internet appears differently. TCP/IP considers all
interconnected physical networks as one huge network (1+2+3+4+5)

4. TCP/IP and OSI model
Data units
known as
Application Applications
Application
NFS
TFTP
SMTP
TELNET
SNMP
DNS
FTP
Presentation Message
RPL creates
Session
Transport layer (2protocols) TCP UDP H
Segment or
user diagram
ICMP IP (Supports 4 protocols) Creates
Network H
layer ARP RARP Datagram
Encapsulated
Data link layer H
Protocols defined by the Frame
underlying networks
Physical layer
Bits

5. NETWORK LAYER
• ICMP (Internet control message protocol) -
handles error & controls messages
• IGMP
• ARP (Address resolution protocol) – obtaining the
physical address of a mode when the internet
address is known
• RARP (Reverse address resolution protocol) –
allows a host to discover its internet address when
it knows only its physical address

6. Internet Protocol (IP) -1
• Transmission mechanism used for TCP/IP
• Unreliable & connectionless datagram
protocol
• Assumes the unreliability of the underlying
layers & gives best to get a transmission
through to its destination
• For good quality IP must be paired with a
reliable protocol like TCP

7. Internet Protocol (IP) – 2
• IP transports data in packets known as
datagrams
• IP functionality in a limited way is not a
weakness
• IP provides bare-bone transmission
functions ; frees the user to add only those
facilities necessary for a given application;
allows for maximum efficiency

8. IP Datagram
20-65536 bytes
20-60 bytes
(a) Datagram
Header Data
VER HLEN Service type Total length of the
VER – IP Datagram 16 bits
4 bits 4 bits 8 bits (2 byte field)
Version Flags Fragmentation
Identification 16 bits
HLEN – 3 bits Offset 13 bits
Header length
Time to live Protocol Header checksum
8 bits 8 bits 16 bits
Source IP address
Destination IP address
Option (b) Header

9. IP datagram- 1
• Service type : defines how the datagram
should be handled; includes bits that define
the priority of the datagram; also contains
bits that specify type of service the sender
desires such as the level of throughput,
reliability and delay
• Total length : can define up to 65,536
bytes;two byte field.

10. IP datagram- 2
• Flags : Bits in the flags deal with fragmentation.
(Datagram can/cannot be fragmented; can be the first,
middle or last fragment etc.)
• Fragmentation offset : A pointer shows the offset of the
data in the original datagram
• Time to live : This field defines the number of hops a
datagram can travel before it is discarded; source host,
when it creates the datagram sets this field to an initial
value; when the datagram travels through the internet
router by router each router decrements this value by 1. If
this value becomes 0 before the datagram reaches its final
destination, the datagram is discarded. This prevents a
datagram from going back & forth between routers

11. Internet address - 1
• Protocol : field defines which upper layer protocol
data are encapsulated
• Source address, destination address : Each field is
a four byte(32 bit) Internet address. It identifies
the original source & final destination of the
datagram respectively.
• Options : The field gives more functionality to the
IP datagram. It carries field that control routing,
timing, management and alignment.

12. Internet address - 2
• Addressing : Physical addresses are on NICs. It
identifies individual devices. The internet
requires an additional addressing constituent :
An address that identifies the connection of a
host to its network
Each internet consists of four bytes (32 bits)
defining three fields :
I. Class type
II. Netid
III. Hostid

13. Internet address
- each internet consists of four bytes (32 bits)
defining three fields :
1) Class type
2) Netid varying lengths & depends on the
3) Hostid Class of the address
Class type
Netid Hostid

14. Internet classes
byte 1 byte 2 byte 3 byte 4 Address
Class A 0 Netid Hostid Hostid Hostid Lowest
Class B 1 0 Netid Hostid
Class C 1 1 0 Netid Hostid
Class D 1 1 1 0 Multicast address
Class E 1 1 1 1 0 Reserved for future use

15. Class range of internet addresses
From To
Netid Hostid Netid Hostid
Class A 0 .0.0.0 127 .255 . 255. 255
Netid Hostid Netid Hostid
Class B 128.0 0.0 127 .255 . 255. 255
Netid Netid Hostid
Class C 192 . 0.0 . 0 127 .255 . 255. 255
Hostid Hostid
Class D 224 . 0 . 0 . 0 127 .255 . 255. 255
Class E 240 . 0 . 0 . 0 127 .255 . 255. 255

16. Network & hosts addresses in an
139.6.0.1
internet
139.6.0.2 139.6.0.3
Network 1
C1 C2 C3
139.6.0.0
139.6.0.4
178.5.2.3 G 171.26.05.08 G Gateway
R
C10 Gateway C6 Router
178 .5.0.0 171.26.01.09 C3 C4
Network
3
C7 Network 2
171.26.01.05 171.26.01.06
171.26.00.0
C9 C8
182.2.0.0
178.5.2.1 178.5.2.2

17. ARP request/response
ARP packet
Router
or host
ARP packet One of the nodes
questions about the HostHos
1 Host 2 Host 3
Host responds
physical address of identifying itself
a node. IP address it as the right node
gives & gives the
physical address

18. UDP Datagram Format
variable
8 bytes
Header Data
Source port Destination port
address 16 bits Address 16 bits
Total length Clocksum
16 bits 16 bits

19. UDP
Delivers a
datagram
IP
Host-to-host protocol
Source host Destination host

20. Port-to-port addresses
1 3 4
2
p 1 pp 2 pp 3 pp 4 pp pp app
p
a a
ap
ap a a a
TCP or UDP TCP or UDP
IP IP
Data Link Data Link
Physical Physical

21. TCP segment
Header Data (a) Datagram
Source port address Destination port address
16 bits 16 bits
Sequence number
32 bits
Acknowledge number
HLEN –
32 bits
u s p r s
Header length HLEN Reserved r c s s y f l
Window size
4 bits 16 bits g k n t n n 16 bits
Control checksum Urgent pointer
16 bits 16 bits
Options and padding

22. Client/server Paradigm
Server
Client Server
TCP/IP program
program
Result

24. Using TELNET to login
User working
online
New Delhi
Calcutta
Terminal Host
Mumbai
Hyderabad
Banglore
Chennai

25. Steps involved in TELNET
(remote login) - 1
Remote
Terminal Local host host
(Real)
TELNET TELNET
Client server
TCP/IP
Standard
Standard
code
code

26. Steps involved in TELNET
(remote login) - 2
1. TELNET client transforms the output from the
actual terminal to standard code
2. TELNET server in the remote host receives the
information in the standard code
3. TELNET server will transform the information
into character accepted by remote host
4. The remote host is pooled into thinking that a
terminal is locally connected to it. (in other
words a virtual terminal is connected to the local
host)

27. FTP
User Protocol
interface Control connection interpreter
Protocol
TCP/IP Data
interpreter
Data Transfer
Data connection unit
transfer unit
Local host Remote host
Local Remote
disk disk

28. Local procedure call
C program
calling the User application
open
program
Function
is used here
C program
to access a Local
disk procedure
Local Local
Disk host

29. Remote procedure call - 1
C program
Calling the
Open
Function
Is used here
NFS NFS
client Server
C program
C program
to access a
disk RPC RPC
Client Client
Local Local Remote
Disk host TCP/IP host Local
Disk

30. Remote procedure call - 2
1. A program issues a call to the NFS client
process. NFS client formats the call for the
RPC client and passes it.
2. RPC client transforms the data to a format
called XDR.(external data presentation) &
provides the interface with TCP/IP
transport mechanisms.

31. Remote procedure call - 3
3. At the remote host, RPC server retrieves the call
translates it out of XDR and passes it to the NFS
server.
4. NFS server relays the call to the remote disk.
5. The remote disk finally responds as if to a call &
opens the file to the NFS server. Similar process
is followed in the reverse order to work in the
opposite way.

32. Electronic Mail
User A User B
(Sending & Receiving)
Interface Interface
User User
agent agent
Spool Mail boxes Mail boxes Spool
Alias Database
Database Alias
expansion or disk
Or disk expansion
Mail transfer Mail transfer Mail transfer
Mail transfer agents Agents
agents Agents
(MTA) (MTA) (MTA)
(MTA)
Internet

33. SNMP Network 3
Router R3
Manager
Router R2 Router R4
Managed
(Agent)
Router R1 Manager
Router R5
Router R
Network 1
Routers R1 to R4 are
Managed
Managed (Agent)
(Agent)

34. World Wide Web
Web server B (Denmark)
Web server A (Mumbai)
Web server C (Japan)
Web server D (Chennai)

35. World wide web
Requires
A functional
architecture
A structural
architecture
A navigational
architecture

36. A Functional Architecture
<html> WWW.Server Proxy server
<head> http://www.datamation.com
<title> DATAMATION From &
Plugin </title> to the
</head>
<body> internet
<hp> newswire</hl>
<hl> DATAMATION
Magazine </hl>
<hl> Media kit </hl>
LAN HTML documents
interpreted by browsers Fire wall

37. A structural architecture
D: WWW.Server
http://www.datamation.com
Newswire
Live wire
DATAMATION MANAGEMENT
Table of contents
Feature index
Cover story
Management
Desktops
Networks
Software
Servers

38. Browser architecture
• Many commercial browsers exist
• These interpret and display a web
document. Each of these use the same
architecture
• Browser has three parts :
1. Controller
2. Client programs
3. Interpreters

39. Browser architecture
HTML
INTERPRETERS
BROWSER
controller CGI
Java
HTTP FTTP GOPHER TELNET SMTP

40. Static documents
• Fixed content documents are created and
stored in a server
• Client accesses the document, a copy of the
document is received
• User can use a browsing program to display
the document
• User cannot change the contents;but the
contents can be changed in the server

41. Static documents
URL Request for a
document
Document
Response
Client Server
Web document

42. Dynamic documents -1
• These do not exist in predefined format
• Documents are created by a web server
when a browser requests the document
• When the request arrives, the web server
runs an application program to create the
dynamic document
• Server then returns the output in response to
the browsers request for document

43. Dynamic documents - 2
• Contents of document varies as these are
created for each request. Time and date are
types of dynamic information.
• Client can request that the server run a
program in UNIX and send the result back

44. Dynamic documents
URL Request for a
document
Document
Response
Client Server

45. Dynamic documents
Steps
• Client requests for
running a program.
• Running the program
creates document.
• Respond

46. Active documents
Produce the
document D
D
P
Request for a
URL
document
P1 Copy of the program
Client Response P1 sent Server
Running the
program P1

47. Active documents
Steps
• Client requests for a
copy of the program
• Copy of the program
is sent by server.
• Running the program
and creating the
document at the
client’s end.

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