Advanced computer network concept

1. Advanced Computer Networks
Chapter 2 Protocols and the TCP/IP Suite
1

2. Course Objective
 Introducing high speed networks including
gigabit networks.
 Design issues related to IP and TCP/IP and ATM
networks
 Provide up-to-date survey of developments in the
area.
 Performance analysis, congestion control and
provision of QoS to different applications are
also discussed.
Chapter 2 Protocols and the TCP/IP Suite
2

3. Course Outline
 Protocols and the TCP/IP Suite
 TCP and IP
 Frame Relay
 Asynchronous Transfer Mode
 High-Speed LANs
 Queuing Analysis
 Congestion and Traffic Management
 Internet Routing
 Assignment on Different Protocols in
Networking
Chapter 1 Protocols and the TCP/IP Suite
3

4. Chapter 2 Protocols and the TCP/IP Suite
4
Chapter 1
Protocols and the TCP/IP Suite

5. Chapter 2 Protocols and the TCP/IP Suite
5
Introduction
 Layered protocol architecture
 TCP/IP protocol suite
 OSI reference model
 Internetworking

6. Chapter 2 Protocols and the TCP/IP Suite
6
The Need for a Protocol
Architecture
 When computers, terminals and/or other data
processing devices exchange data:
– The Procedures involved to exchange data
between devices can be complex
– High degree of cooperation required between
communicating systems
 See the example in the next slide.

7. Chapter 2 Protocols and the TCP/IP Suite
7
Example: File transfer
 Requires a data path to exist (either a direct link
or via a comm. network)
 Tasks:
– Activate data communication path
– Source determines that destination is ready
– File transfer app at source must ascertain that destination file
management app is ready to store file for user
– File format conversion
 Instead of implementing the logic as a single module, the
task is broken up into subtasks, each of which is
implemented separately.

8. Chapter 2 Protocols and the TCP/IP Suite
8
Layered Protocol Architecture
 Modules arranged in a vertical stack
 Each layer in stack:
– Performs related functions
– Relies on lower layer for more primitive functions
– Provides services to next higher layer
– Communicates with corresponding peer layer of
neighboring system using a protocol
 Ideally, layers should be defined, so that changes in
one layer do not require changes in other layers.

9. Chapter 2 Protocols and the TCP/IP Suite
9
Key Features of a Protocol
 It takes two to communicate – the same set of layered
functions must exist in two systems – peer layers.
 The peer layers communicate by means of formatted
blocks of data that obey a set of rules or conventions
known as a protocol.
 The key features of a protocol are as follows:
– Set of rules or conventions to exchange blocks of
formatted data
– Syntax: concerns the format of the data blocks
– Semantics: Includes control information (coordination,
error handling)
– Timing: speed matching, sequencing

10. Chapter 2 Protocols and the TCP/IP Suite
10
TCP/IP Layers
 Physical – concerned with specifying the
characteristics of the transmission medium, the
nature of the signals, the data rate and related
matters.
 Network access – concerned with the exchange of
data b/n an end system and the network to which it is
attached.
 Internet
 Transport
 Application

11. Chapter 2 Protocols and the TCP/IP Suite
11
TCP and UDP
 TCP:
– connection-oriented
– Reliable packet delivery in sequence
 UDP:
– connectionless (datagram)
– Unreliable packet delivery
– Packets may arrive out of sequence or
duplicated

12. Chapter 2 Protocols and the TCP/IP Suite
12
Figure 2.1

13. Chapter 2 Protocols and the TCP/IP Suite
13
Figure 2.2

14. Chapter 2 Protocols and the TCP/IP Suite
14
Operation of TCP and IP
 IP implemented in end systems and
routers, relaying data between hosts
 TCP implemented only in end systems,
assuring reliable delivery of blocks of data
 Each host on subnetwork has unique IP
address
 Each process on each process has unique
IP port number

15. Chapter 2 Protocols and the TCP/IP Suite
15
Figure 2-3

16. Chapter 2 Protocols and the TCP/IP Suite
16
Figure 2-4

17. Chapter 2 Protocols and the TCP/IP Suite
17
TCP Applications
 SMTP: Simple Mail Transfer Protocol
 FTP: File Transfer Protocol
 telnet: remote login
 HTTP(s)

18. Chapter 2 Protocols and the TCP/IP Suite
18
OSI Reference Model
 Application
 Presentation
 Session
 Transport
 Network
 Data link
 physical

19. Chapter 2 Protocols and the TCP/IP Suite
19
Figure 2.5

20. Chapter 2 Protocols and the TCP/IP Suite
20
Internetworking Terms
 Communication network
 Internet
 Intranet
 Subnetwork
 End system
 Intermediate system (IS)
 Bridge – an IS used to connect two LANs that
use similar LAN protocols. (an Address
Filter)
 Router – an IS used to connect two networks
that may or may not be similar.

21. Chapter 2 Protocols and the TCP/IP Suite
21
Routers
 Internetworking among dissimilar
subnetworks is achieved by using routers to
interconnect the subnetworks.
 Provide link between networks
 Provide for the routing and delivery of data
 Accommodate network differences:
– Addressing schemes
– Maximum packet sizes
– Hardware and software interfaces
– Network reliability

22. Chapter 2 Protocols and the TCP/IP Suite
22
Figure 2-7

23. Chapter 2 Protocols and the TCP/IP Suite
23
Figure 2-8

24. Chapter 2 Protocols and the TCP/IP Suite
24
Figure 2-9

25. Chapter 2 Protocols and the TCP/IP Suite
25
Figure 2-10