2/6/2015

1

What is an internet ?• TCP/IP protocol suite -> TCP/IP -> Internet

• A set of interconnected networks

• The Networks can be completely different– Ethernet, ATM, WiFi etc.…

• TCP/IP protocols provide the syntatic and semantic rules for communication.

1OPM 2OPM

OSI and Protocol StackOSI Model TCP/IP Hierarchy Protocols

7th

Application Layer

6th

Presentation Layer

5th

Session Layer

4th

Application Layer

4Transport Layer

3rd

Network Layer

2nd

Link Layer

1st

Physical Layer

Transport Layer

Network Layer

Link Layer

Link Layer : includes device driver and network interface cardNetwork Layer : handles the movement of packets, i.e. RoutingTransport Layer : provides a reliable flow of data between two hostsApplication Layer : handles the details of the particular application 3OPM

Internet Protocol Architecture

RTP

TCP UDP OSPF

BGP

SNMPDNSTELNETFTP

SMTP

HTTPPing

ICMP

RIP

LANs PPPATM FR

TCP UDP OSPFICMP

IP (IPv4, IPv6), IPSec (Encryption)

10/100BaseT Dedicated B/W: DSx, SONET, ...

Circuit-Switched B/W: ISDN, ...

CDPD

Wireless4

OPM

Short forms Corresponding full form

NDP Neighbor Detection Protocol

NAP Network Address Protection

POP Post Office Protocol

ISP Internet Service Provider

IMP Internet Message Processor

TIP Terminal IMP

FR Frame Relay

5

PPP Point to Point Protocol

CDPD Cellular digital Packet data

OSPF Open Shortest Path First

RIP Routing Information Protocol

RTP Real time Transport Protocol

BGP Border Gateway Protocol

STCP Stream Control Transmission Protocol

RSVP Resource Reservation ProtocolOPM

Short forms Corresponding full form

DNS Domain Name System

FTP File Transfer Protocol

HTTP Hyper Text Type Protocol

SMTP Simple Mail Transfer Protocol

SNMP Simple Network Management Protocol

VoIP Voice over IP

NAT Network Address Translation

6

VPN Virtual Private Network

VPI Virtual Path Identifier

VCI Virtual Channel/Connection Identifier

ATM Asynchronous Transmission Mode

IGMP Internet Group Management Protocol

ICMP Internet Control Message Protocol

IP Internet Protocol

TCP Transmission Control ProtocolOPM

2/6/2015

2

Packet Encapsulation The data is sent down the protocol stack at transmitterEach layer adds header to SDU passed from upper layerAt receivers the headers are removed in reverse order

22Bytes 20Bytes 20Bytes 4Bytes

46 to 1500 Bytes 7OPM

Link Layer

• It includes (PHY) guided transmission lines (parallel wires, coaxial cable, wave guide, optical fiber etc.) and wireless channels.

• Line coding, Channel coding & Modulation techniques

• Multiple Medium access like TDMA, FDMA, CDMA, OFDMA, CSMS/CD, CSMS/CA, Aloha, Slotted Aloha

• T1, T2, E1 etc. carrier systems (Frame formation for multiplexing)

• ARP, RARP, InRP, NDP, OSPF, Tunnels (L2TP), PP, Media access (Eathernet, DSL, ISDN, FDDI etc.)

8OPM

Internet layer

• Responsible addressing of end to end devices• Sends data in individual packets• Routs packets towards destination node (routing)

• Maximum size of packet is determined by the networks• Maximum size of packet is determined by the networks– Fragmented if too large from upper layer– Aggregation / Concatenation if too small packets from upper layer

(used during tunnelling to reduce overhead size)

• Ex. Protocols are IPv4, IPv6, ICMP, IPSec etc.

9OPM

Transport layer

• Fragmentation of bit stream (packet formation)

• Traffic flow control in network

• In-order and out of order packet transmission (TCP/ UDP)

• Ensure reliable data transmission between Source and destination nodes

• Ex. Protocols are TCP, UDP, RSVP etc.

10OPM

Application Layer

• Application specific protocols like– IP address allocation:- Static and dynamic (DHCP) scheme

– DNS, FTP, HTTP(Web), SMTP, SNMP, Telnet (remote login) etc.

– Voice and video over IP

– Gateway, Mobile IP, NAT, VPN

11OPM