Upload
shravan-wadhwa
View
221
Download
0
Embed Size (px)
Citation preview
7/30/2019 Unit 1osi Model
1/19
OSI Layers
Presented By
bhuvanesh kumar
7/30/2019 Unit 1osi Model
2/19
7/30/2019 Unit 1osi Model
3/19
OSI means Open System Interconnect model.
Developed by the International Organization for Standardization in1974.
It consists of seven layers.
Each layer has a different but specific processing function.
OSI Model
7/30/2019 Unit 1osi Model
4/19
OSI Model Layers
Application
Presentation
Session
Transport
Network
Data Link
Physical
Layer - 7
Layer - 6
Layer - 5
Layer - 4
Layer - 3
Layer - 2
Layer - 1
Upper Layeror
Software Layer
Lower LayerorHardware Layer
Heart of OSI
7/30/2019 Unit 1osi Model
5/19
Data flow from Transport Layer
Data
Data
Data
DataTH
Segment
Application
Presentation
Session
Transport
Network
Data Link
Physical
7/30/2019 Unit 1osi Model
6/19
Network Layer
Network Layer isresponsible for providing bestpath for data to reach thedestination. Logical Addressingworks on this layer. Router is aNetwork Layer device.
It is divided into two parts Routed Protocols
e.g. IP, IPX, Apple Talk. Routing Protocols
e.g. RIP, IGRP, OSPF, EIGRP
Application
Presentation
Session
Transport
Network
Data Link
Physical
Network
7/30/2019 Unit 1osi Model
7/19
Routed Protocols
Hello!
How areyou ?
192.168.1.1 192.168.1.2
A B
Segment
Segment
Source IP192.168.1.1
Destination IP192.168.1.2
Source IP192.168.1.1
Destination IP192.168.1.2
Segment
Hello!
How areyou ?
7/30/2019 Unit 1osi Model
8/19
Routing Protocols
A
www.zoomgroup.com
7/30/2019 Unit 1osi Model
9/19
Data flow from Network Layer
Data
Data
Data
Segment
Segment
NH
e.g. Router
Packet
Application
Presentation
Session
Transport
Network
Data Link
Physical
7/30/2019 Unit 1osi Model
10/19
Datalink Layer
Datalink Layer isdivided into two Sub Layers :
LLC Logical Link ControlIt talks about Wan protocols e.g.
PPP, HDLC, Frame-relay
MAC Media Access ControlIt talks about Physical Address.It is a 48 bit address i.e. 12 digit
Hexadecimal Number.It is also responsible for ErrorDetectionDevices working on Data LinkLayer are Switch, Bridge, NIC.
Application
Presentation
Session
Transport
Network
Data Link
Physical
Data Link
7/30/2019 Unit 1osi Model
11/19
Error Detection CRC Check
Hello!How are
you ?
Packet
Packet
Source MAC00-20-18-C0-07-71
Destination MAC00-20-18-C0-07-72
000003243422222896965543499323434349943446323111143333300000324342222289696554349932343434994344632311114Error Detected
192.168.1.100-20-18-C0-07-71
192.168.1.200-20-18-C0-07-72
A B
PC-ACRC No. 33333
PC-BCRC No. 11114Error Detected
For Error Correction
Contact Source Transport layer
7/30/2019 Unit 1osi Model
12/19
Error Detection CRC Check
Packet
Packet
Source MAC00-20-18-C0-07-71
Destination MAC00-20-18-C0-07-72
00000324342222289696554349932343434994344632311114202020000032434222228969655434993234343499434463231111420202
Source MAC00-20-18-C0-07-71
Destination MAC00-20-18-C0-07-72
Packet
Hello!How are
you ?
192.168.1.100-20-18-C0-07-71
192.168.1.200-20-18-C0-07-72
A B
7/30/2019 Unit 1osi Model
13/19
e.g. Switch
Data flow from Data Link Layer
Data
Data
Data
Segment
DH
Packet
DT
Application
Presentation
Session
Transport
Network
Data Link
Physical
PacketPacketFrame
7/30/2019 Unit 1osi Model
14/19
Physical Layer
Physical Layer isresponsible for electrical,mechanical and procedural checks.Data will be converted into Binary(i.e) 0s & 1s. Data will be in theform of electrical pulses if it is
Coaxial or Twisted Pair cable and inthe form of Light if it is Fiber OpticCable.
Devices working at Physical Layerare Hubs, Repeaters, Cables,Modems etc.
Application
Presentation
Session
Transport
Network
Data Link
PhysicalPhysical
7/30/2019 Unit 1osi Model
15/19
Physical Layer Example
Frame
Frame
10101010101010101010101010101010
Frame
Hello!
How areyou ?
A B01010110101010101010101011010101101010101010101010010101101010101010101010110101011010101010101010100101011010101010101010101
7/30/2019 Unit 1osi Model
16/19
Data flow from Physical Layer
Data
Data
Data
Segment
Packet
Frame
Bits
e.g. Hub
Application
Presentation
Session
Transport
Network
Data Link
Physical
7/30/2019 Unit 1osi Model
17/19
Segment
Packet
Frame
A B
Packet
Data
Data
Data
Bits
Data
Segment
Data Encapsulation & De-capsulation
Packet
Data
Data
Data
Application
Presentation
Session
Transport
Network
Data Link
Physical
Application
Presentation
Session
Transport
Network
Data Link
PhysicalBits
DH DT
NH
THSegment
Packet
DT PacketDH DTDH
NH Segment NH
TH Data TH
Frame Packet
7/30/2019 Unit 1osi Model
18/19
Application
Transport
Internet
NetworkAccess
Comparing OSI with TCP/IP Layers
OSI Layers TCP/IP Layers
Application
Presentation
Session
Transport
Network
Data Link
Physical
7/30/2019 Unit 1osi Model
19/19