OSI MODEL and DTE-DCE DESIGN

Standard 802.3

CSMA/CD (Ethernet)

The Lower Layers

Data link layer and Physical Layer

Session Layer (OSI)

Establishes and maintains end-to-end bidirectional flows between endpoints. Includes managing transaction flows.

The Upper Layers: Application Layer​

FTP (Ports 20/21) HTTP (port 80), HTTPS (Port 443), POP3(Port 110) IMAP (Port 143) RTP( PORTS 5004/5005) SIP ( Ports 5060/5061) SMTP (Port 25) SNM(port 161) SSH (port 22) TELNET (Port 23) DNS(port 53) DHCP (Port 67/68) TFTP (Port 69) SMB( Port 445) RDP (Port 3389)

The OSI Model​

Helped vendors to create interoperable network devices and software in the form of protocols or standards The model uses layers and is the key to developing and troubleshooting networks​

Standard 802.1

LAN/MAN Management ( and Media Access Control Bridges)

The Lower Layers: Physical Layer​

Layer 1 of the OSI model​ Sends and receives information in the form of bits (which come only in values of 0 and 1)​ Communicates directly with the various types of actual communication media; for example:​ Audio tones​ State transitions (changes in voltage from high to low or low to high)​

The Lower Layers: Network Layer​

Layer 3 of the OSI model​ Manages logical device addressing​ Tracks the location of devices on the network and determines the best way to move data​ Transports traffic between devices that are not locally attached​

The Lower Layers: Transport Layer​

Layer 4 of the OSI model ​ Segments and reassembles data into a data stream​ Services handle data from the upper layer applications and unite it onto the same data stream​

The Upper Layers: Presentation Layer​

Layer 6 of the OSI model It presents data to the Application layer and is responsible for data translation and code formatting

Standard 802.2

Logical Link Control

Modulation Techniques​

Modulation: The process of varying one or more properties of a waveform

Data Encapsulation​

N/A

Protocol Data Unit (PDU)​

OSI model that refers to a group of information added or removed by a layer of the OSI model ​ Each layer in the model uses the PDU to communicate and exchange information, which can only be read by the peer layer on the receiving device and is then handed over to next upper layer after stripping​

The Layered Approach​

Physical layer, Data Link Layer, Network layer, Transport layer, Session Layer, Presentation Layer, Application Layer

The Upper Layers: Session Layer​

Simplex - One direction Half Duplex- Only one direction will be allowed through at a time Full-duplex - travels in both direction simultaneously

Physical Layer​

The layer's connectors and different physical topologies or the physical cabling structure​ *** Remember the Bus, Star, Ring, and Mesh topologies from the last lecture ***​

The Lower Layers: Overview​

The lower layers define how the actual data is transmitted from end to end​

The Upper Layers: Overview​

The top three layers define the rules of how the applications working within host machines communicate with each other as the well as with end users​ know anything about networking or network addresses​

Standard 802.4

Token Passing Bus

Standard 802.5

Token Passing Ring

Standard 802.11

Wireless LAN

Standard 802.16

Wireless Metropolitian Area Network (WiMax)

Standard 802.15

Wireless PAN

The Lower Layers: Common IEEE 802 Standards (Data Link Layer)

each standard of 802 has a topic