Networking 101by : Eliran Ben-Zikri

Welcome to the amazing world of computer networking, I hope you’ll find this presentation informative and interesting.

Networking – A bunch of devices with cool green LEDs that when combined all together allows computers to exchange data

Networking 101History

60,000 Years ago – People started to Speak5,000 Years ago – People started to Write600 Years ago – Please started to publish50 Years ago – The Internet was born

Networking 101History

WWW was invented in 1989 by Tim Berners-Lee. The entire World-Wide-Web used to be just one computer

Networking 101Facts

In 1999, 38M People had broadband Internet.

Today, 1.2B have in on their mobile devices

Networking 101Facts

14.3 Trillion webpages are live on the Internet

2.7 Billion People (40% of the world’s population) are Online.

Internet? Say what?How did it all start?

Back in the 70’s, many vendors developed many types of computers, each has it’s own set of protocols and architecture

an IBM Computer could only talk to an IBM computer

No standards, No compatibility TCP/IP & OSI model we’re combined to

help creating the world you know today

OSI ModelThe Layers of the Internet

The Open System Interconnect Model

Wait, What?

OSI ModelKey Principles

Divides Networking to 7 Layers Each layer takes care of a very specific

job Each Job is not too Complicated Passes the data onto the next layer. Defines “What”, Not “How”

OSI Model1 Model To Rule Them All

ApplicationPresentation

SessionTransportNetworkData LinkPhysical

שכבת האפליקציהשכבת התצוגהשכבת השיחהשכבת התובלהשכבת הרשתשכבת הערוץשכבה פיזית

The physical layer does not understand anything but bits: The signal comes to it in the form of pulses and is transformed into 0's and 1's.Examples:Physical Equipment, Cables, Connectors, NICsBit Sync, Work RateHubs, Repeaters, USB, Bluetooth, SDH, DSLEncodingParallel VS. Serial

OSI Model#1 - Physical Layer

RCVTRS…110100101110010011101…

Puts some sense to the bits, turning them into Frames, Bridging between Layer 1 & 3 (LLC & MAC), Connecting between Hosts in the LAN – No IP’s, Just MAC’s.Examples:CRC – Error HandlingARP TableCollisions and BroadcastsMAC AddressesSwitches, LAN, ATM, VLANs

OSI Model#2 – Data-Link Layer

1

2

3 6

5

4

Responsible for packet forwarding, Routing, Transferring data from a source to a destination host via one or more networks, while maintaining Quality-Of-Service functions

Connecting two or more LANs all togetherExamples: Inter-Networking (Internet = Collection of LANs 7 WANs) IP Protocol (Connectionless), ICMP, IPSec, IPX QOS, Routing Packets, WAN

OSI Model#3 – Network Layer

Provides end-to-end communication services for applications within a layered architecture of network components and protocols, Between Ports.

Examples: Connects between Applications Reliabile/Unreliable Connection (VoIP vs HTTP) Flow Control Multiplexing TCP, UDP, Segments

OSI Model#4 – Transport Layer

Provides the mechanism for opening, closing and managing a session between end-user application processes

Examples: Full/Half Duplex Sync RPC, SCP

OSI Model#5 – Session Layer

Responsible for the delivery and formatting of information to the application layer for further processing or display.

Examples: Data Conversion Encryption & Decryption ASCII, Terminal, Telnet, AFP

OSI Model#6 – Presentation Layer

Value CodeA 65B 66C 67D 68E 69F 70

The user interface, Responsible for displaying data and images to the user in a human-recognizable format and to interface with the presentation layer below it.

Examples: SSH, FTP, HTTP, SSL, DNS NFS, SIP, SMB, SMTP, RDP LDAP, POP, IMAP, SNMP REST, Web Applications

OSI Model#7 – Application Layer

OSI ModelEncapsulation

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data

Data

Data

DataTransport Header

DataNetwork Header

DataData Link Header

Data

OSI Model#7 – Application Layer

ApplicationPresentation

SessionTransportNetworkData LinkPhysical

ApplicationPresentation

SessionTransportNetworkData LinkPhysicalPhysical

Data LinkNetwork

Networking 101DNS

DNS – Domain Name Server/Service It translates easily memorized domain names to the numerical IP addresses Hierarchical!www.eToro.com -> 91.220.30.150Openbook.eToro.com -> 91.220.30.151

Client

LocalName Server

Root Name Server

IP

IP

Name

Name

Networking 101DNS

Client

LocalName Server

Root Name Server

IP

IP

Name

Name

Networking 101NAT

NAT – Network Address Translation Private IP’s <-> Public IP’s One-to-One, One-to-Many

Source NAT: In -> OutDestination NAT: Out -> In

Networking 101VLAN

VLAN – Virtual LAN Partitioning a Switch to several virtual networks A router is needed for Inter-LAN communication Software rather than Hardware

Each Packet is tagged withA VLAN number, and OnlyTrunk ports or the sameVLAN ports can accept theseFrames (Layer 2)

Networking 101Wireless

Wi-Fi/WLAN based on IEEE 802.11 specs Uses wireless access points (WAPs) Usually operate in the unlicensed spectrum near

2.4 GHz. MIMO – Multiple Input, Multiple Output

802.11a 54 Mbps max, 75 feet max, uses 5 GHz band - Rare802.11b 11 Mbps max, 45 meter max, 2.4 GHz, lowest cost – The

Past802.11g 54 Mbps max, 45 meter max, 2.4 GHz band – The Popular802.11n 600 Mbps max, 70 meter max, 2.4 or 5 GHz band, MIMO –

Rising802.11ac 1 Gbps max, 70 meter max, 5 GHz band, MIMO – The

Future

Networking 101The END

Thank You for Listening!

Wanna know more? Just ask.

Contact me @ eliranbz@etoro.com