networking 101 english
TRANSCRIPT
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
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