CCNA NOTES.pdf

COMPUTER NETWORK Two or more computers that are connected with each other for the purpose of communicate and share resources with each other. KEY POINTS: Connectivity: Allow devices (Computer, printer, smartphones etc.) to connect and communicate over wired or wireless medium. Data Sharing: Sharing...

COMPUTER NETWORK Two or more computers that are connected with each other for the purpose of communicate and share resources with each other. KEY POINTS: Connectivity: Allow devices (Computer, printer, smartphones etc.) to connect and communicate over wired or wireless medium. Data Sharing: Sharing information (files, documents, multimedia) between devices. Resource Sharing: Enables sharing of hardware resources like printers, storage drives among connected devices. Communication: Supports various forms of communication such as email, instant message, and video conferencing. TYPES OF NETWORK LAN: Local Area Network  Covers a small localized area such as a home, office or building  Typically used for connecting computers and devices within a limited space  High speed connection(Ethernet / WiFi) WAN: Wide Area Network {INTERNET}  Covers a Large geographical area such as city, country or even worldwide.  Connects multiple LANs across long distances  Example: Internet MAN: Metropolitan Area Network  Covers a larger area than LAN but smaller than a WAN such as city or Campus  Used to connect multiple LANs within metropolitan area  Example: A city-wide network used by businesses, universities WAYS OF COMMUNICATION Simplex: One way communication (disc antenna, Radio) Half Duplex: Two way communication but at a time one direction. (walkie talkie) Full Duplex: Real time two way communication.(mobile phone) TYPES OF COMMUNICATION: INTRANET: Private online network only accessible to members within an organization. EXTRANET: Intranet that is partially accessible to people outside the organization Like: there are two branches of one company in different location or remote location. One branch wants to access head office service that time internet is required with the help of ISP. Note: When a private services which is accessed by a remote location office with the help of any third party network then it is known as EXTRANET INTERNET: Global online network that provides information and communication. NETWORK DEVICES: 1. Network Interface Card (NIC):  NIC is the interface between the computer and the network.  It is also known as the LAN card or Ethernet card.  Ethernet cards have a unique 48 bit address called as MAC address or Physical address  MAC address is also called as Physical address or hardware address  The 48 bit MAC address is represented as 12 Hexa-decimal digits  Example:0011:G4F3:635J  Network Cards are available in different speeds  Ethernet (10 Mbps)  Fast Ethernet (100 Mbps)  Gigabit Ethernet (1 Gbps)   SFP (Small Factor Pluggable ) typically refers to fiber optic networks, speeds can vary widely, commonly ranging from 1 Gbps to 100 Gbps or more, depending on the specific technology. 2. ROUTER:  Direct data packets between different networks(ex: Between your home network and the Internet)  Provide Routes. Determine the best path for data to travel across networks  Provides internet connectivity to multiple devices in a network. 3. SWITCH  Connects Devices within a local area network.  Use MAC address to forward data to the correct destination device  Reduces network traffic by only sending data to the intended recipient. 4. MODEM   Converts digital data from a computer into a signal(analog/electrical) suitable for transmission over telephone lines or cable and vice versa  Enable Internet access by connecting to an Internet Service Provider DSL (Digital Subscriber Line), cable fiber modem. 5. ACCESS POINT  Provide Wireless (Wi Fi) connectivity within a network.  Extends a wired network by allowing wireless device to connect.  Used to expand Wi-Fi coverage in large areas 6. FIREWALL  Monitors and controls incoming and outgoing network traffic based on security rules.  Protect a network from unauthorized access and cyber threats  Can be hardware-based or software- based. 7. GATEWAY   Act as a bridge between two different networks often with different protocol.  Translate data between different systems(ex: between a home network and internet)  Often integrated into a router. 8. HUB  Basic Network device that connects multiple devices in a LAN.  Broadcasts data to all connected devices regardless of the recipient.  Less efficient compared to a switch due to network traffic.  OSI layer 1 | Physical Layer 9. BRIDGE  Connects and filter between two or more LAN segments.  Reduces traffic by dividing a network into smaller segments.  Operate at the data link layer of OSI layer. 10. REPEATER  Amplifies or regenerate signals to extend the range of a network.  Commonly used in long distance transmission to avoid signal degradation.  Work in both wired and wireless network.