Networking Notes 1 PDF

1\) Purpose of Routers and Switches: OSI Layers and Forwarding Decisions Router: Purpose: Connects multiple networks and directs data packets between them, enabling communication between devices on different networks (e.g., between your home network and the Internet). OSI Layer: Operates at Layer...

1\) Purpose of Routers and Switches: OSI Layers and Forwarding Decisions Router: Purpose: Connects multiple networks and directs data packets between them, enabling communication between devices on different networks (e.g., between your home network and the Internet). OSI Layer: Operates at Layer 3 (Network Layer) of the OSI model. Forwarding Decision: Uses IP addresses to determine the best path for a packet to reach its destination. This is achieved by consulting routing tables and applying routing protocols like OSPF, BGP, or RIP. Switch: Purpose: Connects devices within a single network (e.g., a LAN) and facilitates communication between them. OSI Layer: Operates primarily at Layer 2 (Data Link Layer) but can also operate at Layer 3 (Layer 3 switches). Forwarding Decision: Uses MAC addresses in a device\'s network interface card (NIC) to forward frames to the appropriate destination within the same network. 2\) Purpose of a Network Interface Card (NIC): Definition: A hardware component, typically built into a device, that provides the physical and logical interface to connect to a network. Purpose: Converts data from the device into electrical, optical, or radio signals for transmission over a network and vice versa. OSI Layers Involved: Physical Layer (Layer 1): Handles signal transmission. Data Link Layer (Layer 2): Deals with MAC addresses and framing data. 3\) Why Use a VPN? Definition: A Virtual Private Network (VPN) creates a secure, encrypted tunnel between a device and a network over the Internet. Purpose: Security: Protects data from eavesdropping by encrypting it. Privacy: Hides the user\'s IP address and location. Access: Allows remote access to private networks and bypasses geographical restrictions on content. Use Cases: Secure remote work, accessing region-locked content, and protecting sensitive communications. 4\) Define Fault Tolerance and Its Implementation in a Network Fault Tolerance: The ability of a system or network to continue functioning in the event of a component failure. Implementation in Networking: Redundancy: Use of multiple network devices (e.g., routers, switches) and paths to avoid single points of failure. Load Balancing: Distributes traffic across multiple servers or connections to ensure availability. Failover Mechanisms: Automatically switches to a backup device or path if the primary fails. RAID: Protects data storage by replicating it across multiple drives. High Availability Protocols: Examples include HSRP (Hot Standby Router Protocol) and VRRP (Virtual Router Redundancy Protocol). 5\) How a Packet-Switched Network Works: Definition: A network where data is broken into small packets that are routed independently to their destination. Key Steps: Data Division: Data is divided into packets. Routing: Each packet contains source and destination IP addresses and is routed individually based on network conditions. Reassembly: Packets are reassembled at the destination in the correct order. Advantages: Efficient use of bandwidth, scalability, and fault tolerance. Example: The Internet is a packet-switched network where protocols like IP and TCP handle addressing and reliable delivery.