From routers to firewalls—discover how every network stays connected скачать в хорошем качестве

From routers to firewalls—discover how every network stays connected

Networking Devices Explained in Detail 1️⃣ Hub A basic device that connects multiple computers in a network. Works on Layer 1 (Physical Layer) of OSI model. Sends incoming data to all connected devices — causing collisions. No intelligence, no filtering, no MAC table. Mostly outdated today. Simple Example: Like shouting information in a room — everyone hears it whether needed or not. 2️⃣ Switch Used to connect devices within the same LAN. Works on Layer 2 (Data Link). Uses MAC Address Table to forward frames only to specific ports. Reduces collisions → faster and more secure. Supports VLANs, STP, PoE etc. Example: Like calling only one person in a room by name — information goes directly to the right device. 3️⃣ Router Connects different networks (LAN to WAN/Internet). Works on Layer 3 (Network Layer). Uses IP addressing and routing protocols (OSPF, BGP, EIGRP). Performs NAT, DHCP, Firewall functions depending on configuration. Example: Like a postal service — finds the best route for sending packets. 4️⃣ Firewall Enforces security rules between networks. Works mainly on Layer 3 & 4, next-gen firewalls also inspect Layer 7. Blocks or allows traffic based on predefined policies. Protects against attacks, malware, unauthorized access. Example: Like a security guard checking who can enter the building. 5️⃣ Access Point (AP) Provides wireless network connectivity. Works on Layer 2. Extends network coverage in Wi-Fi environments. Supports standards like 802.11a/b/g/n/ac/ax. Example: Like a wireless door into the same network your switch uses. 6️⃣ Modem Converts signals between digital (LAN) and analog (ISP line) formats. Used for Internet access via DSL, cable, fiber, 4G/5G. Works on Physical Layer. Example: Like a translator converting spoken language to written format. 7️⃣ Gateway Connects networks using different protocols (IP ↔ VoIP, IPv4 ↔ IPv6). Performs protocol translation. Works across multiple OSI layers. Example: Like a multilingual guide allowing two different language speakers to communicate. 8️⃣ Load Balancer Distributes network traffic across multiple servers. Prevents overload, improves speed & availability. Works on Layer 4–7 depending on type (TCP/HTTPS balancing). Example: Like sending customers to different checkout counters to reduce queue wait time. 9️⃣ Repeater Regenerates and boosts weak signals over long distances. Works on Layer 1. Mostly used in long-distance fiber/Wi-Fi. Example: Like using a megaphone to repeat a message farther. 🔟 Bridge Similar to a switch but older and slower. Connects and filters traffic between network segments. Works on Layer 2. ⭐ Quick Comparison Table (Useful for Slides) Device OSI Layer Function Intelligent? Hub Layer 1 Broadcasts data ❌ Switch Layer 2 Forwards using MAC ✔ Router Layer 3 Routes using IP ✔ Firewall L3–L7 Security filtering ✔✔✔ AP Layer 2 Wireless access ✔ Modem Layer 1 Digital ↔ Analog ❌ Gateway Multi-Layer Protocol translation ✔ Load Balancer L4–L7 Traffic distribution ✔ Repeater Layer 1 Signal boosting ❌ Bridge Layer 2 Segment filtering ✔