Router, Switch, Firewall, Ports, and Load Balancer — Must Watch to understand the backbone Network

Routers, Switches, Firewalls, Ports, and Load Balancers Detail

1️⃣ Router

A router is a Layer-3 network device that connects multiple networks and decides the best path for data to travel.
It uses IP addresses to forward packets between LAN, WAN, and the Internet.
Routers perform routing using static or dynamic protocols like OSPF, BGP, EIGRP, and RIP.
They support NAT (Network Address Translation) to allow private IPs to access the Internet.
Modern routers also provide VPN, QoS, ACLs, and SD-WAN capabilities.
In enterprises, routers act as the gateway between internal networks and ISPs.

2️⃣ Switch

A switch is primarily a Layer-2 device that connects devices within the same network.
It uses MAC addresses to forward frames efficiently.
Switches reduce collisions by providing dedicated bandwidth per port.
They support VLANs to logically separate networks for security and performance.
Advanced switches work at Layer-3, enabling inter-VLAN routing.
They are the core and access foundation of enterprise networks.

3️⃣ Firewall

A firewall is a security device that monitors and controls traffic based on security rules.
It operates at Layer-3, Layer-4, and Layer-7.
Firewalls protect networks from unauthorized access, malware, and cyber threats.
They support stateful inspection, deep packet inspection, and application control.
Next-Generation Firewalls (NGFWs) include IPS, URL filtering, SSL inspection, and threat intelligence.
Firewalls are deployed at network perimeters, data centers, and cloud environments.

4️⃣ Network Ports

Ports are logical communication endpoints identified by port numbers.
They work at the Transport Layer (Layer-4) using TCP or UDP.
Common ports include 80 (HTTP), 443 (HTTPS), 22 (SSH), 53 (DNS), and 3389 (RDP).
Ports help systems identify which service or application the traffic belongs to.
Firewalls and routers use ports to allow or block specific traffic.
Port management is critical for security and application performance.

5️⃣ Load Balancer

A load balancer distributes traffic across multiple servers to ensure high availability.
It prevents any single server from becoming overloaded.
Load balancers operate at Layer-4 (TCP/UDP) and Layer-7 (HTTP/HTTPS).
They improve performance, scalability, and fault tolerance.
Features include health checks, session persistence, and SSL offloading.
Load balancers are widely used in data centers, cloud, and enterprise applications.