What is the difference between a router and a network switch?

Routers and network switches are both crucial components of computer networks, but they serve different purposes and operate at different layers of the network stack. Here are the main differences between them:

1. Functionality:

   - Router: A router is a networking device that connects multiple networks together and routes data packets between them. It operates at the network layer (Layer 3) of the OSI model. Routers make decisions about where to send data based on IP addresses.

   - Switch: A network switch, on the other hand, connects devices within a single network and forwards data packets between them. It operates at the data link layer (Layer 2) of the OSI model. Switches use MAC addresses to determine where to forward data within the local network.

2. Scope:

   - Router: Routers are used to connect different networks, such as connecting a home network to the internet or connecting multiple offices in a wide area network (WAN).

   - Switch: Switches are used within a single network, such as a local area network (LAN), to connect devices like computers, printers, and servers.

3. Addressing:

   - Router: Routers use IP addresses to route packets between networks. They maintain a routing table that maps destination IP addresses to the appropriate network interface.

   - Switch: Switches use MAC addresses to forward packets within a network. They maintain a MAC address table that maps MAC addresses to the port on which each device is connected.

4. Traffic Management:

   - Router: Routers can perform functions such as packet filtering, network address translation (NAT), Quality of Service (QoS) management, and firewalling to control and manage traffic between networks.

   - Switch: Switches primarily focus on efficiently forwarding data within the local network based on MAC addresses. They typically do not perform complex traffic management functions like routers do.

In summary, routers are used to connect different networks together and route traffic between them, while switches are used to connect devices within a single network and forward traffic between them. Routers operate at the network layer and use IP addresses for routing, while switches operate at the data link layer and use MAC addresses for forwarding within a network.