Router Vs Switch Vs Hub
Router, Switch and even Hub are the terms often used by the network administrator. Today most routers have become something of a Swiss Army knife, combining the features and functionality of a router and switch/hub into a single unit. So conversations regarding these devices can be a bit misleading — especially to someone new to computer networking. The functions of a router, hub and a switch are all quite different from one another, even if at times they are all integrated into a single device. Most of the systems which require network connectivity will use these devices. But, what exactly is the difference between these terms? How do they differ technically? Today I am going to give a short description of these devices from the technical point of view and explain how they are working in the background.
Let's start with Hub. This is the simplest form of networking device. It is working in physical layer (layer 1) of the OSI model. It is just a normal connection point without any intelligence. When a packet arrives at one port, it is forwarded to all the connected ports so that all segments of the LAN can see all packets.
A network switch is a computer networking device that is used to connect many devices together on a computer network. A switch is considered more advanced than a hub because a switch will send msg to the device that needs or request it. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. It uses MAC address for data transmission.
A router is a networking device that connects a local network to other local networks. At the Network Layer of the OSI Model, routers direct traffic and perform other functions critical to efficient network operation. It is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. It uses Full duplex as transmission mode. In the router, every port has its own Broadcast domain. It uses IP address for data tranmission.
| Router | Switch | Hub |
| Network Layer (Layer 3 devices) | Network Layer (Layer 2/3 devices) | Network Layer (Layer 1 devices) |
| LAN, MAN, WAN | LAN | LAN |
| Store IP address in Routing table and maintain address at its own. | Switches use content accessible memory CAM table which is typically accessed by ASIC | Physical device |
| Full duplex | Half/Full duplex | Half duplex |
| In Router, every port has its own Broadcast domain. Separate Collision domains. | Switch has one broadcast domain [unless VLAN implemented] / Separate Collision domain. | One Collision domain / One Broadcast domain. All nodes share the BW of the network. |
| Intelligent Device | Intelligent Device | - |
| Perform NAT | Cannot perform NAT | Cannot perform NAT |
