Hub vs. Switch vs. Router
The functions of the three devices — the router, switch and hub — are all quite different from one another, even if at times they are all integrated into a single device. Which device do you use when?
What is a Router?
A router is a device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP’s network. Routers are located at gateways, the places where two or more networks connect. Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.
What is a Switch?
In networks, a device that filters and forwards packets between LAN segments. 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.
What is a Hub?
A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.
The Differences of Router, Switch and Hub in Networking
Hub, its role can be simply understood as connecting some machines to form a local area network. The switch (also known as the exchange hub) role and the hub is roughly the same. But the two are different in performance: the type of shared bandwidth used by the hub, and the switch is exclusive bandwidth.
So that a lot of the machine or the amount of data is large, the two will be more obvious. The router and the above two are significantly different, and its role is to connect different network segments and find the most appropriate network data transmission path, it can be said that under normal circumstances, little demand for individual users. The router is generated after the switch, just as the switch is generated after the hub, so the router and the switch also have some contact, not completely independent of the two devices. The router overcomes the shortcomings of the switch that cannot route packets.
In general, the main differences between routers and switches are reflected in the following areas:
(1) The work level is different
The initial switch is the data link layer of the OSI / RM open architecture, which is the second layer, and the router is designed to work at the network layer of the OSI model. Because the switch works on the second layer (data link layer) of the OSI, it works relatively well, and the router works on the third layer (network layer) of the OSI, and can get more protocol information. The router can make more intelligent forwarding decisions.
(2) Data forwarding is based on different objects
The switch uses the physical address or MAC address to determine the destination address of the forwarding data. And the router is the use of different network ID number (IE IP address) to determine the data forwarding address. IP address is implemented in the software, describes the network where the device is located, and sometimes the third layer of the address is also called the protocol address or network address. MAC address is usually hardware comes by the network card manufacturers to allocate, and has been cured to the card to go, in general, cannot be changed. The IP address is usually automatically assigned by the network administrator or the system.
(3) The traditional switch can only split the conflict domain, cannot split the broadcast domain; and the router can split the broadcast domain
The network segments connected by the switch still belong to the same broadcast domain. Broadcast packets are propagated on all network segments connected to the switch, which in some cases can lead to traffic congestion and security vulnerabilities. The network segments connected to the router are assigned to different broadcast domains, and the broadcast data does not pass through the router. Although the third layer of the switch has a VLAN function, you can also split the broadcast domain, but between the sub-broadcast domain is not communication between the exchange between them still need a router.
(4) The router provides a firewall service
The router only forwards packets of specific addresses, does not transmit packets that do not support routing protocols, and transmit packets of unknown target networks, thus preventing broadcast storms.
Switch is generally used for LAN-WAN connection, the switch belongs to the bridge, is the data link layer equipment, some switches can also achieve the third layer of the exchange. The router is used for WAN-WAN connections, which can solve the forwarding of packets between heterosexual networks and act on the network layer. They only accept input packets from one line and then forward to another line. These two lines may belong to different networks and use different protocols.
In contrast, the router’s function is more powerful than the switch, but the speed is relatively slow, expensive, the third layer switches both wire-speed forwarding packet capacities, but also a good control of the router function, it can be widely used.
After reading the above explanation, you have some understanding of on the switches, hubs and routers. The current use of the main switch, the combination of the use of the main router, the specific combination can be based on specific network conditions and needs to determine.