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.
A passive hub serves simply as a conduit for the data, enabling it to go from one device (or segment) to another. So-called intelligent hubs include additional features that enables an administrator to monitor the traffic passing through the hub and to configure each port in the hub. Intelligent hubs are also called manageable hubs.
A third type of hub, called a switching hub, actually reads the destination address of each packet and then forwards the packet to the correct port.
What is a Hub?A hub is used in a wired network to connect Ethernet cables from a number of devices together. The hub allows each device to talk to the others. (Hubs aren't used in networks with only wireless connections, since network devices such as routers and adapters communicate directly with one another, with nothing in between.)
Hubs are such simple devices — they require no configuration, and have no manuals — that their function is now included in other devices such as routers and modems.
Examples of hubs.
Available NETGEAR hubs are shown here on the NETGEAR North American Marketing Site.
In the same place that hubs used to appear in networks, switches can usually be substituted. This will give better performance, and many additional features. To understand the differences see Selecting Between the Types of Hubs and Switches.
One hub feature for advanced users, is that, since all Ethernet traffic passes through all hub ports, a hub can be used to easily "sniff" a network, an advanced troubleshooting technique. Without otherwise reconfiguring the network, a hub can be inserted that will pick up all broadcast, unicast and multicast traffic A sniffer on a switch port will not see unicast traffic that's not going through that particular port.
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