On 02/11/2011 12:21 PM, Jason Hsu wrote:
What are the differences among a switch, hub, and router? I know that they are used in networking, but I don't understand what setups they are appropriate for.
There's going to be a lot of information available on the WWW, but as I understand it:
* A hub typically connects devices on the same sub-network and blindly sends all incoming packets to all devices. Hubs are the lowest-cost means for connecting three or more computers via twisted pair Ethernet. (A cross-over cable is the lowest-cost means for connecting two devices.)
* A switch typically connects devices on the same sub-network, knows which device is which (by MAC address), and sends incoming packets to just those devices that are supposed to receive them. With a wired switch, it is possible for multiple streams of communication to occur simultaneously. (For wireless, there is only one RF spectrum.) Switches can give better performance (and/or security) than hubs, but cost more.
* A router typically connects two or more sub-networks, knows which sub-network is which (by interface IP address and subnet mask), and sends incoming packets to just those sub-networks that are supposed to receive them (per routing tables). Some routers add filter/ firewall/ stateful packet inspection, network address translation (NAT), DHCP server, DNS cache/ proxy, web proxy/ filter, virtual private networking, intrusion detection, etc.. The sky's the limit for features and price. There are many SOHO router/ switch (and/or modem) products in the $100-200 range with enough features to get you operational with minimum effort. If you want to DIY, an x86 PC, 2+ NIC's, and a FOSS *nix distribution is a viable option.
HTH, David