switch or hub ? whats the differance
Pam's comment on the Discussion Board is nearly correct. Hubs (or, in the Ethernet environment, properly called concentrators) are dumb in that all traffic that comes in from one port is broadcast to all ports while switches are smart in that they set up direct one-to-one communication between the transmitting port and the receiving port so that only those two are "busied out" with that conversation. However, where we diverge is whether a small network--such as a household network--would make good use of a switch rather than a concentrator. copyright ybarra-cgm
To explain, the problem with concentrators is that only one station may broadcast at a time. Thus, if one station is trying to reach out to the Internet and another is trying to print to a network-attached printer (or a shared printer attached to another workstation), only one of these transmissions may occur. The other has to wait for the first conversation to end before it can start what it wants to do. This is done by sensing the line and detecting whether there is data on the line or not. Now, what can happen is that two stations can detect nothing on the line at the exact same time and then both try to transmit. This causes what is called a collision and, thus, none of the data gets through. Instead, a "jam signal" is sent out to reset all ports and have them each start sensing for traffic again at a random time. The first one who senses nothing gets the chance to transmit. Round and round it goes with random access, so in a large network with only concentrators, there could be significant delays before something as simple as a printout is generated.
In a switched network, when the station transmits, the switch receives the data, looks at the destination address and then creates the virtual connection between the two ports. If the destination port is busy, the switch stores the transmission until the port is available and then establishes the communication link and leaves it connected until the conversation is complete. Instead of having only one conversation possible at a time, the switch can manage multiple conversations at the same time and have there be greater efficiency and throughput because there is very little chance for collision (read: nearly non-existent since it is a one-to-one link between two stations and the two will always know who should be transmitting and who should be receiving).
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Pam is correct that any network today (most of which are 100Mbps Fast Ethernet networks) will be able to handle the comparatively slower speed of any Internet connection (the fastest connection that I've seen is 50Mbps, so half the speed of a home network…at best). So, why might one want to get a switch instead of a concentrator? Well, first of all, it is hard to find a concentrator nowadays. What is typically available is a 5-port or 8-port switch and considering that such a switch can now be purchased for as little as $25, it makes no sense to look for a concentrator. Second, it does allow more efficient use of the network as I explained above. ybarra-cgm.com
Now the fun part is figuring out which switch you want to purchase: do you go with four ports, five ports, eight ports, etc? Also, do you want Fast Ethernet (100Mbps) or Gigabit (1Gbps)? Well, the first question is easy: you need to count the number of connections that you will need to make and whether you intend to need more connections in the future. As 8-port switches are typically only a few dollars more than 5-port switches, I would recommend going with at least an 8-port. Also, be aware that they can be daisy chained, so if you need more than eight ports, it might be cheaper to get two 8-port switches and daisy chain them rather than get one 16-port switch. That will result in 14 available ports--as one on each switch is needed for the cable that runs between the two switches--rather than 15 ports on a single 16-port switch but to save money, it could be the better option. Switches can be daisy chained again and again, so you can keep adding more layers if necessary. Be aware, though, that each level adds distance from your router, printer, and other devices, so communication between those resources could be hampered. In such a case, investing in larger switches would be preferable. My advice would be not to go more than about three or four levels deep in the daisy chain. ybarra-cgm.com
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The second question can be more perplexing if you do not know the capabilities of your devices. In that case, I would probably err on the side of speed: go for the gigabit switch. That way, if you have devices that can make use of the gigabit speed within your home, you are not hampering them by installing only Fast Ethernet. If nothing can do gigabit, then you have what you need for the future when you get something faster and you are still getting Fast Ethernet today (as switches are backward compatible). Gigabit switches are slightly more expensive. (I just recently picked up a Fast Ethernet 8-port switch for a client for $25 and a gigabit switch for myself for $40.) So, the price is not that much higher and you get ten times the bandwidth capacity, so I recommend going with the gigabit switch if you can spare the extra few dollars. copyright ybarra-cgm
Oh, don't worry about managed as opposed to unmanaged switches. Managed switches are for larger networks that utilize specific configurations to help improve corporate network traffic efficiency and are not anything about which you need to be concerned for your presumably small home-based network. Thus, do not bother with the expense of a managed switch.
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