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It's a Hub, it's a Switch, it's a Router! 2
- Thread starter Dimandja
- Start date
![[evil]](/data/assets/smilies/evil.gif "[evil] [evil]")
)?
sleipnir214
Programmer
edfair:
Should the phrase "until I was blue in the face" be running through my mind about now?
Want the best answers? Ask the best questions!
TANSTAAFL!!
Should the phrase "until I was blue in the face" be running through my mind about now?
Want the best answers? Ask the best questions!
TANSTAAFL!!
It helps if you know the system well enough that you can set up a test in such a way that they can see it and it will penetrate to their little one track minds.
But maybe, just maybe, I have a problem. I've seen too many cases of fingerpointing and I don't react well to it.
Ed Fair
Give the wrong symptoms, get the wrong solutions.
But maybe, just maybe, I have a problem. I've seen too many cases of fingerpointing and I don't react well to it.
Ed Fair
Give the wrong symptoms, get the wrong solutions.
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1
- #5
I could easily be wrong (networking's not my thing), but here's how I understand them in very layman terms:
Hub - Effectively just wires all of the attached cables together so they can pass data. Not meaningfully "intelligent," and therefor can only deal with one network, and only deal well with devices that are all transmitting and receiving data at the same speed.
Switch - Like a hub, but wires all of the high-speed cables together, and then all of the low-speed cables together, and then "intelligently" speeds up or slows down traffic that passes between them. Still not smart enough to deal with more than one network.
Router - Like a switch, but actually examines the data being passed through the cables and makes "intelligent" decisions about where to move it and how. As such it can connect multiple networks together.
Hub - Effectively just wires all of the attached cables together so they can pass data. Not meaningfully "intelligent," and therefor can only deal with one network, and only deal well with devices that are all transmitting and receiving data at the same speed.
Switch - Like a hub, but wires all of the high-speed cables together, and then all of the low-speed cables together, and then "intelligently" speeds up or slows down traffic that passes between them. Still not smart enough to deal with more than one network.
Router - Like a switch, but actually examines the data being passed through the cables and makes "intelligent" decisions about where to move it and how. As such it can connect multiple networks together.
I might add:
In a hub, the signal is instantly made available at all ports, hence making a hub a bit slow when large amounts of data are transmitted.
In a switch, as the name says, the information is dynamically made present at the active port only, thus acting as a switch, hence being a bit faster than the hub.
;-)
Don't know exactly about the router (yet)... Genumuse's post sounds reasonable.
[blue]An eye for an eye only leaves the whole world blind. - "Mahatma" Mohandas K. Gandhi[/blue]
In a hub, the signal is instantly made available at all ports, hence making a hub a bit slow when large amounts of data are transmitted.
In a switch, as the name says, the information is dynamically made present at the active port only, thus acting as a switch, hence being a bit faster than the hub.
;-)
Don't know exactly about the router (yet)... Genumuse's post sounds reasonable.
[blue]An eye for an eye only leaves the whole world blind. - "Mahatma" Mohandas K. Gandhi[/blue]
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1
- #8
Hubs are repeaters. They send every signal received at every connection to every other connection in the box. They don't operate at any particular network layer. Logically they are LAN devices of which a network consists. Received packets are sent no matter where they belong. There are new "smart" hubs that do more than this, but that's how they started.
Switches inspect the recipient/gateway MAC address of an arriving packet and send the packet out on only one wire, where that recipient is connected (based on automatic discovery of the connected devices). They operate at layer 3 of the network stack. Logically they are LAN devices of which a network consists. Received packets that are already on the correct network segment are discarded. There are new "smart" switches that do more than this, but that's how they started.
Routers inspect the recipient/gateway IP address of an arriving packet and send the packet out only one port, to another network that is closer to the recipient's network (based on routing information programmed by an administrator or dynamically exchanged between routers). They operate at layer 4 of the network stack. Logically they are WAN devices sitting between networks. Received packets that are already on the correct network (or already closer than any other route known to the router) are discarded. There are new routers that do more than this, but that's how they started.
Now there are machines that operate at layer 3 AND layer 4. My descriptions may be basic or somewhat simplified, but they are essentially accurate.
For what it's worth, a hub is electronically faster than a switch. It does not inspect packets and has no queue or CPU in it. If two computers are attached, and one sends a ton of data while the other only receives, the transit time for the hub would be faster than a comparable setup with a switch, and the throughput would be nearly identical.
It is only when network activity is initiated by many computers at once that the weakness of a hub shows up: packets start to "collide" (be sent at the same time) and must be resent. Switches and hubs do not have this problem because they sent traffic to only the intended recipient, from a FIFO queue. They have their only problem, which is that the more traffic there is and the longer the routing tables become, the higher the latency (delay) in forwarding each packet.
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• Every joy is beyond all others. The fruit we are eating is always the best fruit of all.
• It is waking that understands sleep and not sleep that understands waking. There is an ignorance of evil that comes from being young: there is a darker ignorance that comes from doing it, as men by sleeping lose the k
Switches inspect the recipient/gateway MAC address of an arriving packet and send the packet out on only one wire, where that recipient is connected (based on automatic discovery of the connected devices). They operate at layer 3 of the network stack. Logically they are LAN devices of which a network consists. Received packets that are already on the correct network segment are discarded. There are new "smart" switches that do more than this, but that's how they started.
Routers inspect the recipient/gateway IP address of an arriving packet and send the packet out only one port, to another network that is closer to the recipient's network (based on routing information programmed by an administrator or dynamically exchanged between routers). They operate at layer 4 of the network stack. Logically they are WAN devices sitting between networks. Received packets that are already on the correct network (or already closer than any other route known to the router) are discarded. There are new routers that do more than this, but that's how they started.
Now there are machines that operate at layer 3 AND layer 4. My descriptions may be basic or somewhat simplified, but they are essentially accurate.
For what it's worth, a hub is electronically faster than a switch. It does not inspect packets and has no queue or CPU in it. If two computers are attached, and one sends a ton of data while the other only receives, the transit time for the hub would be faster than a comparable setup with a switch, and the throughput would be nearly identical.
It is only when network activity is initiated by many computers at once that the weakness of a hub shows up: packets start to "collide" (be sent at the same time) and must be resent. Switches and hubs do not have this problem because they sent traffic to only the intended recipient, from a FIFO queue. They have their only problem, which is that the more traffic there is and the longer the routing tables become, the higher the latency (delay) in forwarding each packet.
-------------------------------------
• Every joy is beyond all others. The fruit we are eating is always the best fruit of all.
• It is waking that understands sleep and not sleep that understands waking. There is an ignorance of evil that comes from being young: there is a darker ignorance that comes from doing it, as men by sleeping lose the k
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