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| indori 2001-05-22, 10:25 am |
| What is this WIRE SPEED. I came around this word in switching.
Which switching method works on WIRE SPEED | |
| AnalogKid 2001-05-22, 10:32 am |
| Cut-through is at wire speed. | |
| strikeattack 2001-05-22, 12:48 pm |
| Wire speed is referring to how fast a switch can get traffic from an input interface to an output interface. In other words, does the switch ASIC introduce any latency in getting the packet to its destination? If not, it is switching at wire-speed. This is a simple, generalized explanation. | |
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| so do u mean to say that wire-speed only exists in the bridge/switch? i mean is it only from entry point to exit point? does it not include the speed to the destination from the sender? just a little clarification pls. | |
| chunder 2001-05-22, 4:57 pm |
| good explanation strike...
it may also be beneficial to mention that wire-speed is not one of the other 2 switching methods, those being:
- store-and-forward
- fragment-free
store-and-forward copies the entire frame into the buffers on the switch, performs some CRCs to check for errors, looks up the mac address in it's table and then passes the frame along it's merry way. so, store-and-forward has the highest latency (and latency varies with frame size) of the 3 switching types but has the best error correction.
fragment-free is a combination of the other 2. the first 64 bytes are copied (because most errors are detected in the first 64 bytes) to the buffers and checked, then the mac address is looked up and then it's sent along its merry way. so, not as fast as cut-through but adds some error correction and faster than store-and-forward.
fragment-free is the default type on the 1900s.
(partially paraphrased from ExamCram, pp94-95) | |
| chunder 2001-05-22, 5:02 pm |
| quote:
Originally posted by gohar
so do u mean to say that wire-speed only exists in the bridge/switch? i mean is it only from entry point to exit point? does it not include the speed to the destination from the sender? just a little clarification pls.
it means that the switch can forward at the speed of the wire, essentially. i.e. if you have a 100Mb network, the switch operating at wire-speed doesn't slow down the data.
quote:
from whatis.com:
wire speed
Wire speed is whatever rate of data transfer a given telecommunication technology provides at the physical wire level. Wire-speed, an adjective, describes any hardware box or function that tends to support this data transfer rate without slowing it down. It's common to refer to functions embedded in microchips rather than in software programming as working at wire speed. switch, router, and other devices are sometimes described by their manufacturers as operating at wire speed. Data encryption and decryption and hardware emulation are software functions that might run at wire speed (or close to it) when embedded in a microchip.
http://whatis.techtarget.com/defini...uery=wire+speed
i hope my URL works. nope. there's that DAMN <br> in it... hell. | |
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| thank u very much as i got my answer. what i infered is that wire speed is the speed with which the frame is recieved and with no/very little latency goes out the desired port. the latency might be nil or very little. is this ok? | |
| chunder 2001-05-22, 5:32 pm |
| quote:
Originally posted by gohar
thank u very much as i got my answer. what i infered is that wire speed is the speed with which the frame is recieved and with no/very little latency goes out the desired port. the latency might be nil or very little. is this ok?
i'd say you're safe in saying that... anyone else? | |
| strikeattack 2001-05-22, 7:02 pm |
| Chunder,
I use whatis.com also. Also, try acronymfinder.com for acronyms. I use these two sites regularly. | |
| chunder 2001-05-22, 8:28 pm |
| quote:
Originally posted by strikeattack
Chunder,
I use whatis.com also. Also, try acronymfinder.com for acronyms. I use these two sites regularly.
whatis.com rocks! i like the acronymfinder.com too... did you do ICND? i thought it a little interesting there's an Alcatel reference in there.... we almost bought Alcatel instead of Cisco.. |
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