how can USB 1.1 handle 10/100?

[bluemax]

I thought USB 1.1 could only handle 1.2 Megabit... how the heck can it handle a 10/100 USB network interface??
Maybe my numbers are botched.... 😕

 

[Jeff7]

I thought it was 12Mbit? That's the 10 part, but it won't do the 100. You'd need USB 2.0 for that.

 

[Adul]

Originally posted by: bluemax
I thought USB 1.1 could only handle 1.2 Megabit... how the heck can it handle a 10/100 USB network interface??
Maybe my numbers are botched.... 😕

10 Mbps = 1.25 MB/sec
100 Mbps = 12.5 Mb/sec
12 Mbps = 1.5 MB/sec


off course this is all thearitical

 

[bluemax]

Yes, 12Mbit sounds closer than 1.2........ Still, I wonder why they can call it a 10/100 NIC if it can only *really* handle 10 Mbit?
Other than the fact it'll peacefully exist on a 100Mbit network. 😛

 

[kingbob]

USB 1.1 doesn't handle 10/100. It can barely do 1/10...

 

[RSMemphis]

Because it's a standard. It just means it understands the 100 MBit protocol, which can important for a hub (if you have all 100 devices on there).
Does not mean it goes that fast.

Why do I use a 100 MBit ethernet connection to my router which bottlenecks at DSL speeds? 🙂

 

[John]

Originally posted by: RSMemphis
Why do I use a 100 MBit ethernet connection to my router which bottlenecks at DSL speeds? 🙂

I would venture to say that when you finish downloading that 100MB file and want to xfer it to your other PC on the network, you would rather take advantage of the ~12MB/sec thruput of the 100Mbit card. 😉

 

[buleyb]

The xfer rates are able to match in theory, but there is overhead problems with USB that doesn't let ethernet signals travel at 'equivilent' speeds...so it'll feel slower, however it will do the job, and even for a broadband connection of 1.5/768, you shouldn't really see it...

 

[Barnaby W. Füi]

Originally posted by: RSMemphis
Because it's a standard. It just means it understands the 100 MBit protocol, which can important for a hub (if you have all 100 devices on there).
Does not mean it goes that fast.

yup.

usb handles 12mbit, so in theory it can do the 10mbit, but with overhead and all that it might not quite reach it. it definitely won't get near 100mbit, but it'll play nice and connect at 100mbit with other 10/100 devices.

and btw kingbob, what is 1/10? 😉

 

[Demon-Xanth]

I'm going to chime in with "the USB connection becomes the limiting factor". There were 10/100 cards for ISA (very rare), but often the ISA bus limited the connection speed. Consider that PCI can get saturated by a GBit ethernet card.

I can't wait until PCI-X comes into the mainstream, because then we'll have more headroom on the expansion bus.