[rescue] Gigabit Ethernet SBus & Gigabit Ethernet Sun 420R/220R

Joshua Boyd jdboyd at jdboyd.net
Sun Apr 6 07:58:39 CDT 2008

On Apr 6, 2008, at 5:47 AM, Steve Sandau wrote:

> Tom "spot" Callaway wrote:
>> On Sat, 2008-04-05 at 23:37 -0400, Joshua Boyd wrote:
>>> On Apr 5, 2008, at 11:27 PM, Tom "spot" Callaway wrote:
>>>> On Sat, 2008-04-05 at 23:03 -0400, Earl D. Baugh Jr. wrote:
>>>>> Two Gigabit ethernet questions....
>>>>> Did anybody ever make a Gigabit ethernet SBus card that ran across
>>>>> twisted pair?
>>>> Wouldn't that be a bit silly, since SBUS maxes out at 200 MB/s  
>>>> (64 bit
>>>> bus)? Or is it bridging to PCI to get around that somehow?
>>> So, basically, you are pointing out that SBUS can do about 2.5  
>>> times  the bandwidth that one would realistically get from GigE?   
>>> Why is  that silly then?
>> Ehh, I suppose. I was thinking 1000 MB/s, but that's not realistic.
> I would hope that gigE would max out at more like 500MB/s, but I  
> have not worked with gigE and jumbo frames enough to know.

GigE is supposedly capable of going close to 100 MB/s a second, with  
jumbo frames.

> 100MB ethernet maxes out at what, 70MB/s or 80MB/s under ideal  
> conditions, or is that even too optimistic?

Typically one uses MB for megabyte, and Mb for megabit.

FastE is 100Mb, but in average circumstances in the real world it  
only does about 7.5-9MB.

GigE is 1000Mb, and is rumoured to be capable of doing 80MB+, but  
that requires fairly good hardware.

Some people say that it isn't worth upgrading to GigE if you can't  
get 10 times faster than FastE, but I wonder why people think that a  
4-6x upgrade for older machines isn't worthwhile?

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