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

Phil Stracchino alaric at metrocast.net
Sun Apr 6 09:46:07 CDT 2008

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

It's megabits, remember, not megabytes.

I have gotten an honest 97Mbit/s data rate across my local 100Mbit 
network.  That's about 12 MB/s.  If GigE can manage 900Mbit/s actual 
throughput, that's 112MB/s.  So if SBUS tops out at 200MB/s, it should 
take GigE traffic just fine.  If that's 200Mbit/s, then GigE on SBUS 
isn't going to work too well.  :)

   Phil Stracchino, CDK#2     DoD#299792458     ICBM: 43.5607, -71.355
   alaric at caerllewys.net   alaric at metrocast.net   phil at co.ordinate.org
          Renaissance Man, Unix ronin, Perl hacker, Free Stater
                  It's not the years, it's the mileage.

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