Hardware capture platforms

David Newman dnewman at networktest.com
Wed Jul 30 18:34:04 CDT 2008


Jon Kibler wrote:

> Hubs are still available that are REAL hubs. I got 4 netgears about a
> year ago and they are still available.
> 
> However, there is a problem with your specification: No hub (that I am
> aware of) can do 1Gbps. All hubs are 10/100 AFAIK.

Grand Junction made a gigabit Ethernet repeater around 1996. It was 
based on the "carrier extension" part of the gigabit Ethernet
spec that allows for half-duplex operation. Carrier extension pads any 
frame shorter than 512 bytes to be 512 bytes long.

For that reason (in case frame size distribution matters), as well as 
the tons of collisions that others have mentioned, I'd also stay away 
from hubs for the OP's needs.

Also, many 10/100 hubs have a 2-port switch to move frames between 
speeds, so it's conceivable that even a "hub" may have multiple 
collision domains.

dn






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