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RE: Working with Larry!

>  From: R karam [mailto:rkaram@xxxxxxxxx]
>  Sent: Wednesday, May 10, 2000 11:56 AM
>  To: stds-802-3-pwrviamdi@xxxxxxxx
>  Cc: ldmiller@xxxxxxxxxxxxxxxxxx
>  Subject: Working with Larry!
>  Hi Larry
>    Thank you for asking- I am encouraged.
>  Cisco's proposal has the following A, B sections.
>  A- Use the Signal pair 1,2 and 3,6 to deliver power on a new switch.
>  B- Use unused pair (4,5 and 7,8 ) to deliver power for mid-span.

Intuitively, this seems to add complexity and I can not fathom
why we would want to use different pairs depending on the 
location of the power insertion. Given our objective of detecting power on
the same pairs that it is inserted, this would require twice the amount of
DTE-detection circuits and raise the issue of how to deal with switch vs
mid-span insertion conflicts (ie: The switch sends Fat-Link-Pulses down
12,36 and gets confirmation to send power while the mid-span sends its
signals down 45,78 and gets confirmation on its pairs). This sounds like
un-necessary complexity.

If you are conceding that using the unused pairs for mid-span is a better
alternative than using the data pairs, please explain to me why we should
use the data pairs for switch-based power insertion.

Simplicity, and consistency would argue that we should just apply power in
the unused pairs at both locations and reduce the number of alternatives by


Dan Dove
HP ProCurve Networks