Re: [802.3_4PPOE] Are diode bridges really needed (2).pptx
Hi Christian:
What is a “4-pair
crossover” cable? Is a modular cord that is wired T568A on one end
and T568B on the other? If
so and this cord is used as designed, it would ensure that the same pair
combination is "split" (e.g. terminated to pins 4,5 and 3,6)
on both ends of the channel.
All the best - Val
From:
Christian BEIA <christian.beia@xxxxxx>
To:
STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx,
Date:
02/05/2014 01:55 AM
Subject:
Re: [802.3_4PPOE]
Are diode bridges really needed (2).pptx
Thank you Goran,
I was not aware about this
case.
Is there anyone who can tell
if those “4-pair crossover” cables are standardized or not?
Thank you
Best regards
Christian
From: Hauer, Goran (Goran) [mailto:ghauer@xxxxxxxxx]
Sent: Friday, January 31, 2014 4:41 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Are diode bridges really needed (2).pptx
Hi guys
I haven't participated in
any meetings live, but I have been subscribing to this list for quite some
time. Great work you guys!
When I saw this presentation
however I must say that I have seen (and used) crossover cables intended
for 1000BASE-T that crosses all four pairs, whether they are standardized
or not that I can't tell, but they are out there.
Best regards,
/Goran
Från: Chad Jones (cmjones) [mailto:cmjones@xxxxxxxxx]
Skickat: den 31 januari 2014 16:14
Till: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Ämne: [802.3_4PPOE] FW: Are diode bridges really needed (2).pptx
Christian, the reflector should be able
to handle attachments up to 2MB in size.
All, I am forwarding this on behalf of
Christian. He is looking for some help to decide if we can pursue removal
of auto-polarity in the PD.
Christian, I am going to forward this to
Pat Thaler (I’m not sure that she’s subscribed to our reflector). I will
copy you. It was her comment in AF that eventually led to us mandating
autoMDIX support.
Chad Jones
MGR, HW ENG, Cisco Systems
Chair, IEEE P802.3bt 4PPoE Task Force
From: Christian BEIA <christian.beia@xxxxxx>
Date: Friday, January 31, 2014 at 6:02 AM
To: Yair Darshan <YDarshan@xxxxxxxxxxxxx>,
Fred Schindler <fred@xxxxxxxxxxxxxx>,
Dave Dwelley <ddwelley@xxxxxxxxxx>,
"Picard, Jean" <jean_picard@xxxxxx>,
Chad Jones <cmjones@xxxxxxxxx>
Cc: "Yseboodt, Lennart (lennart.yseboodt@xxxxxxxxxxx)"
<lennart.yseboodt@xxxxxxxxxxx>,
"Abramson, David" <david.abramson@xxxxxx>,
"Kousalya Balasubramanian (kousalya.balasubramanian@xxxxxxxxx)"
<kousalya.balasubramanian@xxxxxxxxx>
Subject: Are diode bridges really needed (2).pptx
Hi Guys,
I’m trying to find out if
having a defined voltage polarity at the PD PI is an achievable goal.
Please look at the short presentation
in attachment. It summarizes the spec we have today.
After this brief research,
my understanding is the following:
About Alt-A: reverse polarity
at the PD happens only if a MDI-X cable is used and there is no auto-detect
mode
About Alt-B: reverse polarity
at the PD should never happen.
Are those assumption correct?
If they are correct, I would
like to understand if auto-detect mode is a common feature or it is something
“advanced”.
I can imagine that a Midspan
probably won’t have an auto-detect feature. But what is the reason for
using MDI-X cables between the midspan and the PD?
Thank you for any comment
Best regards
Christian
P.S.
Chad,
I’m not using the reflector
since I’m not sure I can attach presentations there.
If it is ok I will forward
this email to the reflector.