Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

RE: [10GBASE-T] Technical feasibility: AutoNegotiation


Perhaps someone can give me a quick pointer on how we are going to address
the issue of <100m cable plants that meet ISO 11801 specs not being able to
support 10GBASE-T.

For example, I have a building full of CAT5e and CAT6 cables. The cables
were installed to specification. Now, all I see are patch panels and wall
jacks. I don't have a record of which cable is how long, or what its
electrical specs are.

The current Auto-Negotiation protocol supports HCD resolution which means
that the link, if configured to 10GBASE-T, will resolve to that speed if
both ends of the link support it. However, if the cable (85m of CAT6) does
not, the link will bounce up and down as it negotiates to speed, then fails
to link. Maybe even worse is the link that actually comes up, but operates
unreliably due to thermal variation causing changes in parametric values and
suffers excessive BER or drops link occasionally.

What is the fix?

Do I test the wire in advance of using 10GBASE-T?
Do we fix the Auto-Negotiation protocol to automatically drop speed if the
SNR gets too low to guarantee the BER?

If these have already been addressed, please feel free to just send the URL
to the presentation. 


Dan Dove
HP ProCurve Networking