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Thanks for the good questions. Let me present the rationale for the choices in the table.
The 10x10G (optical wavelengths) 40km 1310nm (DML or ML) alternative is white because no HSSG participant has indicated they are actively investigating it. I can’t comment on why others are not looking at this, but to us this alternative makes no sense compared to 10x10G 40km 1550nm. It incurs steep additional fiber loss, without solving a dispersion problem. At 1550nm 10G has a modest path penalty over a 40km distance, as quantified for example in the 10GE-ER standard.
The 4x25G 10km 1310nm alternative is under active investigation; see for example presentations from us and OpNext at the last HSSG meeting. That is why it’s shaded green.
I am assuming that your comment that early implementations of 100G will be based on 10x10G is referring to the electrical interface (since you then comment on mux/de-mux complexity.) I agree with your assessment; 25G electrical interface speeds are more appropriate for follow-on implementations.
From: Ali Ghiasi [mailto:email@example.com]
The 100GE Technical Feasibility Alternatives table only covers the two
proposed HSSG LAN reach objectives; 10km and 40km. There is currently no
WDM network objective in the HSSG. (In fact, a straw poll at the
meeting to not have a HSSG long haul PMD reach was supported.) So to
keep the coveted green shading we would like to encourage active
investigation efforts towards the use of serial techniques for the LAN
In any case, I look forward to seeing your serial PHY contributions at
the next meeting.
From: Marcus Duelk [mailto:firstname.lastname@example.org]
Sent: Wednesday, April 04, 2007 12:06 PM
Subject: Re: [HSSG] <HSSG-FOAH> Meeting
thanks for the update. I am not speaking for a component vendor
so I don't know whether my feedback here can be considered as
a solution being "under active investigation". However, from a system
vendor's perspective I think that the serial solution (the last two rows
of your table) only makes sense for a WDM network which would
be at 1550nm and at reaches of 40km and beyond. These fields are
currently white but they are, at least from our perspective, under
investigation ... I will make further contributions on the serial PHY at
the next meeting(s).
During today's Fiber Optic Ad Hoc call we discussed updating the SMFalternatives table. We simplified the table entries to three keyqualifiers that are required to enable technical feasibility. Theupdated table is enclosed. Any comments on the proper assignment of
qualifiers will be appreciated.
100G - 1310nm alternatives (shaded green) continue to be under activeinvestigation.
see during upcoming HSSG meetings. At this point we are not making anyselection between the alternatives.