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RE: 1310 nm vs. 1550 nm links greater than 40 km

Title: RE: 1310 nm vs. 1550 nm links greater than 40 km

As a PMD supplier, I agree with your statements.  The SONET infrastructure is in place and for 40km and greater distances, the 1550nm solution is the only way to go.

 I am interested in seeing any jitter data to support multable regeneration without SONET compliant transmit jitter for the long reach applications.  The VSR applications may not need the jitter as stringently specified if no regeneration is to be done.  I would like to see some feed back on this from the group.


Raj Savara
Network Elements Inc.

-----Original Message-----
From: Bruce Tolley [mailto:btolley@xxxxxxxxx]
Sent: Wednesday, May 31, 2000 2:06 PM
To: vipul.bhatt@xxxxxxxxxxx; stds-802-3-hssg@xxxxxxxx
Subject: Re: 1310 nm vs. 1550 nm links greater than 40 km


We have an objective as a task force to support a distance of at least 40
km over SM fiber.

On the basis of discussions with multiple customers especially service
providers over the last year, I have determined that the market requirement
exists to support distances of 50 to 70 km on SM fiber.

Therefore, I support the PMD that can go much further than 40 km and attach
to existing infrastructure: 1550 nm serial.


Bruce Tolley
Enterprise Line of Business
Cisco Systems

At 12:11 PM 5/31/00 -0700, Vipul Bhatt wrote:

>I would like to respond to a couple of comments made on this
>reflector about the possibility of using 1310 nm wavelength for 40
>km Serial links. I think we should stay with 1550 nm.
>Following a presentation I gave at the 10GEA Santa Clara meeting,
>and also during Serial SIG discussions, the feedback I have received
>from many members is that for Metro Area Networks, it is desirable
>to be able to extend the link distance beyond the stated 40 km goal.
>Metro Area links capable of supporting distances beyond 40 kms will
>be a significant potential application of 10G Ethernet. This does
>not mean that we need to include optical amplifiers or dispersion
>compensation blocks in the standard, only that our link should be
>compatible with them. Compatibility with long distance
>infrastructure tilts the balance in favor of 1550 nm. Limiting the
>operation of this link to 40 kms will be like clipping the wings of
>10G Ethernet.
>If you ask the question - "Do we want a link that is the lowest cost
>solution for 40 kms, or do we want a link that is more expensive but
>capable of plugging into the long distance infrastructure?" - my
>recommendation is to choose the latter.