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Re: [802.3BA] Longer OM3 Reach Objective

I've been preaching Single Mode to the Desk for going on 10 years now.  The fiber is cheaper and has much higher ultimate bandwidth, connectors are not too much different, but transceivers have always been the gating item.  In a sense it's "chicken or the egg" circle - standards such as 802.3 only recognize SM as the long distance (10 km) solution, and MMF as the short distance (<300 meter), so SM transceiver vendors don't spend time trying to come up with ways to make a low cost 300 m SM transceiver since there's no market. 
It may be that alignment physics dictate that SM will always be enough more expensive to keep MMF as the preferred short distance solution, but let's recognize the way technology is chosen for standards guides product development. 

From: Petar Pepeljugoski [mailto:petarp@US.IBM.COM]
Sent: Monday, March 17, 2008 10:34 AM
Subject: Re: [802.3BA] Longer OM3 Reach Objective


The reason why there is still a deployment of MMF is the cost. SMF modules (10km) for 100 GbE is more than one magnitude higher cost than MMF 100m over OM3. For that reason, MMF will continue to play an important role, until there is parity in cost between the two solutions.



Petar Pepeljugoski
IBM Research
P.O.Box 218 (mail)
1101 Kitchawan Road, Rte. 134 (shipping)
Yorktown Heights, NY 10598

phone: (914)-945-3761
fax:        (914)-945-4134

Mikael Abrahamsson <swmike@SWM.PP.SE>

03/17/2008 09:42 AM
Please respond to
Mikael Abrahamsson <swmike@SWM.PP.SE>

Re: [802.3BA] Longer OM3 Reach Objective

On Mon, 17 Mar 2008, Petar Pepeljugoski wrote:

> We have seen this happen with copper - lengths are shrinking, and MMF is
> filling the void for ever shorter links. The same will inevitably happen
> to MMF on the longer side of the links. where SMF will be more
> competitive.

I am very curious as to why someone would do new deployments of MMF today.
I know quite a few in the ISP business who has decided to go solely to SMF
to try to cut down on number of spare parts and types of cables. Cost of
cables and installation seems very similar.

Is there really an end user cost benefit with MMF today? Also,
theoretically, will MMF survive the next leap in speed again, isn't it
just a matter of time before everybody has to switch to SMF anyway?

Mikael Abrahamsson    email: