From: Cacca Mucca (caccamucca@gmail.com)
Date: Mon Jul 31 2006 - 03:35:03 ART
Thanks for detailed info.
I think I'll just go with SX and stay away from LX for now.
On 7/28/06, Guyler, Rik <rguyler@shp-dayton.org> wrote:
>
> There's a little more to it than that.
>
> MM fiber has several light pathways called modes. These light pathways
> within the fiber must all be used to get the maximum potential of the
> fiber.
> This is why SX transmitters are typically LED-based, which disperse the
> light across the various modes.
>
> SM fiber has a single light pathway or mode and so the light that travels
> through this type of fiber should be concentrated. Hence the reason why
> LX
> transmitters typically use lasers, which do not disperse light very much
> and
> can concentrate most of the light directly on the single mode. Because
> the
> light is concentrated and not dispersed, it will suffer much less
> attenuation and result in much greater distances.
>
> Using an LX transmitter with MM fiber can work for short distances (this
> will vary due to fiber and termination quality, number of cross connects,
> etc.) but because you are not able to light up all of the modes, this
> combination will suffer from attentuation significantly compared to
> matching
> them up correctly. Fiber mode conditioning cables were developed as a
> middle ground, allowing the use of an LX transmitter on much cheaper (or
> pre-existing) MM fiber. The conditioning cable is a MM patch cable with a
> splice of SM cable on the transmit side so it receives the full capability
> of the LX transmitter. The cable then distributes the LX output over the
> multiple modes of the MM fiber so you get the best of both worlds: a less
> expensive fiber cable plant but better distance numbers than you get with
> SX
> tranmistters.
>
> Rik
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Skinner, Stephen
> Sent: Friday, July 28, 2006 8:30 AM
> To: Cacca Mucca; Cisco certification
> Subject: RE: Running SFP LX/LH over MM Fibers
>
> What wavelength are you using
>
> Multimode simply means the cable is cable of running a wavelength of
> either
> 850 or 1300 or whatever.
>
> It is the circuit packs at either end which dictate what Wave your at.
>
>
> Are you running this on a circuit or back-to-back
>
> If its back to back , then aslong as your GBIC/SPF's match you will be ok
> .
>
> If it's running over a circuit then it depends on how the provider puts
> the
> circuit.
>
> If its an 850 length circuit and you put LH gbic at either end , your
> cisco
> switch won't work.
>
> HTH
>
> Stephen Skinner
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]
> Sent: 28 July 2006 13:09
> To: Cisco certification; Cisco certification
> Subject: Running SFP LX/LH over MM Fibers
>
> *** WARNING : This message originates from the Internet ***
>
> Just want to confirm, I have none to test with, that I'll be able to run
> LX/LH on multimode fibers.
>
> Thanks
>
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