Minimum distance fir single mode fibre between 2 cisco switches

[steve-gates]

Good Morning

  Could anyone enlighten me on the minimum distance of singlemode fibre between 2 cisco switches using GLC-LH-SM sfp modules before you need to use attenuators. I can fine plenty of information regarding maximum distance but nothing for minimum. The reason being is that I don't want to burn out the sfp's and have to buy new ones !!..

   Many Thanks

      Steve

[Latchum Naidu]

Hi Steve,

Single-mode fiber allows only one mode of light to propagate through the fiber, whereas multimode fiber allows multiple modes of light to propagate through the fiber.

And The minimum distance between two connected stations is 6.56 feet (2 meters).

Please rate the all helpfull posts.
Regards,
Naidu.

[steve-gates]

Thanks for the prompt reply, Just to be certain are you saying that attenuators are not required on short runs of fibre?.. I am just concerned about burning out the fibre modules with single mode fibre.

  Thanks

[Latchum Naidu]

I am not sure but I guess attenuators also required in single mode fiber.

Please rate the all helpfull posts.
Regards,
Naidu.

[vmiller]

You really need to check the transmit/receive power levels of your gbics.

its reasonably safe to assme that the recieve level of "B" will be very close to its corresponding transmit level at the other end.

If thats within the specifications of the reciever, then fine. If its not, the by all means get attenuators.

[Michael Odom]

If you run is really short use a multi-mode patch cable.  They will work with the GLC-LH-SM (see http://www.cisco.com/en/US/docs/routers/7200/install_and_upgrade/gbic_sfp_modules_install/5067g.html#wp34124).  A 10-12m patch cable should be fine, and just coil up any excess.  I wouldn't worry about attenuators unless you are using the high-power ZX optics.