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GbE Transceivers

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  • 1.  GbE Transceivers

    Posted Jan 23, 2019 10:48 AM

    Hi community.

    I have 850 OM4 multimode fiber optics links deployed between my central building and secondary buildings.

    Is it possible to use Aruba 1G SFP LC LX 10Km SMF Transceivers J4859D (deployed in my central switch core and my distribution switches in the secondary buildings) with these multimode fiber optics links?

    Regards



  • 2.  RE: GbE Transceivers

    MVP EXPERT
    Posted Jan 23, 2019 11:11 AM

    No. OM4 is multimode cable. The SFP+ LC LX module is a longrange module and needs singlemode cabling.

     

    See also the ArubaOS-Switch and ArubaOS-CX Transceiver Guide for details.

    https://support.hpe.com/hpsc/doc/public/display?docId=a00028947en_us



  • 3.  RE: GbE Transceivers

    Posted Jan 23, 2019 11:14 AM

    Hi Marcel,

    Thanks a lot for your answer. What can I do if my multimode links are longer than 550m?

    Regards



  • 4.  RE: GbE Transceivers

    MVP EXPERT
    Posted Jan 23, 2019 11:22 AM

    OM4 cabling is supported to 550 meter on 1Gb links. So based on this you need singlemode building cabling and LX (longrange) SFP+ modules up to 10Km.

     

    A option you can consider is to place an extra switch within the range of 550 meter and uplink again for the next 550 meter. Maybe a sight-to-sight wireless connection is a option for you? But is all up to your personal situation and needs.

     

    See also https://www.lanshack.com/Fiber-Type-vs-Speed-and-Distance.aspx

     



  • 5.  RE: GbE Transceivers

    Posted Jan 23, 2019 03:59 PM

    What about using mode continioning patch cables?

    https://www.cablestogo.com/learning/library/data-center/mode-conditioning-fiber

    Can I use 1000 Base LX transceiver (J4859D) and mode conditioning patch cables to connect buildings through OM4 multimode fiber keeping distance between more than 550 meters and less than 1000 meters?

    Regards

     



  • 6.  RE: GbE Transceivers

    MVP EXPERT
    Posted Jan 23, 2019 04:13 PM

    Hi,

     

    I dont have experience with the mode-conditioning cables, hear about them but thats it. But up to some resource it seem that your are right, also good to known for me, thanks.

     

    please note that the singlemode part of the cable must be put on the transmiting part of the 1Gb LX SFP transceiver. 

     

    https://www.blackbox.nl/nl-nl/page/27251/Informatie/Tech-Info/black-box-explains/fibre-optic-cable/fibre-optic-modeconditioning-cable

    Use Fibre Optic Mode-Conditioning Cable for Gigabit Ethernet longer than 550 meters

    You can run Gigabit Ethernet over up to 2-km-long multimode fibre optic cable. However, the transceiver modules used for long-wave (1310-nm) Gigabit Ethernet (1000BASE-LX) launch only single-mode signals. So if you have multimode fibre cable longer than 550 meters in your existing system, you can use it for Gigabit Ethernet by using Fibre Optic Mode-Conditioning Cables.


    Launching a single-mode laser into the centre of a multimode fibre can confuse the receiver at the other end if multiple signals are generated. Differential Mode Delay (DMD) effects create these multiple signals, which severely limit cable distance lengths for operating Gigabit Ethernet. Fibre Optic Mode-Conditioning Cables offset the single-mode laser launch from the centre of a multimode fibre, which eliminates the multiple signals and enables a launch similar to a typical multimode LED launch.



  • 7.  RE: GbE Transceivers

    Posted Jan 23, 2019 04:21 PM

    Anybody else ?

    I still have some doubts about this. I would really appreciate some advise from HPE Aruba guys.

    Thanks in advance



  • 8.  RE: GbE Transceivers

    EMPLOYEE
    Posted Jan 23, 2019 04:44 PM

    If anything goes wrong with the conditioning cables, TAC is going to ask you to install equipment to the proper specs.  I personally have run into the opposite issue recently where a user had 1 meter of singlemode cable with multimode gbics connecting a controller to a switch and there were alot of errors on the interface.  After trying a bunch of combinations, we had to replace the gbics and the fiber (both to multimode) to stop the errors and stop hundreds of access points from rebootstrapping.

     

    If you have time, you can experiment.  If you do not, just do it right the first time.

     

    EDIT:  There was also a switch between the controller and the real layer3 switch that was a cut-through switch, so none of the errors showed up on that switch, which made figuring out what was wrong even more time-consuming.

     

    It would be interesting to hear what others have done.



  • 9.  RE: GbE Transceivers

    MVP EXPERT
    Posted Jan 23, 2019 04:51 PM

    Agree with cjoseph. See also this hpe support document.

    https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c01932642

     

    As cjoseph say it isnt official listed as supported and not in the

    ArubaOS-Switch and ArubaOS-CX Transceiver Guide Matrix

    Capture3.JPG

     

     



  • 10.  RE: GbE Transceivers

    Posted Jan 23, 2019 05:13 PM

    Marcel, I have already read that manual. In fact, HPE is talking about distances for OM1 and OM2 multimode fiber. What about OM4?, nothing about it?.

    I have heard that some OM4 fiber vendors claim that this fiber optic could support longer distances than 550m for 1000Base- SX transceivers. I would really apreciate feedback from HPE just to validate this.


    Cjoseph, I also agree with you: "If you do it, do it right, do it from the beginning"

     

    Regards

     

     

     



  • 11.  RE: GbE Transceivers

    MVP EXPERT
    Posted Jan 23, 2019 05:30 PM

    Hi N3tw0rk3r,

    I always will try to help you best as i can, it also keep my own knowledge hight as possible ;). From own expercience i only see this conditioning cables in old enviorments (OM1/OM2) and never use them by my own. What i read on wikipedia (always true ;)) but also reference on the cisco guide and hpe matrix (you allready read) is that conditioning cable should not be used at OM3/OM4 enviroments, but why.... i cant found any clue in the IEEE documentation.

     

    Nevermind, best what you can do is open an TAC case for conformation. And please let us known what their advice is.

     



  • 12.  RE: GbE Transceivers

    Posted Jan 30, 2019 10:41 AM

    Hello,

     

    my bet is that the link will come up but if you push too much traffic into it you will get a ton of Rx errors on both ends.

     

    Make sure you buy OM4 MCP (same as the fiber optics already deployed) and connect the single mode end on the reception side of the GBIC. The idea is to "funnel" the light from the multimode fiber (wide core) into the single mode GBIC (narrow core) to avoid reflection.

     

    Cheers,

     

    Aarón