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New Member

1000 Base BX Over 10KM

I have seen several vendors on the internet that manufacture a 1550/1310 transceiver for 1000 Base BX U/D operation over a single mode fiber strand. According to the documentation that i have found on Cisco's site, it appears that the max distance is 10km.

Is it possible to stretch Cisco operation of 1000 Base BX 1310/1490 to over 10km? What are my options for 10km + - is 1000BaseZX the only option I have for 3750 series at 10km+

New Member

Re: 1000 Base BX Over 10KM

Over time the laser will degenerate. Cisco certifies their optics to work up to 10km.

I have definately used it in places over 10km, but we have spares in place. I havent gone much further than 10km, and have since moved to another vendor who can do up to 120km over the BX-U/D type SFP.

My average launch power on the BXU is

-6.2dbm and the receiver sensitivity is

-19dbm. This gives you a 12.8 optical budget to work with.

Example, 40,000 feet = 12.191km. At .35 db/km loss that gives you 4.27db used. Add your patch panels (.5db loss), add a reserve in of 3db for bad splices (or whatever), and you should have a sensitivity left over of 4.5dbm, with 8.3dbm used.

Just an example, at 70,000 feet or 21km, I have a estimated reserve sensitivity of 1.3db based off the average launch powers I see when I used those in the past.

New Member

Re: 1000 Base BX Over 10KM

Is there a particular resource that you recommend to learn more about the math and how to properly calculate this kind of stuff? Maybe a whitepaper or book that you reference?

Thanks in advance


Re: 1000 Base BX Over 10KM

if you see this link optical transmit power is -3 to -9 and receive -3 to -19.5dBm, if you get the best combination like -3dBm transmit and -19.5dBm receive then i you can go few more Kilometer.

If your distance is much more than 10Km then ONLY option is Zx but you need 2 fiber not 1 like Bx.

To calculate how far you can go just fill the values in the calculator on this link,

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