Connection using GLC-BX

[Matthew Loggan]

Hi,

I would like to know if the following connection is correct for communicate two site using a SMF (Single Strand):

Catalyst 3850 -> GLC-BX-D ----> Single Strand of SMF <---- GLC-BX-U-> Catalyst 3850

One GLC-BX-D in one side of the link and one GLC-BX-U in the other side? that is correct?

I already have checked the compatibility of both transceivers with the C3850-NM-4-1G

Best Regards.

[fiberstorejames]

To tell the truth, GLC-BX-D and GLC-BX-U transceivers both work with single-mode fiber but they operate at different wavelength, so it might cause error. The above links are  for your reference ! 

[Tom Randstrom]

Below is taken from the Cisco SFP Modules for Gigabit Ethernet Applications Data Sheet:

1000BASE-BX10-D and 1000BASE-BX10-U SFP for Single-Fiber Bidirectional Applications

The 1000BASE-BX-D and 1000BASE-BX-U SFPs, compatible with the IEEE 802.3ah 1000BASE-BX10-D and 1000BASE-BX10-U standards, operate on a single strand of standard SMF.

A 1000BASE-BX10-D device is always connected to a 1000BASE-BX10-U device with a single strand of standard SMF with an operating transmission range up to 10 km.

The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices as depicted in Figure 2: 1000BASE-BX10-D transmits a 1490-nm channel and receives a 1310-nm signal, whereas 1000BASE-BX10-U transmits at a 1310-nm wavelength and receives a 1490-nm signal. As shown, the presence of a wavelength-division multiplexing (WDM) splitter integrated into the SFP to split the 1310-nm and 1490-nm light paths.

Figure 4.      Bidirectional Transmission of a Single Strand of SMF

[DPAR]

Your connection is absolutely correct!

You required the different tx/rx transmissions provided by your "D" and "U" SPFs in order to properly communicate across a single fiber.  A very common mistake is to use the same type of SFP on a single (BiDi - BiDirectional) fiber.

[Jahirul]

Hi,

I want to established a connection between GLC-BX-D= to GLC-BX-D= SFP module. Will it work??

As both of the transceiver have same wavelength 1490NM. Please help me for this.

[Carl Lindahl]

No, that will not work due to the internal filter in the SFP. You need to
have a BX-U on one end and a BX-D on the other end of the fiber for this to
work.

[Jahirul]

Hi,

If I want to established a connection between SFP-10G-BXD-I= to SFP-10G-BXD-I=SFP module. Will it work??

Please help me for this.

[DPAR]

No, this won't work.



A Bidirectional (BiDi) SFP uses a single strand (simplex) fiber. The SFP
uses two different channels (wavelengths) in order to transmit (Tx) and
receive (Rx) data. An SFP-10G-BXD-I must be used with a SFP-10G-BXU-I. Pay
special attention to the naming convention. Notice the "D" (Downstream) and
"U" (Upstream). Every BiDi SFP must be used with it's appropriate pair. If
you were to look at a spec sheet; you'd see that the SFP-10G-BXD is using
1330nm-TX/1270nm-RX and the SFP-10G-BXU is using 1270nm-TX/1330nm-RX. Since
one SFP's Tx speaks to the other's Rx I hope you can see why you are
required to use D /U in pairs across a fiber.