We use a Cisco SG300 for small routing issues in one Part of our Network, now we want to create a cross connect between two locations. Between both Location we use a dark fibre from a provider. On the one side we want to connect the Darkfibre on one SFP Port of the SG300 (with Cisco MGBLX1 Gigabit Ethernet LX Mini-GBIC SFP Transceiver) and on the other side we want connect to the SFP+ Port of the ISR 2921 (with 1000BASE-LX/LH SFP transceiver module, MMF/SMF, 1310nm, DOM) and provide a Network access over the Ethernet Port of the ISR 2921.

We want connect two networks over this cross connect. Are there some problems with or is this applicable? The Darkfibre distance between both Locations are about 4km, and we realize only a few VoIP Channels over this connection.

Is the GLC-LH-SMD= compatible with the MGBLX1?

2 Answers 2


You need to look at the standard for each. The MGBLX1 and the GLC-LH-SMD both have support for 1000BASE-LX.

What you really need to do is make sure that these are compatible with the fiber which you are using. You can contact you provider to verify this.

  • The provider told me that is single mode, any other things we need to know? For a test environment I had order a Singlemode Fibre with duplex LC/LC connector.
    – kockiren
    Feb 18, 2016 at 6:55

MGBLX1 is the 1000BASE-LX SFP transceiver, designed for SMF with 1310nm wavelength, and GLC-LH-SMD is 1000BASE-LX/LH SFP transceiver for both MMF and SMF, also 1300-nm wavelength, with DOM support, dual LC/PC connector. It's obvious that these two modules are compatible. It seems that you can go on your project for sure.

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