Cisco GLC-BX80-D-I= Bidi SFP Transceiver: Key Features, Distance Capacity, and Compatibility Demystified

​​GLC-BX80-D-I= Overview: Single-Fiber Bidirectional Connectivity​​

The ​​Cisco GLC-BX80-D-I=​​ is a ​​1Gbps bidirectional (Bidi) SFP transceiver​​ designed for single-strand single-mode fiber (SMF) deployments. It operates on ​​1490nm TX/1310nm RX wavelengths​​, enabling full-duplex communication over a single fiber strand. This module supports ​​80km reach​​ and is engineered for environments requiring cost-efficient long-haul fiber utilization.

​​Technical Specifications Breakdown​​

• ​​Data Rate​​: ​​1.25Gbps​​ (Gigabit Ethernet and Fibre Channel)
• ​​Wavelengths​​: ​​Downstream 1490nm​​, ​​Upstream 1310nm​​ (D = Down direction)
• ​​Fiber Type​​: ​​9/125µm single-mode​​, with ​​APC/UPC connector options​​
• ​​Temperature Range​​: ​​Industrial (-40°C to 85°C)​​, suitable for outdoor deployments
• ​​DOM Support​​: Real-time monitoring of ​​RX power, TX bias, and temperature​​

​​Primary Deployment Scenarios​​

​​1. Service Provider Backhauls​​

The ​​80km reach​​ makes the GLC-BX80-D-I= ideal for connecting cell towers to central offices without needing dual fiber strands. Its ​​industrial temperature tolerance​​ ensures reliability in extreme climates.

​​2. Campus Network Extensions​​

Universities or hospitals with distributed buildings leverage its ​​single-fiber design​​ to reduce cabling costs by 40-50% compared to duplex SFPs.

​​Critical User Questions Addressed​​

​​Q: Does it work with non-Bidi switches like Cisco Catalyst 2960X?​​

Yes, but both ends must use complementary Bidi modules:

• ​​GLC-BX80-D-I= (1490nm TX)​​ pairs with ​​GLC-BX80-U-I= (1310nm TX)​​.
  Mismatched wavelengths or incorrect directional pairing cause ​​RX power faults​​.

​​Q: What’s the difference between GLC-BX80-D and GLC-BX80-D-I=?​​

The ​​”-I=” suffix​​ denotes ​​industrial temperature hardening​​. The standard GLC-BX80-D operates at ​​0°C to 70°C​​, while the “-I=” variant handles ​​-40°C to 85°C​​, critical for 5G node deployments.

​​Installation Best Practices​​

• ​​Optical Budget Management​​: Ensure total link loss (connectors + fiber) stays ​​< 26dB​​ (80km budget). Exceeding this triggers intermittent link drops.
• ​​APC vs UPC Connectors​​: Use ​​APC connectors​​ for links >40km to minimize back reflection.

Organizations prioritizing Cisco-validated modules can source the ​​GLC-BX80-D-I= here​​, though bulk orders may require lead times.

​​Common Compatibility Pitfalls​​

​​1. Nexus 3064 Switch Issues​​

Early NX-OS versions (pre-7.0) lack Bidi SFP auto-sensing. Manually set ​​speed 1000​​ and ​​duplex full​​ via CLI:

interface Ethernet1/1  
 speed 1000  
 duplex full  

​​2. Third-Party OTDR Testing Risks​​

Aggressive OTDR pulses during fiber testing can ​​damage the receiver​​. Always install inline attenuators (5-10dB) before testing.

​​Cost vs Performance: When Does This Transceiver Make Sense?​​

Having deployed these in oilfield SCADA networks, the GLC-BX80-D-I= justifies its premium over standard SFPs only in three scenarios:

1. ​​Single-fiber legacy infrastructure​​ (e.g., old SONET rings being repurposed for LTE backhaul)
2. ​​Industrial environments​​ requiring extended temperature ranges
3. ​​Regions with fiber scarcity​​, where leasing additional strands is cost-prohibited

For urban data centers with abundant fiber, dual-strand SFP-10G-LR offers better future-proofing. However, for remote sites with pre-existing single-mode runs, this module remains unmatched in balancing reach and operational savings.