Cisco GLC-BX-U
1000BASE-BX SFP, 1310NM, Original Cisco
Product Highlights
Fiber cabling is one of the largest capital expenses in any network build-out. Every strand you can eliminate translates directly into savings on materials, labor, and pathway capacity. The Cisco GLC-BX-U is a 1000BASE-BX bidirectional (BiDi) SFP transceiver that solves this problem by enabling full-duplex Gigabit Ethernet over a single strand of standard single-mode fiber.
Using Wavelength-Division Multiplexing (WDM) technology, the GLC-BX-U transmits at 1310nm and receives at 1490nm through a single simplex LC connector. It must be paired with a complementary GLC-BX-D transceiver at the remote end, which transmits at 1490nm and receives at 1310nm. Together, the pair delivers 1 Gbps connectivity over distances up to 10 km — ideal for campus backbones, inter-building links, and metro-access deployments where fiber count is limited or expensive to expand.
This original Cisco transceiver supports Digital Optical Monitoring (DOM) per the SFF-8472 MSA, giving network engineers real-time visibility into optical power levels, temperature, laser bias current, and supply voltage. The hot-swappable SFP form factor plugs into any compatible Cisco Gigabit Ethernet port, and it can be intermixed on a port-by-port basis with other Cisco SFP types including 1000BASE-SX, 1000BASE-LX/LH, and 1000BASE-T modules.
Features & Benefits
Single-Fiber Bidirectional Technology
The GLC-BX-U uses integrated WDM optics to separate transmit (1310nm) and receive (1490nm) wavelengths on a single fiber strand. This effectively halves your fiber requirement compared to traditional dual-fiber SFPs, freeing up conduit capacity and reducing cabling costs — especially valuable in buildings where pulling new fiber is impractical or prohibitively expensive.
Digital Optical Monitoring (DOM)
Built-in DOM support compliant with the SFF-8472 MSA lets you monitor critical parameters — optical output power, received signal strength, module temperature, laser bias current, and supply voltage — directly from your switch or router CLI. Proactive monitoring means you can identify degrading links before they cause outages.
Hot-Swappable & Flexible Deployment
The SFP form factor is hot-swappable, so you can insert or remove the transceiver without disrupting other ports or powering down the device. Cisco's port-by-port media flexibility means you can mix GLC-BX-U modules alongside 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-T, and other SFP types in the same chassis — a true pay-as-you-populate model.
Standards-Based Interoperability
Compliant with IEEE 802.3ah 1000BASE-BX10-U, the GLC-BX-U operates on standard single-mode fiber (ITU-T G.652) and uses an industry-standard simplex LC connector. This ensures reliable, predictable performance across your existing fiber plant with no special cabling requirements.
Deployment Scenarios
Campus Inter-Building Links
Connect multiple buildings across a campus using a single fiber strand per link instead of two. The GLC-BX-U's 10km reach covers most campus distances, and the fiber savings compound quickly across dozens of links.
Metro-Access & Service Provider Edge
Service providers delivering Gigabit Ethernet handoffs to business customers can maximize the capacity of existing fiber plant by deploying BiDi SFPs. Each customer link requires only one fiber instead of two, effectively doubling the subscriber density on a given fiber bundle.
Fiber-Constrained Environments
In older buildings or congested conduit paths where available fiber strands are limited, the GLC-BX-U lets you establish Gigabit links without pulling new cable. This is especially valuable in retrofit or brownfield deployments where construction is costly or disruptive.
Branch Office & Remote Site Connectivity
For organizations connecting branch offices or remote facilities back to a central hub over leased dark fiber, BiDi SFPs reduce the number of fiber strands required per link — lowering recurring lease costs and simplifying cable management.
General
Optical Characteristics
Performance
Environmental
Pairing Requirements
Compatibility Notes
- Required Pairing: The GLC-BX-U (upstream, 1310nm TX / 1490nm RX) must always be paired with a GLC-BX-D (downstream, 1490nm TX / 1310nm RX) at the opposite end of the fiber link.
- Fiber Type: Single-mode fiber (SMF), ITU-T G.652 compliant.
- Connector: Simplex LC/PC.
- Compatible Platforms: Designed for use in Cisco switches and routers with SFP Gigabit Ethernet ports. Can be intermixed port-by-port with other Cisco GE SFP modules (1000BASE-SX, 1000BASE-LX/LH, 1000BASE-T, 1000BASE-EX, 1000BASE-ZX).
- Industrial Variant: For extended temperature environments (-40°C to 85°C), see the GLC-BX-U-I.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| GLC-BX-D | Cisco 1000BASE-BX10-D SFP (Downstream) | Complementary downstream pair — transmits at 1490nm and receives at 1310nm. Required at the remote end of every GLC-BX-U link. |
| GLC-BX-U-I | Cisco 1000BASE-BX10-U SFP (Industrial Temp) | Same BiDi optics as GLC-BX-U but rated for industrial temperature range (-40°C to 85°C) for harsh environments. |
| GLC-LH-SMD | Cisco 1000BASE-LX/LH SFP | Traditional dual-fiber 1000BASE-LX/LH SFP for 10km over SMF. Requires two fiber strands but does not need a paired transceiver type. |
| GLC-SX-MMD | Cisco 1000BASE-SX SFP | Short-reach 1000BASE-SX SFP for multimode fiber up to 550m. Lower cost for short in-building links where single-mode fiber is not available. |
