Cisco GLC-BX-D
1000BASE-BX SFP, 1490NM, Original Cisco
Product Highlights
Fiber cabling is one of the largest capital expenses in any network build. Every strand you can eliminate from a design translates directly into lower material, labor, and pathway costs. The Cisco GLC-BX-D 1000BASE-BX10-D SFP transceiver solves this challenge by enabling full-duplex Gigabit Ethernet over a single strand of standard single-mode fiber (SMF).
Using integrated WDM (Wavelength-Division Multiplexing) technology, the GLC-BX-D transmits at 1490nm and receives at 1310nm, separating upstream and downstream traffic on one fiber. It must be paired with a complementary GLC-BX-U (upstream) transceiver at the remote end. Together, the pair delivers reliable 1 Gbps connectivity over distances up to 10 kilometers — making it an excellent fit for campus backbones, inter-building links, and metro-access deployments where fiber count is limited or expensive to expand.
As a genuine Cisco SFP, the GLC-BX-D supports Digital Optical Monitoring (DOM) per SFF-8472, giving network teams real-time insight into optical power levels, temperature, laser bias current, and supply voltage. The hot-swappable design allows field replacement without service interruption, and the module is compatible with a broad range of Cisco Catalyst switches, ISR routers, and other platforms that accept standard SFP transceivers.
Features & Benefits
Single-Fiber Bidirectional (BiDi) Technology
The GLC-BX-D integrates a WDM splitter directly inside the SFP module, separating 1490nm transmit and 1310nm receive wavelengths onto a single fiber strand. This cuts fiber cabling requirements in half compared to traditional dual-fiber SFPs — reducing material costs, simplifying cable management, and making the most of limited fiber plant in existing conduit or duct infrastructure.
Digital Optical Monitoring (DOM)
Built-in DOM (SFF-8472 compliant) provides real-time monitoring of five critical parameters: optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage. This enables proactive fault detection, faster troubleshooting, and data-driven lifecycle management — reducing mean time to repair and preventing unexpected outages.
10km Single-Mode Fiber Reach
With a maximum operating distance of 10 kilometers over standard G.652 single-mode fiber, the GLC-BX-D is purpose-built for campus backbone, inter-building, and metro-access applications. It bridges the gap between short-reach multimode optics and costly long-haul solutions, delivering the right reach at the right price point.
Hot-Swappable SFP Form Factor
The industry-standard SFP (Small Form-Factor Pluggable) design allows the GLC-BX-D to be installed or replaced without powering down the host switch or router. This simplifies upgrades, accelerates maintenance windows, and supports mixed-media deployments where different SFP types coexist on a port-by-port basis.
IEEE 802.3ah Standards Compliance
Full compliance with the IEEE 802.3ah 1000BASE-BX10-D standard ensures interoperability with any standards-based 1000BASE-BX10-U device on the remote end. This protects your investment and provides flexibility as your network evolves.
Deployment Scenarios
Campus Backbone & Inter-Building Links
Connect buildings across a campus using a single strand of SMF per link. The GLC-BX-D paired with a GLC-BX-U at the remote end delivers 1 Gbps full-duplex connectivity up to 10km, maximizing the capacity of existing fiber plant without pulling new cable.
Metro-Access & Service Provider Edge
Service providers and enterprises deploying fiber-to-the-building or metro Ethernet services can leverage BiDi SFPs to double the subscriber density on existing fiber infrastructure. Each customer link requires only one fiber strand instead of two, significantly reducing per-port fiber costs.
Fiber-Constrained Environments
In older facilities or congested conduit pathways where available fiber strands are limited, the GLC-BX-D enables Gigabit Ethernet connectivity without the expense and disruption of new fiber installation. Pair it with a GLC-BX-U to reclaim strands for additional links or future growth.
Redundant Uplink Deployments
Use BiDi SFPs to create redundant uplinks between access and distribution layer switches while consuming fewer fiber strands. This frees up fiber capacity for out-of-band management, security cameras, or future 10G upgrades.
General
Performance
Optical
Connector & Fiber
Physical
Environmental
Compliance & Standards
Compatibility Notes
Pairing Requirement: The GLC-BX-D (downstream, 1490nm TX / 1310nm RX) must be paired with a GLC-BX-U (upstream, 1310nm TX / 1490nm RX) at the opposite end of the fiber link. Two GLC-BX-D modules cannot be connected to each other.
Compatible Platforms: The GLC-BX-D is supported across a wide range of Cisco platforms with SFP slots, including Catalyst 2960, 2960-S, 2960-X, 3560-X, 3750, 3750-X, 3650, and 3850 series switches, as well as ISR routers such as the 2900 and 3900 series. Always verify compatibility with the Cisco Transceiver Module Group (TMG) Compatibility Matrix for your specific platform and IOS version.
Fiber Type: Standard single-mode fiber (ITU-T G.652) with a simplex LC/PC connector.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| GLC-BX-U | Cisco 1000BASE-BX10-U SFP (Upstream) | Required pairing partner — transmits at 1310nm and receives at 1490nm (opposite wavelengths to GLC-BX-D) |
| GLC-BX-D-I | Cisco 1000BASE-BX10-D SFP (Industrial Temp) | Same BiDi downstream functionality but rated for industrial temperature range (-40°C to 85°C) |
| GLC-LH-SMD | Cisco 1000BASE-LX/LH SFP | Traditional dual-fiber 1000BASE-LX SFP — uses two fiber strands (TX + RX) instead of one; 1310nm wavelength, 10km reach |
| GLC-2BX-D | Cisco 2-Channel 1000BASE-BX10-D Compact SFP | Integrates two 1000BASE-BX10-D interfaces in a single SFP module for FTTx deployments — doubles port density per SFP slot |
