Cisco GLC-LH-SMD
1000BASE-LX/LH SFP transceiver module, MMF/SMF, 1310nm, DOM, Original Cisco
Product Highlights
Extending your Gigabit Ethernet network across a campus or between buildings shouldn't mean compromising on visibility or reliability. The Cisco GLC-LH-SMD is a 1000BASE-LX/LH SFP transceiver module that delivers 1 Gbps connectivity over both single-mode and multimode fiber at a 1310 nm wavelength — with built-in Digital Optical Monitoring (DOM) for real-time diagnostics.
Designed as the DOM-enabled successor to the legacy GLC-LH-SM, this original Cisco SFP supports link spans of up to 10 km on single-mode fiber and up to 550 m on multimode fiber, making it ideal for inter-building backbone connections, data center cross-connects, and campus access-layer uplinks. The dual LC/PC connector and hot-swappable SFP form factor allow seamless integration into any Cisco platform with a standard SFP slot.
With DOM capability, network administrators can monitor optical output power, input power, temperature, laser bias current, and supply voltage directly from the switch CLI or NMS — enabling proactive fault detection before users are impacted. The GLC-LH-SMD is IEEE 802.3z compliant and can be intermixed on a port-by-port basis with other Cisco SFP types including 1000BASE-SX, 1000BASE-ZX, 1000BASE-EX, and 1000BASE-T modules, giving you maximum deployment flexibility.
Features & Benefits
Digital Optical Monitoring (DOM)
The GLC-LH-SMD supports real-time monitoring of critical transceiver parameters including optical TX/RX power, temperature, laser bias current, and supply voltage. This gives network teams the ability to detect fiber degradation or transceiver issues proactively — before they cause outages — reducing mean time to repair and preventing costly downtime.
Dual Fiber-Type Support
This SFP operates on both single-mode fiber (up to 10 km) and multimode fiber (up to 550 m), providing flexibility to leverage your existing fiber plant. When deploying over legacy multimode fiber, a mode-conditioning patch cord is required per the IEEE 802.3z standard to ensure signal integrity.
Hot-Swappable SFP Design
The GLC-LH-SMD is fully hot-swappable, allowing you to install, replace, or upgrade transceivers without powering down the host device. This minimizes maintenance windows and keeps your network available during routine changes — critical in 24/7 enterprise and service-provider environments.
Port-by-Port Flexibility
Cisco SFP modules can be intermixed on a port-by-port basis across 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-EX, 1000BASE-ZX, and 1000BASE-BX types. This "pay as you populate" approach lets you tailor each port to its specific distance and media requirement without committing to a single fiber type across the entire switch.
IEEE 802.3z Compliance
Full compliance with the IEEE 802.3z 1000BASE-LX standard ensures interoperability with standards-based equipment from any vendor. The 1310 nm wavelength and standardized optical parameters guarantee predictable performance across multi-vendor fiber networks.
Deployment Scenarios
Campus Inter-Building Backbone
Connect buildings across a campus with up to 10 km of single-mode fiber at Gigabit speeds. The GLC-LH-SMD's DOM capability lets facilities teams monitor link health across long outdoor fiber runs where environmental factors can degrade performance over time.
Data Center Cross-Connects
Use the GLC-LH-SMD for Gigabit Ethernet interconnects between switches, routers, and firewalls within or between data center rooms. Hot-swappability ensures zero-downtime maintenance, and DOM provides the diagnostics needed to meet strict SLA requirements.
Enterprise Access-Layer Uplinks
Deploy in Catalyst access-layer switches to provide fiber uplinks to distribution or core switches. The ability to operate on both MMF and SMF means you can use the same SFP part number regardless of the fiber type installed in each wiring closet.
Service Provider CPE Connectivity
Ideal for managed Ethernet services where the provider needs to deliver 1 Gbps handoffs at customer premises. DOM support enables remote monitoring of the optical link from the NOC, reducing the need for costly truck rolls to diagnose fiber issues.
General
Performance
Fiber & Distance
Physical
Environmental
Power
Compliance
Compatibility Notes
The Cisco GLC-LH-SMD is supported across a broad range of Cisco platforms including:
- Catalyst Switches: 2960, 2960-S, 2960-X, 3560, 3560-X, 3650, 3750, 3750-X, 3850, 4500, 4500-X, 6500, 6800 Series
- Routers: ASR 901, ASR 903, ASR 1000, ASR 9000 Series; ISR 2900, 3800 Series
- Security Appliances: ASA 5500 Series
- Industrial: IE 3010 Series
A mode-conditioning patch cord is required when operating over multimode fiber, per IEEE 802.3z. Consult the Cisco SFP Compatibility Matrix for platform-specific minimum IOS/IOS-XE software versions and DOM support details.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| GLC-LH-SM | Cisco 1000BASE-LX/LH SFP (Non-DOM) | Legacy predecessor without DOM support; EOL — GLC-LH-SMD is the direct replacement with added digital diagnostics. |
| SFP-GE-L | Cisco 1000BASE-LX/LH SFP (Extended Temp) | Also supports DOM with an extended operating temperature range of -5°C to 85°C; higher cost than GLC-LH-SMD. |
| GLC-LX-SM-RGD | Cisco 1000BASE-LX/LH Rugged SFP | Industrial-grade rugged SFP with -40°C to 85°C operating range; designed for Cisco industrial Ethernet switches. |
| GLC-SX-MMD | Cisco 1000BASE-SX SFP (DOM) | Short-wavelength 850nm SFP for multimode fiber only; max 550m on OM2 — choose GLC-LH-SMD when you need SMF or longer reach. |
