Cisco C9300L-24UXG2Q-10E: What Does It Offer,
Defining the C9300L-24UXG2Q-10E The Cisco C9300L-...
GLC-ZX-SMD= Overview: Long-Haul Gigabit Connectivity
The Cisco GLC-ZX-SMD= is a 1000BASE-ZX SFP transceiver engineered for single-mode fiber (SMF) deployments requiring extended reach. Operating at 1550nm wavelength, it achieves 70km to 80km distances with 9/125µm fiber, making it a go-to solution for metro Ethernet, cross-campus links, and service provider backhauls.
Technical Specifications and Differentiation
- Data Rate: 1Gbps (Gigabit Ethernet)
- Reach: 70km (GLC-ZX-SM) vs 80km (GLC-ZX-SMD=) due to enhanced receiver sensitivity
- Fiber Type: Single-mode only (incompatible with OM3/OM4 multimode)
- DOM Support: Real-time monitoring of TX power, RX power, voltage, and temperature (critical for carrier-grade SLAs)
- Power Consumption: 1W max, compliant with IEEE 802.3ae
Key Use Cases and Deployment Scenarios
1. Metro Ethernet Aggregation
Telecom providers use this SFP to connect central offices to edge POPs without deploying DWDM gear. Its 80km reach eliminates intermediate regeneration sites.
2. Campus Disaster Recovery Links
Enterprises with geographically dispersed data centers (e.g., university systems) leverage it for asynchronous replication of non-latency-sensitive workloads.
Addressing Critical User Questions
Q: Can GLC-ZX-SMD= achieve 100km with amplification?
No. The built-in laser is Class 1M, capped at 80km. Exceeding this requires external EDFA amplifiers and dispersion-compensating modules, which Cisco doesn’t validate.
Q: Is it compatible with Nexus 3548 switches?
Yes, but only in non-QSFP breakout configurations. Inserting it into a 40G breakout port (e.g., Nexus 40G-QSFP-to-4x10G) triggers unsupported transceiver errors.
Installation and Optimization Best Practices
- Optical Attenuation Management: For links <25km, install 5-10dB attenuators to prevent receiver saturation.
- Firmware Compliance: On Catalyst 3850 switches, ensure IOS-XE 16.6.4+ to avoid DOM readout glitches.
For enterprises requiring Cisco-authenticated modules, the GLC-ZX-SMD= is purchasable here, though availability fluctuates with regional stock.
Common Pitfalls and Troubleshooting
1. Intermittent CRC Errors on Long Links
Caused by chromatic dispersion in older SMF-28e fiber. Replace with SMF-28 Ultra or enable FEC (Forward Error Correction) on supported platforms:
interface GigabitEthernet0/1
fec encoding rs 2. Mismatched Wavelengths in Bidi Scenarios
The 1550nm GLC-ZX-SMD= cannot pair with 1310nm Bidi SFPs. Use DWDM multiplexers for hybrid wavelength topologies.
Cost vs. Performance: Is This SFP Still Relevant in 2024?
Having deployed these in subsea cable landing stations, the GLC-ZX-SMD= remains indispensable for legacy 1Gbps SMF infrastructure where upgrading to 10G/100G isn’t fiscally viable. However, in greenfield projects, QSFPDD-400G-ZR-S coherent optics offer 10x the bandwidth at comparable per-km costs. For municipal networks or utilities with sunk investments in 1G core switches, though, this transceiver delivers reliable, carrier-hardened performance without overhauling existing gear.