The Cisco GLC-BX-D-120KM (GLC-BX-D-120KM - Cisco 1Gb/s 1000Base-BX-D Single-Mode Fiber 120km 1570nmTX/1550nmRX LC Connector SFP Transceiver Module) is a Transceiver component engineered for sustained enterprise-class workloads. This part addresses common procurement scenarios where exact-match replacement, capacity expansion, or new-build deployment is required. Technical specifications include capacity of 1 GB, data rate of 1 Gb/s, range of 120 km. Common deployment scenarios include data-center ToR (top-of-rack) switching, server-to-storage NAS/SAN connectivity, 10/25/40/100 GbE backbone aggregation, and edge router replacement in branch-office deployments. Pro Disk Network sources the GLC-BX-D-120KM through reputable distribution channels and applies a verification check against the OEM compatibility matrix before each unit is added to active inventory. Each unit ships from a US fulfillment hub (Hillsboro OR, Atlanta GA, or Phoenix AZ) with same-day dispatch on in-stock orders before 3pm ET. 90-day Pro Disk Network functional warranty included; free US ground shipping on orders over $150.
The GLC-BX-D-120KM is a Cisco transceiver component with capacity 1 GB, data rate 1 Gb/s, range 120 km. Pricing on the GLC-BX-D-120KM is quote-based — email sales@prodisknetwork.com or use our live chat for a quote within one business day.
Reviewed By
Reviewed by:Pro Disk Network Engineering Team — . Specifications, compatibility, and pricing for the GLC-BX-D-120KM are shown on this page.
Trust Signals
US-based LLC — 7345 W Sand Lake Rd, STE 210, Office 3208, Orlando, FL 32819
Same-Day US Shipping — orders before 3pm ET ship today via UPS
30-Day Returns — pre-paid label on DOA and defective items
Quick Answer: Is the GLC-BX-D-120KM compatible with my switch?
Pro Disk Network validates every GLC-BX-D-120KM against the target switch's published compatibility matrix before shipment. If you let us know your switch model and firmware version, we will confirm fitment and code the module appropriately (Cisco-coded, Juniper-coded, HPE-coded, etc.) at no extra charge.
How fast does the GLC-BX-D-120KM ship?
GLC-BX-D-120KM orders placed before 3 pm ET ship the same business day from US warehouses. Delivery is next business day to most metro ZIPs via FedEx/UPS overnight; ground delivery covers remaining US in 1-4 business days.
The GLC-BX-D-120KM is deployed by US enterprises, MSPs, government, and education customers across multiple infrastructure scenarios. Below are the most common deployment patterns Pro Disk Network sees in real-world orders.
Server Uplink — 10G/25G server-to-leaf uplink — pair with matching DAC or AOC at the host NIC to avoid optic mismatch.
DCI (Data Center Interconnect) — Inter-DC routing or aggregation. LR4/LR8 transceivers for 10–80 km, ER4 for 40 km, ZR4 for coherent long-haul.
Campus Distribution — Catalyst-class campus distribution between IDF and MDF closets. PoE+ where wireless APs and IP phones share infrastructure.
Branch / Edge — Smaller form-factor switches and routers for branch sites. SD-WAN-compatible or static-VPN-attached as the architecture dictates.
What is the GLC-BX-D-120KM?
The GLC-BX-D-120KM is a Cisco network interface module with capacity 1 GB and data rate 1 Gb/s, manufactured by Cisco. Pro Disk Network ships this part new and certified-refurbished from our US warehouse with same-day dispatch on orders placed before 3 PM ET, backed by a 30-day return guarantee.
Pros & Cons of GLC-BX-D-120KM
Pros
Same-day US shipping cuts deployment downtime
Cons
DAC cables capped at 7 m — use AOC or fibre for longer runs
SR optic vs LR optic confusion — verify before ordering
Refurbished tier optic does not include retail vendor packaging
Frequently Asked Questions about GLC-BX-D-120KM
Is the GLC-BX-D-120KM a genuine Cisco part?
Yes. Pro Disk Network sources every GLC-BX-D-120KM as factory-original Cisco inventory. New units arrive sealed in OEM packaging; refurbished units are pulled from decommissioned Cisco servers, surface-tested, and re-warranted by Pro Disk Network for 90 days.
Is the GLC-BX-D-120KM compatible with my switch?
Pro Disk Network validates every GLC-BX-D-120KM against the target switch's published compatibility matrix before shipment. If you let us know your switch model and firmware version, we will confirm fitment and code the module appropriately (Cisco-coded, Juniper-coded, HPE-coded, etc.) at no extra charge.
How fast does the GLC-BX-D-120KM ship?
GLC-BX-D-120KM orders placed before 3 pm ET ship the same business day from US warehouses. Delivery is next business day to most metro ZIPs via FedEx/UPS overnight; ground delivery covers remaining US in 1-4 business days.
What is the warranty on the GLC-BX-D-120KM?
New GLC-BX-D-120KM units carry the full Cisco manufacturer warranty (typically 1 to 5 years depending on product line). Refurbished and bulk-OEM units include a Pro Disk Network advance-replacement warranty (90 days refurbished). DOA replacement is free within 30 days of receipt.
Do you offer bulk pricing for the GLC-BX-D-120KM?
Email sales@prodisknetwork.com with the quantity and target ship date for a quote within one business day.
GLC-BX-D120 — GLC-BX-D120 - Cisco 1Gbps 1000BASE-BX10-D Downstream Bidirectional Single Fiber with DOM SFP Transceiver Module — $111.42
Pro Disk Network Buyer’s Guide: Transceiver
Optic Coding, Vendor Lock-In, and Multi-Vendor Compatibility
For Cisco IOS, IOS-XE, and NX-OS switches, the GLC-BX-D-120KM works out-of-box if coded for Cisco; for Aruba ArubaOS-CX, code for HPE/Aruba; for Juniper Junos, code for Juniper. Pro Disk Network confirms the target vendor coding at order time and applies it before shipping. Misordered coding can be flashed in the field but the lead time is longer than ordering correctly the first time.
Bandwidth Sizing for Spine-Leaf, EVPN-VXLAN, and Hyperconverged Storage
Document optic types and bandwidth in your network drawings: SR-SR for intra-rack, LR-LR for inter-rack and DCI, ZR4 for long-haul coherent. Mismatched optic-distance ratings is the most common cause of intermittent link errors that look like cable problems but aren't.