Cisco part number GLCBXU120AO identifies the GLCBXU120AO - Addonics 1Gbps 1000Base-BX Single-mode Fibre 120km 1490nmTx/1550nmRx DOM LC Connector SFP Transceiver Module, an enterprise-grade Transceiver unit appropriate for data-center, server-room, and workstation deployment. Technical specifications include range of 120 km. Typical use cases include enterprise LAN core-distribution-access architecture, hyperconverged cluster east-west traffic, SAN fabric uplinks, and replacement of EOL/EOSL networking infrastructure under existing OEM warranty contracts. Pro Disk Network maintains the GLCBXU120AO in our enterprise inventory and verifies each unit against manufacturer datasheet specifications prior to listing. New stock ships factory-sealed where available; refurbished units are tested under load before dispatch and ship with a 90-day Pro Disk Network functional warranty. Same-day dispatch on in-stock orders placed before 3pm ET; free standard ground shipping on US orders over $150.
The GLCBXU120AO is a Cisco transceiver component with range 120 km. Pro Disk Network sells the GLCBXU120AO for $1,384.78 with same-day US shipping and a 30-day return guarantee.
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Reviewed by:Pro Disk Network Engineering Team — . Specifications, compatibility, and pricing for the GLCBXU120AO are shown on this page.
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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 GLCBXU120AO compatible with my switch?
Pro Disk Network validates every GLCBXU120AO 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 GLCBXU120AO ship?
If in stock, the GLCBXU120AO ships same business day on US orders placed before 3 pm ET. Most US ZIP codes receive next-business-day or 2-day delivery via FedEx/UPS Ground or Express. Bulk and project orders shipping in pallets are typically dispatched within 24-48 hours.
The GLCBXU120AO 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.
Spine-Leaf Fabric — Top-of-rack 25G/100G aggregation between leaf and spine switches. Match speed and form factor across both endpoints.
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.
What is the GLCBXU120AO?
The GLCBXU120AO is a Cisco network interface module with range 120 km, 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 GLCBXU120AO
Pros
Matched-pair option for redundant link orders
Cabling and DAC/AOC labels clearly mark optic class
Cons
Not for hyperscale ZR coherent — different SKU family
Some vendors deprecate firmware on EOL part numbers
Mismatched optic+switch firmware can require manual override
Frequently Asked Questions about GLCBXU120AO
Is the GLCBXU120AO a genuine Cisco part?
Yes. Pro Disk Network sources every GLCBXU120AO 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 GLCBXU120AO compatible with my switch?
Pro Disk Network validates every GLCBXU120AO 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 GLCBXU120AO ship?
If in stock, the GLCBXU120AO ships same business day on US orders placed before 3 pm ET. Most US ZIP codes receive next-business-day or 2-day delivery via FedEx/UPS Ground or Express. Bulk and project orders shipping in pallets are typically dispatched within 24-48 hours.
What is the warranty on the GLCBXU120AO?
New GLCBXU120AO 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 GLCBXU120AO?
Email sales@prodisknetwork.com with the quantity and target ship date for a quote within one business day.
Optic Coding, Vendor Lock-In, and Multi-Vendor Compatibility
Networking optics — SFP, SFP+, QSFP+, QSFP28 — are physically interoperable across vendors but logically restricted by firmware coding. The GLCBXU120AO is coded for a specific vendor family at our factory step before shipping, which preserves the OEM warranty workflow and allows the optic to be recognised without ‘service unsupported-transceiver’ CLI overrides. Mixing third-party optics with same-vendor optics in the same chassis is safe; mixing across vendor codings sometimes triggers warnings in the switch log.
Bandwidth Sizing for Spine-Leaf, EVPN-VXLAN, and Hyperconverged Storage
For EVPN-VXLAN overlays, the GLCBXU120AO carries the underlay tunnels in addition to the workload traffic. Plan for VXLAN encapsulation overhead (50 bytes) plus MTU headroom; set the underlay MTU to 9216 (jumbo frames) and the overlay MTU to 9000. Make sure both the GLCBXU120AO and the connected NICs support jumbo frames — some older NICs cap at 9000-byte payloads even when jumbo-enabled.