Sourced for enterprise IT teams managing Cisco UCS C-Series and B-Series blade chassis, plus Catalyst and Nexus switching platforms, the Cisco GLC-LH-SM-20 (GLC-LH-SM-20 - Cisco 1Gbps 1000Base-LX/LH Single-Mode Fiber 20km 1310nm Duplex LC Connector SFP Transceiver Module) is a Networking Devices component matched to OEM specifications. Each unit is verified against manufacturer datasheet revisions and is appropriate for new-build, expansion, or warranty-replacement procurement. Technical specifications include wavelength of 1310 nm, range of 20 km. Appropriate for enterprise core-aggregation tier, hyperscale leaf-spine fabric expansion, EVE-NG / GNS3 lab environments at scale, and matched-pair high-availability switching deployments. Our procurement team maintains active inventory of the GLC-LH-SM-20 and verifies condition, firmware revision, and OEM part-number registry alignment for each unit prior to sale. Stocked units ship same-day on in-stock orders placed before 3pm ET. Pro Disk Network applies a 30-day functional warranty and accepts Net 30 / Net 60 terms for qualified business accounts. Free US ground shipping on orders over $150; same-day expedited (UPS Next Day Air, FedEx Priority) available at checkout.
The GLC-LH-SM-20 is a Cisco networking devices component with wavelength 1310 nm, range 20 km. Pro Disk Network sells the GLC-LH-SM-20 for $77.51 with same-day US shipping and a 30-day free return guarantee.
Reviewed By
Reviewed by:Pro Disk Network Engineering Team — . Specifications, compatibility, and pricing for the GLC-LH-SM-20 verified against the manufacturer datasheet and our internal lab benchmarks.
Quick Answer: Is the GLC-LH-SM-20 compatible with my switch?
Pro Disk Network validates every GLC-LH-SM-20 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-LH-SM-20 ship?
Pro Disk Network dispatches the GLC-LH-SM-20 same-day on orders confirmed before 2 pm ET. Multi-pallet projects requiring crating ship within 2 business days. International shipping (Canada, Mexico, EU, APAC) takes 3-7 business days via DHL Express or FedEx International Priority.
The GLC-LH-SM-20 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.
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.
New, Bulk, or Refurbished — Choosing Your Tier
Pro Disk Network offers the GLC-LH-SM-20 across three procurement tiers. Each tier is fully functional and warranted; the choice comes down to budget, warranty length, and whether the deployment is production-critical or capacity-expansion.
Tier
Discount vs OEM List
Warranty
Best For
New (Sealed OEM)
25–40%
Cisco manufacturer warranty (1–5 yr)
Production-critical first-tier
New (Bulk OEM)
50–65%
3-year Pro Disk Network warranty
New cluster builds, secondary tier
Refurbished
75–85%
12-month advance replacement
Capacity expansion, lab, dev/test, EOL refresh
Bulk & Volume Pricing for GLC-LH-SM-20
Ships from our US warehouse — same-day US dispatch on orders placed before 2pm ET. Net 30 terms available for verified businesses, government and education.
Volume discounts on the GLC-LH-SM-20 are automatic at checkout. Net 30 terms available for verified businesses, government, and education. Email sales@prodisknetwork.com for orders above 100 units.
Quantity
Discount
Unit Price
1
0%
$77.51
5+
4%
$74.41
10+
8%
$71.31
25+
13%
$67.43
50+
18%
$63.56
100+
23%
$59.68
What is the GLC-LH-SM-20?
The GLC-LH-SM-20 is a Cisco enterprise networking device with wavelength 1310 nm and range 20 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 GLC-LH-SM-20
Pros
Verified compatibility with leaf-spine and EOR/MOR topologies
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 GLC-LH-SM-20
Is the GLC-LH-SM-20 a genuine Cisco part?
Yes. Pro Disk Network sources every GLC-LH-SM-20 as factory-original Cisco inventory verified against the manufacturer parts registry before listing. 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 12 months.
Is the GLC-LH-SM-20 compatible with my switch?
Pro Disk Network validates every GLC-LH-SM-20 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-LH-SM-20 ship?
Pro Disk Network dispatches the GLC-LH-SM-20 same-day on orders confirmed before 2 pm ET. Multi-pallet projects requiring crating ship within 2 business days. International shipping (Canada, Mexico, EU, APAC) takes 3-7 business days via DHL Express or FedEx International Priority.
What is the warranty on the GLC-LH-SM-20?
New GLC-LH-SM-20 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 (12 months refurbished, 36 months new bulk). DOA replacement is free within 30 days of receipt.
Do you offer bulk pricing for the GLC-LH-SM-20?
Yes. Pro Disk Network offers automatic volume discounts at 10, 25, 50, and 100+ unit tiers. Net 30 terms are available for verified businesses, government, and education buyers. Email sales@prodisknetwork.com with the quantity and target ship date for a quote within one business day.
Pro Disk Network Buyer’s Guide: Networking Devices
Optic Coding, Vendor Lock-In, and Multi-Vendor Compatibility
If you are running a multi-vendor leaf-spine architecture (Arista leaves and Cisco spines, for example), order optics coded for each endpoint separately. Optics in DAC and AOC cables are factory-coded to each end and cannot be flashed in-field. Plan the coding split at design time and document it in your network drawings.
Bandwidth Sizing for Spine-Leaf, EVPN-VXLAN, and Hyperconverged Storage
Sizing network bandwidth for a leaf-spine fabric using the GLC-LH-SM-20 starts with the workload mix. For general-purpose virtualisation, plan 10G server-to-leaf, 25G or 40G leaf-to-spine; oversubscription up to 4:1 is acceptable. For hyperconverged storage (vSAN, Ceph, Storage Spaces Direct), plan 25G server-to-leaf at minimum, 100G leaf-to-spine, oversubscription 1.5:1 maximum. East-west traffic dominates in HCI clusters and starves on oversubscribed fabrics.