This WD NTK591QB delivers Transceiver functionality and is built for 24/7 enterprise duty cycles. Technical specifications include capacity of 1.25 GB, data rate of 25 Gb/s, network speed of 25 GbE, wavelength of 1551 nm, range of 40 km. Workload fit covers VMware NSX overlay networking, Kubernetes pod-to-pod east-west bandwidth, Storage Replica replication, and high-throughput backup network paths between ToR switches and backup targets. Pro Disk Network supplies the NTK591QB to US business buyers. Stocked units ship same-day on in-stock orders placed before 3pm ET. Pro Disk Network applies a 90-day functional warranty. Free US ground shipping on orders over $150; same-day expedited (UPS Next Day Air, FedEx Priority) available at checkout.
The NTK591QB is a WD transceiver component with capacity 1.25 GB, data rate 25 Gb/s, network speed 25 GbE. Pro Disk Network sells the NTK591QB for $367.03 with same-day US shipping and a 30-day return guarantee.
Reviewed By
Reviewed by:Pro Disk Network Engineering Team — . Specifications, compatibility, and pricing for the NTK591QB 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 NTK591QB compatible with my switch?
Pro Disk Network validates every NTK591QB 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 NTK591QB ship?
If in stock, the NTK591QB 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 NTK591QB 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 NTK591QB?
The NTK591QB is a WD network interface module with capacity 1.25 GB and data rate 25 Gb/s, manufactured by WD. 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 NTK591QB
Pros
Matched-pair option for redundant link orders
Cabling and DAC/AOC labels clearly mark optic class
Cons
Third-party optic — some firmware revs require "service unsupported transceiver-type"
Bulk DAC orders may ship LTL on >100-pc reels
Confirm transceiver coding before mixing vendors in the same chassis
Frequently Asked Questions about NTK591QB
Is the NTK591QB a genuine WD part?
Yes. Pro Disk Network sources every NTK591QB as factory-original WD inventory. New units arrive sealed in OEM packaging; refurbished units are pulled from decommissioned WD servers, surface-tested, and re-warranted by Pro Disk Network for 90 days.
Is the NTK591QB compatible with my switch?
Pro Disk Network validates every NTK591QB 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 NTK591QB ship?
If in stock, the NTK591QB 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 NTK591QB?
New NTK591QB units carry the full WD 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 NTK591QB?
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 NTK591QB 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 NTK591QB 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 NTK591QB and the connected NICs support jumbo frames — some older NICs cap at 9000-byte payloads even when jumbo-enabled.