XFP and QSFP28 Supplier Guide

Sourcing XFP and QSFP28 modules together is a common requirement, because many networks run both: legacy 10G equipment with XFP slots alongside current 100G equipment with QSFP28 ports. A supplier that covers both families simplifies that sourcing, because the buyer can confirm compatibility, spares and support in one conversation rather than two. This guide covers what to check when sourcing the two families together.

The first check is the slot question, which is settled by the equipment. XFP slots take XFP modules; QSFP28 ports take QSFP28 modules; neither takes the other. A buyer sourcing both families should list the equipment at each end of every link, so the format for each link is settled before any model is chosen. The XFP versus SFP+ guide and the QSFP28 versus QSFP guide on this site explain the format differences, and the series pages list the titles available in each family.

The second check is the fiber question, which is settled by the plant. XFP links in legacy equipment are often single-mode, because legacy 10G links often run between buildings or sites, while QSFP28 links in a data centre are often multimode at short reach or single-mode at longer reach, depending on the variant. A buyer should state the fiber type and the distance for each link, not just the speed, because speed alone does not determine the module.

The third check is availability, and it runs differently for the two families. QSFP28 modules are current products, produced in volume, and availability is usually a matter of lead time. XFP modules are maintenance products, produced in smaller volumes for an installed base, and availability is the first question: a title that cannot be supplied is no use at any price. A buyer sourcing both families should ask about availability for the XFP titles first, because that is where a sourcing plan most often fails.

The fourth check is the same as for any supplier: published specifications for the models with specification sheets, series-level honesty for the titles without them, certificates available upon request, and straight answers about gaps. On this site, the fully specified XFP model is the XFP LR and the fully specified QSFP28 model is the QSFP28 LR4, each on its own detail page. Before ordering, confirm quantity, price and delivery time during the inquiry. Certificates are available upon request.