Cisco optic part numbers pack a lot of information into a short code. Once you know the pattern, you can tell the form factor, speed and reach at a glance, and you can avoid ordering the wrong variant.

The pattern

Most Cisco transceiver part numbers follow this shape:

FORMFACTOR-SPEED-STANDARD[-VARIANT][=]

Example: SFP-10G-LR-S=

Part Meaning
SFP Form factor: SFP or SFP+ cage
10G Data rate: 10 Gb/s
LR Optical standard: 10GBASE-LR, 1310 nm, 10 km on single-mode fibre
S Variant: "S-class" (see below)
= Spare: sold as a separate, individually packaged part

Common prefixes

  • GLC-: 1G SFP modules, for example GLC-SX-MMD= and GLC-LH-SMD=
  • SFP-10G-: 10G SFP+ modules
  • SFP-25G-: 25G SFP28 modules
  • QSFP-40G-: 40G QSFP+ modules
  • QSFP-100G-: 100G QSFP28 modules
  • QDD-400G-: 400G QSFP-DD modules
  • SFP-H10GB- / QSFP-H40G-: passive copper DAC cables, for example SFP-H10GB-CU3M= (10G, 3 m)
  • -AOC: active optical cables, for example QSFP-100G-AOC5M=

What the standard tells you

  • SR: short reach, multimode fibre, 850 nm
  • LR / LH: long reach, single-mode fibre, 1310 nm, about 10 km
  • ER / EX: extended reach, single-mode, about 40 km
  • ZR / ZX: about 70 to 80 km on single-mode
  • BX-U / BX-D: BiDi, one fibre strand, sold as an upstream and downstream pair
  • T: copper, RJ-45
  • CUnM: copper DAC, n metres long

Suffixes that matter

  • -MMD / -SMD: multimode or single-mode, with Digital optical monitoring (DOM)
  • -S: Cisco's "S-class" optics, aimed at data-centre and enterprise use, with the standard commercial temperature range
  • -I: industrial temperature range (−40 to 85 °C)
  • -E: extended temperature range
  • -RGD: ruggedised, for industrial switches

Why the "=" matters

The trailing = marks a spare part. It means the module is ordered on its own, in its own sealed packaging, rather than shipped pre-installed or bundled with a chassis.

  • SFP-10G-SR-S without = usually appears on configuration quotes, as a part bundled with a switch.
  • SFP-10G-SR-S= is the stand-alone spare you buy to stock or to add to an existing switch.
  • The hardware inside is the same; the difference is how it is packaged and sold.

Because the = is easy to drop when copying part numbers, our search treats SFP-10G-SR-S, SFP-10G-SR-S= and sfp10gsrs as the same part. Paste whichever version you have.

Check before ordering

  1. Confirm the platform supports the exact part number. For example, an -S optic is supported on most current Catalyst and Nexus platforms, but check Cisco's compatibility matrix for your model and software release.
  2. Match the far end. Both ends of a link must use the same standard (LR to LR, SR to SR).
  3. Check the fibre: multimode for SR, single-mode for LR, ER and ZR.
  4. Check the temperature rating if the switch is in an unconditioned cabinet or outdoors.

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