Cisco Optics SKU Decoder: How to Read Common Ethernet Optics Part Numbers
Quick answer: Read most modern Cisco Ethernet optics product IDs (PIDs) from left to right: family โ speed โ media/reach โ variant. SFP-10G-SR-S, for example, breaks into SFP + 10G + SR + -S. Together, those fields identify an SFP+ module for 10 Gigabit Ethernet, with short-reach multimode optics and an S-Class variant. Always read the complete PID: the same letters can carry different meanings across speed families.
Cisco does not publish a single naming convention that covers every Ethernet optics family. The recurring pattern is a useful way to interpret a PID, but it does not apply uniformly across families.
This guide focuses on the GLC, SFP, QSFP, and QDD Ethernet optics commonly found in enterprise bills of materials (BOMs). Fibre Channel, coherent DWDM, and ONS service-provider products follow different naming systems and are outside this scope. A decoded PID can identify the module design; it cannot establish platform support, minimum software, lifecycle status, or feature parity.
How to Decode SFP-10G-SR-S in Four Parts
Start with one representative PID before using the reference tables:
[SFP] - [10G] - [SR] - [S]
family speed media variant
- SFP โ product family.ย SFP identifies the product family; combined with 10G, it indicates the SFP+ form factor.
- 10G โ Ethernet rate.ย The module supports 10 Gigabit Ethernet.
- SR โ media and reach class.ย In this PID, SR denotes short-reach, 850 nm multimode optics.
- -S โ family-specific variant.ย For this 10G family, Cisco documents -S as the S-Class variant; it doesย notย mean single-mode.
Taken as a whole, SFP-10G-SR-S identifies a 10G SFP+ short-reach multimode module in Cisco’s S-Class range. The exact data-sheet row provides the details the PID does not encode: a duplex LC connector, reach of up to 300 m on OM3 or 400 m on OM4, and the supported feature set.
Hyphens make a PID easier to scan, but they do not always mark separate fields. Some fields include a slash, a lane digit, or multiple letters that must be read together. Older 1G GLC PIDs may also omit the speed.
First determine which of these three PID patterns applies:
- Modern optic:ย The speed is explicit. The speed field may include a slash for dual-rate operation, and the media code may include a lane digit. Examples:ย SFP-10G-SR-S โ [SFP] [10G] [SR] [-S]ย andย QDD-400G-DR4-S โ [QDD] [400G] [DR][4] [-S].
- Legacy 1G optic:ย GLC-SX-MMD โ [GLC] [SX] [MM][D]. Speed is implied and D is embedded in MMD.
- Cable:ย SFP-H10GB-CU3M โ [SFP-H10GB] [CU] [3M]. Read the host interface, cable type, and length.
For an unfamiliar PID, work through four checks:
- What family or form factor does the left-hand block identify?
- Is the speed written in the PID, or implied by an older family such as GLC?
- What does the complete media/reach code mean at that speed?
- Does the final block represent a documented variant, an embedded feature code, or an ordering suffix?
For the four-field pattern, use three passes: read family and speed together, interpret the complete media/reach code, then verify the final field against the documentation for that family.
Check stock, compare options, or talk with our team.
Four Worked Examples Across Different PID Patterns
GLC-SX-MMD: Legacy 1G with Embedded Codes
[GLC] [SX] [MM][D]
family reach fiber + DOM
(1G implied)
- GLC-SX-MMDย belongs to the 1G SFP family; this exact PID has no separate 1G token.
- SXย identifies the 850 nm short-wavelength class.
- MMย confirms multimode fiber.
- The finalย Dย means the module supports digital optical monitoring.
Decoded: This is a 1G multimode SFP with DOM. Its 1 km maximum reach applies only to the supported laser-optimized multimode fiber specified in the data sheet.
SFP-10/25G-LR-S: A Dual-Rate PID
[SFP] - [10/25G] - [LR] - [S]
family two rates reach variant
- 10/25Gย is one speed block and identifies dual-rate operation.
- LRย identifies the 10 km single-mode reach class in this family.
- -Sย is a family-specific variant; it does not mean single-mode.
Decoded: This is a dual-rate 10/25G SFP28 long-reach single-mode optic. The host must still support the exact PID and the required forward error correction (FEC) at 25G.
QSFP-100G-SR4-S: A Lane Digit Inside the Media Code
[QSFP] - [100G] - [SR][4] - [S]
family speed reach + lanes variant
- Together,ย QSFPย andย 100Gย identify the QSFP28 form factor.
- SR4ย is one optical code: short reach over four parallel multimode lanes.
- -Sย is a variant; verify its exact feature set in the data sheet for the 100G family.
Decoded: This is a 100G QSFP28 parallel multimode optic with an MPO-12 interface and a reach of 100 m over OM4. The 4 denotes four optical lanes; it is not a connector code.
QSFP-100G-DR-S vs QDD-400G-DR4-S: Same Letters, Different Architecture
[QSFP] - [100G] - [DR] - [S] = one 100G lane, duplex LC
[QDD] - [400G] - [DR][4] - [S] = four 100G lanes, MPO-12 APC
Both PIDs contain DR, and both identify 500 m single-mode optics. The remaining fields distinguish their architectures:
- QSFP + 100G + DRย identifies one 100G optical lane and a duplex-LC interface.
- QDD + 400G + DR4ย identifies four parallel 100G optical lanes and an MPO-12 APC interface.
- Treat the finalย -Sย as part of each exact PID. Do not assume the 10G S-Class definition applies unless the relevant family data sheet says so.
Design implication: QSFP-100G-DR-S and QDD-400G-DR4-S share a reach class, but they are not interchangeable in a cabling design. Their speed and lane fields identify different optical architectures and connector types.
Prefix and Speed: Identify the Module Generation
The prefix and adjacent speed field work as a pair: together they identify the form factor and module generation.
| PID prefix or pattern | Form factor or role | Speed indication |
|---|---|---|
| Common GLC-SX/LH/EX/ZX/BX examples, SFP-GE- | SFP | 1G is implied in these examples; other GLC PIDs can be 100M or dual-rate |
| SFP-1G- | SFP | 1G is explicit; these modules require a supported 10G-capable or multirate host port |
| SFP-10G- | SFP+ | 10G |
| SFP-25G-, SFP-10/25G- | SFP28 | 25G or dual-rate 10/25G |
| QSFP-40G- | QSFP+ | 40G |
| QSFP-100G-, QSFP-40/100- | QSFP28 | 100G or dual-rate 40/100G |
| QDD- | QSFP-DD or QSFP-DD800 family | Read the explicit 400G or 800G-class rate from the rest of the PID |
| FET- | Nexus Fabric Extender (FEX) link | Special-purpose optics for FEX links, not general-purpose access links |
| CVR- | Adapter | A form-factor converter, not an optic |
Older GLC PIDs do not always expose the rate. GLC-SX-MMD is a 1G SFP, but other GLC PIDs include 100M and dual-rate exceptions. SFP-10/25G-LR-S, by contrast, states both rates in one speed field; the slash indicates dual-rate capability, not automatic support for both rates on every host.
The host port is equally important. SFP-1G-SX, SFP-1G-LH, and SFP-1G-T-X provide 1G service in supported 10G-capable or multirate ports, but not in a 1G-only SFP port. For form-factor selection and backward compatibility, see the SFP vs QSFP vs QSFP-DD guide.
Media and Reach Codes: Interpret Them by Speed Family
A reach code has meaning only in context. SR, LR, and DR can map to different fiber types, distances, lane arrangements, FEC requirements, and connectors as the speed family changes.
Legacy 1G GLC Codes
Legacy 1G GLC PIDs often combine reach, fiber type, and monitoring in a single block.
| Complete PID | Literal split | Plain-English result |
|---|---|---|
| GLC-TE ยท Cisco 1G SFP modules | [GLC] [T][E] | 1G copper RJ-45; E identifies the extended-temperature variant here; up to 100 m |
| GLC-SX-MMD | [GLC] [SX] [MM][D] | 850 nm multimode with DOM; 220โ550 m on legacy MMF or up to 1 km on supported laser-optimized 50 ฮผm MMF |
| GLC-LH-SMD | [GLC] [LH] [SM][D] | 1310 nm single-mode with DOM; up to 10 km, or 550 m on MMF with the specified conditioning patch cord |
| GLC-EX-SMD | [GLC] [EX] [SM][D] | 1310 nm extended-reach single-mode with DOM; up to 40 km |
| GLC-ZX-SMD | [GLC] [ZX] [SM][D] | 1550 nm long-reach single-mode with DOM; about 70 km, subject to the link budget |
| GLC-BX-D / GLC-BX-U | [GLC] [BX] [-D/-U] | Bidirectional optics for one strand; order the complementary D/U pair |
The letter D serves two different purposes. In MMD and SMD, it denotes digital optical monitoring (DOM); in GLC-BX-D and GLC-BX-U, -D and -U identify complementary wavelength directions. A BiDi link therefore requires a matched D/U pair, not two identical modules.
10G and 25G Reach Codes
At 10G and 25G, the same reach code can specify different maximum distances because the lane rates differ.
| Representative PID or family-scoped code | Medium | Representative maximum reach |
|---|---|---|
| SFP-10G-T-X | Copper, RJ-45 | 30 m at 10G; up to 100 m at 100M/1G |
| SFP-10G-SR-S ยท Cisco 10G optical modules | Multimode, 850 nm | 300 m on OM3 / 400 m on OM4 |
| SFP-25G-SR-S ยท Cisco 25G optical modules | Multimode, 850 nm | 70 m on OM3 / 100 m on OM4; host RS-FEC required |
| SFP-10G-LRM | Legacy multimode or G.652 single-mode, 1310 nm | 220 m on supported legacy MMF / 300 m on G.652 SMF |
| SFP-10G-LR-S, SFP-10/25G-LR-S | Single-mode, 1310 nm | 10 km; 25G operation on relevant PIDs requires host FEC |
| SFP-10G-ER-S | Single-mode, 1550 nm | 40 km |
| SFP-25G-ER-I | Single-mode, approximately 1310 nm | 40 km; host RS-FEC required |
| SFP-10G-ZR-S | Single-mode, 1550 nm | About 80 km, subject to link budget and attenuation requirements |
| SFP-25G-SL | Multimode, 850 nm | 20 m on OM3 / 30 m on OM4; host RS-FEC required |
| SFP-10/25G-CSR-S | Multimode, 850 nm | Up to 300 m on OM3 / 400 m on OM4; full 25G reach requires RS-FEC |
Compare the SR rows: SFP-10G-SR-S reaches 400 m on OM4, while SFP-25G-SR-S is specified for 100 m. That difference is why โSR = 400 mโ is not a safe design rule. For fiber-plant and cost selection rather than PID syntax, see the SFP-10G-LR vs SFP-10G-SR guide.
40G to 400G Codes and Lane Digits
A digit in a 40Gโ400G optical code often describes the number of lanes or wavelengths. It does not, by itself, identify the connector.
| Representative PID or family-scoped code | What the complete code describes | Representative maximum reach |
|---|---|---|
| QSFP-40G-SR4 ยท Cisco 40G optical modules, QSFP-100G-SR4-S ยท Cisco 100G optical modules | Four-lane parallel multimode, MPO | 40G: 100 m OM3 / 150 m OM4; 100G: 70 m OM3 / 100 m OM4 |
| QSFP-40G-CSR4 | Four-lane parallel multimode, MPO | 300 m OM3 / 400 m OM4 |
| QSFP-40G-SR-BD | Wavelength-multiplexed duplex multimode | 30 m on OM2 / 100 m on OM3 / 150 m on OM4 or OM5 |
| QSFP-100G-PSM4-S | Four-lane parallel single-mode, MPO-12 APC | 500 m |
| QSFP-100G-DR-S | One 100G single-mode optical lane, duplex LC | 500 m |
| QDD-400G-DR4-S ยท Cisco 400G optical modules | Four 100G single-mode optical lanes, MPO-12 APC | 500 m |
| FR / FR4 | Single-mode; one lane or four multiplexed lanes, depending on the complete PID | 2 km |
| LR / LR4 / LR8 | Long-reach single-mode with one, four, or eight lanes/wavelengths | 10 km |
| QSFP-100G-CWDM4-S | Four multiplexed single-mode wavelengths | 2 km |
| QDD-400G-VR4, QDD-400G-SR8-S | Parallel multimode with four or eight lanes | VR4: 30 m OM3 / 50 m OM4 or OM5; SR8: 70 m OM3 / 100 m OM4 |
Three examples show why the full PID matters:
- In legacyย GLC-GE-DR-LX, DR means dual rate (100M/1G); inย QSFP-100G-DR-Sย andย QDD-400G-DR4-S, it marks the 500 m single-mode reach class.ย DRย does not have the same meaning in every family.
- At 40G,ย QSFP-40G-CSR4ย is a parallel-MPO optic, whereasย QSFP-40G-CSR-Sย uses duplex LC and four internal wavelengths.
- WSP-Q40GLR4Lย is a legacy 2 km 40G LR4-Lite PID and does not follow the current QSFP pattern.
If a PID does not fit these patterns, consult the exact product data sheet rather than inferring its meaning from the closest match.
Variant Suffixes: Verify the Family-Specific Meaning
Cisco suffixes do not have a consistent meaning across all optics families. Check the documentation for the speed family and exact PID before inferring features from the suffix.
| Ending | Documented meaning | Do not assume |
|---|---|---|
| -S | S-Class on 10G and selected 40G base/-S pairs, including SFP-10G-SR-S and QSFP-40G-SR4-S | It does not mean single-mode. For 100G and 400G PIDs, check the exact product data sheet. |
| -X | Extended-temperature optical variant in documented 10G families, including SFP-10G-SR-X | Capabilities are version-specific: Version 1 of SFP-10G-SR-X is 10GBASE-SR only. Do not apply this definition to copper PIDs such as SFP-10G-T-X or SFP-1G-T-X. |
| -I | Industrial-temperature variant on selected 10G, 25G, and 100G families | Multirate and radio-fronthaul support vary by PID; an industrial optic does not make the rest of the link outdoor-rated. |
| trailing D without a hyphen | DOM support in GLC-SX-MMD and GLC-LH-SMD | This embedded letter is not the BiDi -D direction suffix. |
| -RGD | Rugged, industrial-temperature variant in examples such as GLC-T-RGD | Verify the environmental rating of the complete link, not just the optic. |
| -D / -U | Downstream/upstream wavelength assignment in selected BX families | Order a matched pair. |
Within the documented 1G and 10G families, Cisco defines commercial (COM) as 0 to 70ยฐC, extended (EXT) as -5 to 85ยฐC, and industrial (IND) as -40 to 85ยฐC.
When a base PID and an -S counterpart both exist, do not treat -S as a simple lower-cost label. QSFP-40G-SR4 supports 4x10G breakout; QSFP-40G-SR4-S does not. Compare the two product rows for temperature range, feature support, and platform/software compatibility before substituting one for the other.
Cable PIDs Use Host, Cable Type, and Length
Direct-attach copper (DAC) and active optical cable (AOC) PIDs follow a different pattern: host-side interface, cable or breakout type, then length.
[SFP-H10GB] - [CU] - [3M]
host side cable length
SFP-H10GB-CU3M is a 3 m passive 10G SFP+ copper cable.
| Segment | Meaning | Examples |
|---|---|---|
| CU + length | Passive copper Twinax | SFP-H10GB-CU3M, QSFP-H40G-CU5M, QDD-400-CU2M |
| ACU or AC + length | Active copper for longer runs | SFP-H10GB-ACU10M, QSFP-4X10G-AC7M |
| AOC + length | Active optical cable | SFP-25G-AOC5M, QSFP-100G-AOC15M |
| 4SFP10G, 4SFP25G | Breakout to four SFP-class interfaces at the far end | QSFP-4SFP10G-CU3M, QSFP-4SFP25G-CU2M |
| 4ZQ100, 2Q200 | 400G breakout to four 100G or two 200G interfaces at the far end | QDD-4ZQ100-CU2M, QDD-2Q200-CU3M |
For a breakout assembly, read QSFP-4SFP25G-CU2M as [QSFP host] [4 ร SFP25G interfaces at the far end] [passive copper] [2 m]. The 4SFP25G field identifies those four far-end interfaces; it does not describe the speed of a single connector.
Cable length can also affect host configuration. Cisco’s SFP-H25G-CU passive DAC table specifies no FEC for 1, 1.5, and 2 m cables; BASE-R FEC for 2.5 and 3 m; and RS-FEC for 4 and 5 m. Treat cable length as a host configuration parameter, not just a cable-management detail.
What the PID Cannot Tell You
A PID identifies the module or cable. It cannot confirm platform support, lifecycle status, or suitability for a particular port.
| Question | Encoded in the PID? | Where to verify |
|---|---|---|
| Does the target switch or line card support it? | No | Optics compatibility matrix and the minimum software release |
| Does a base/-S pair support the same features? | No | Exact family data sheet and the two individual product rows |
| Is the module current, end-of-sale, or officially replaced? | No | Current EOL/EOS notice and replacement table |
| Which connector and fiber assembly does the link require? | Not reliably determined from a partial code | Exact product row, followed by the cabling specification |
| Will a third-party-coded optic be accepted and supported? | No | Platform software policy and vendor support terms |
If a port has already rejected or err-disabled a non-Cisco module, use the unsupported transceiver error guide for platform-specific checks and recovery steps.
Verify the Complete BOM Line in the Compatibility Matrix
Use theย Cisco Optics-to-Device Compatibility Matrixย after decoding each PID:
- Search by the switch or line-card PID to list supported transceivers, or by the optic PID to list supported devices.
- Confirm the exact device and optic combination, not only the product families.
- Check the minimum software release against the installed release.
- If the two ends use different module families or generations, check the Cisco Optics-to-Optics Interoperability Matrix.
If the exact combination is absent, treat support as unconfirmed. Mechanical fit does not establish platform or software compatibility.
FAQ
Can every Cisco optics PID be split at each hyphen?ย
No. Hyphens are useful visual separators, but some fields contain additional structure.ย 10/25Gย is one dual-rate speed field,ย SR4ย combines a reach class and lane count, and theย MMDย ending inย GLC-SX-MMDย combines fiber type and DOM. Cable PIDs use a separate host/type/length pattern.
Does the -S in a Cisco optics PID mean single-mode?ย
No. In the 10G family,ย -Sย identifies an S-Class variant. Fiber type comes from the media/reach code:ย SFP-10G-SR-Sย is multimode, whileย SFP-10G-LR-Sย is single-mode. For other speed families, check the exact PID rather than assumingย -Sย has the same meaning everywhere.
Can SFP-10G-SR and SFP-10G-SR-S operate on opposite ends of the same link?ย
The optical interfaces are compatible: both use the same 10GBASE-SR specification. Each host must still support the exact PID installed at its end.
Do Cisco optics part numbers encode the connector type?ย
Not as an independent, universal field. The complete optical code often points to the connector, but a partial code can mislead.ย QSFP-100G-DR-Sย uses duplex LC;ย QDD-400G-DR4-Sย uses MPO-12 APC. Confirm the connector in the exact data-sheet row before ordering patch cables or trunks.
What does GLC stand for?ย
The 1G data sheet describes these products as SFP Gigabit Interface Converters but does not provide an official letter-by-letter expansion ofย GLC. Most GLC PIDs covered here are 1G, but Cisco also has 100M and dual-rate GLC exceptions. Do not infer a meaning for each letter.
What does the = sign after a part number mean?ย
The equals sign identifies the orderable spare PID.ย GLC-TE=ย is the standalone spare form ofย GLC-TE; it does not indicate a different optical or electrical specification.
PID decoding narrows the options; it does not confirm support. If a BOM contains ambiguous optics PIDs, review the Cisco optics range or send us the PID list. Include the target platform and installed software release so we can verify the exact variant, platform compatibility, and availability before you order.
