How to Specify a 40G QSFP+ Transceiver for an Enquiry or Purchase Order
Knowing how to specify a 40G QSFP+ transceiver helps buyers avoid incompatible coding, unsuitable optical interfaces and costly commissioning delays. Although two modules may fit the same QSFP+ port, they can use different wavelengths, fibre categories, connectors and transmission methods. Therefore, a complete enquiry must define more than the data rate and module form factor.
In particular, buyers should identify the host equipment, compatible coding, optical interface, fibre category, link distance and connector arrangement. In addition, the enquiry should confirm the operating environment, required quantity, accessories and documentation.
The Yamasaki 40G QSFP+ Transceiver Authority Hub explains the broader product range and its applications. This guide, meanwhile, explains how to turn a technical requirement into a clear request for quotation or purchase order.
Information Required for a 40G QSFP+ Enquiry
A complete enquiry should identify:
- Host-equipment manufacturer and model
- Required compatible coding
- 40G optical interface
- Fibre category
- Complete link distance
- Connector type
- Existing cabling arrangement
- Native 40G or breakout operation
- Operating-temperature requirement
- Quantity and accessories
- Required compliance and testing documentation
Where possible, also provide the chassis, line card, port designation and software version. As a result, the supplier can assess the complete application before recommending a module.
For example, avoid sending an enquiry that states only:
Please quote a 40G QSFP+ transceiver.
Although this request identifies the data rate and form factor, it does not define the optical interface, host coding, fibre category or required reach.
Instead, provide a request such as:
Please quote four 40GBASE-LR4 QSFP+ transceivers coded for the nominated switch platform. The modules will operate over existing OS2 singlemode fibre with duplex LC connectors across a 2.5 km route. Commercial operating temperature is acceptable.
Consequently, the supplier can review compatibility, reach and fibre suitability before preparing the quotation.
1. Identify the Host Equipment
First, state the manufacturer and exact model of the equipment receiving the transceiver.
The host equipment may include a:
- Network switch
- Router
- Server network adaptor
- Storage switch
- Firewall
- Telecommunications chassis
- Industrial Ethernet device
- Compatible line card
However, the manufacturer’s name alone may not provide enough information. Different equipment families can apply different compatibility requirements.
Therefore, provide:
- Host manufacturer
- Equipment model
- Chassis model, where applicable
- Line-card or network-adaptor model
- Port designation
- Software or firmware version
- Existing approved transceiver part number, if available
Together, these details help confirm whether the port supports the proposed module, speed and optical interface.
Check the Installed Port
A chassis may accept several line cards with different capabilities. Similarly, some QSFP+ ports support multiple operating modes, whereas others support only specific configurations.
Consequently, check the installed equipment rather than relying solely on the general chassis specification. In particular, confirm the actual line card, port and software version.
A QSFP-shaped port does not automatically support every 40G QSFP+ module. For example, the host may restrict supported interfaces, third-party coding or breakout operation.
If the project remains at the design stage, clearly state that the host equipment has not yet been selected. The supplier may still help identify a suitable optical interface. However, final compatible coding cannot be confirmed until the equipment platform becomes known.
For further guidance, review the 40G QSFP+ Compatibility Guide.
2. State the Required Compatible Coding
Compatible coding allows the host equipment to recognise and communicate with the transceiver. Therefore, the enquiry should identify the required platform compatibility.
Suitable descriptions include:
- Coded for the nominated equipment model
- Compatible with the existing host platform
- Programmed to match an approved transceiver
- Generic coding for an open platform
- Dual-platform coding, where supported
If an existing module operates successfully, provide its full part number and a clear photograph of its label. Nevertheless, do not rely on latch colour, packaging or a shortened product description.
Specify Both Endpoints
The equipment at each end may come from different manufacturers. In that case, identify each host separately.
For example:
- End A: coded for Platform A
- End B: coded for Platform B
- Optical interface: 40GBASE-LR4 at both ends
Although the compatible coding may differ, the optical interfaces must remain mutually compatible. In other words, coding relates to the host platform, while the optical interface determines how the modules communicate across the fibre.
Compatibility may also depend on the software version, line card, port configuration and third-party transceiver policy. Accordingly, provide complete equipment information before ordering.
3. Select the 40G Optical Interface
QSFP+ describes the physical module form factor. However, it does not define the optical interface.
Common 40G interfaces include:
| Interface | Typical fibre | Connector | General application |
|---|---|---|---|
| 40GBASE-SR4 | OM3 or OM4 multimode | MPO/MTP | Short-reach parallel-optics links |
| 40GBASE-ESR4 | OM3 or OM4 multimode | MPO/MTP | Extended multimode links |
| 40GBASE-LR4 | OS2 singlemode | Duplex LC | Campus and backbone links |
| 40GBASE-ER4 | OS2 singlemode | Duplex LC | Extended-distance singlemode links |
| 40G PSM4 | OS2 singlemode | MPO/MTP | Parallel singlemode links |
| 40G LR4 Lite | OS2 singlemode | Duplex LC | Shorter singlemode applications |
| 40G BiDi | Supported multimode channel | Duplex LC | Reuse of suitable duplex fibre |
| 40G breakout | Depends on selected optics | MPO/MTP or harness | Four separate 10G connections |
For an independent technical overview of 40 Gigabit Ethernet physical-layer specifications, fibre media and supported reaches, refer to the 40 Gigabit Ethernet and 100 Gigabit Ethernet Technology Overview published by the Ethernet Alliance.
Actual reach and host support depend on the selected product. Therefore, confirm the relevant specifications before placing the order.
Do Not Select the Interface by Distance Alone
Several optical interfaces may support the same route length. However, they can require completely different fibre and connector systems.
For instance, a short 40G link might use:
- SR4 over parallel OM4 fibre
- BiDi over suitable duplex multimode fibre
- LR4 Lite over duplex OS2 fibre
- PSM4 over parallel OS2 fibre
Consequently, identify the installed fibre and connector arrangement before selecting the interface. Otherwise, the module may fit the host while remaining incompatible with the passive fibre channel.
Moreover, consider future network requirements. For example, a proposed breakout application may require parallel fibre and suitable lane mapping, while a native duplex link may favour an LC-based interface.
For a broader overview of available interfaces, fibre options and applications, review the Yamasaki 40G QSFP+ Transceiver Authority Hub before finalising the module specification.
4. Confirm the Fibre Category
Next, state the installed or proposed fibre category.
Relevant categories include:
- OM3 multimode fibre
- OM4 multimode fibre
- OS2 singlemode fibre
Avoid stating only “multimode” or “singlemode” when the precise category is known. After all, the fibre category affects the supported reach, interface selection and channel performance.
For an existing installation, check:
- Cable jacket markings
- Patch-lead markings
- Fibre certification reports
- Patch-panel labels
- Installation records
- Previous project documentation
However, colour alone does not conclusively identify the fibre. Replacement leads, mixed components or non-standard colours may create uncertainty. Therefore, use reliable documentation or suitable testing where necessary.
In addition, specify the complete end-to-end path. Patch leads, cassettes, adaptors and permanent cabling must all suit the proposed interface.
For example, a channel that combines different multimode fibre categories may not support the intended reach. Likewise, a connector adaptor cannot make singlemode optics compatible with multimode fibre.
The 40G QSFP+ Distance and Fibre Type Guide provides further guidance on matching the optical interface to the fibre category and required reach.
5. State the Complete Link Distance
Record the full optical route length between the two transceivers.
In particular, include:
- Permanent cabling
- Patch leads
- Equipment-room routing
- Service loops
- Intermediate distribution areas
- Additional cabinet routing
If the exact distance remains unknown, provide the expected route length and a practical design allowance.
For example:
Required reach: approximately 850 metres, including patch leads, cabinet routing and service loops.
Avoid vague descriptions such as “short range” or “long range”. Instead, state the estimated distance in metres or kilometres.
Longer Reach Is Not Always Better
Selecting the longest-reach module does not necessarily create a safer design. In fact, longer-reach optics may:
- Cost more
- Consume more power
- Generate more heat
- Require different optical-power management
- Overload a receiver on a short link
- Need attenuation in some installations
Therefore, select an interface suited to the actual channel rather than choosing the longest available reach.
Moreover, consider optical loss as well as physical distance. Connectors, splices, cassettes, contamination and fibre bends all reduce the available power margin. As a result, a link can remain within the distance limit while exceeding the permitted loss budget.
6. Define the Connector Arrangement
State the connector required at the transceiver interface.
Common arrangements include:
- Duplex LC
- MPO/MTP
- Dedicated breakout assembly
For example, standard LR4 modules generally use duplex LC connectivity, whereas SR4 modules commonly use parallel MPO/MTP connectivity.
Nevertheless, connector type alone does not define the fibre or optical interface. The descriptions “LC fibre” and “MPO fibre” remain incomplete because LC and MPO/MTP identify connector systems rather than fibre categories.
Instead, specify combinations such as:
- Duplex LC over OS2 singlemode fibre
- MPO/MTP over OM4 multimode fibre
- MPO/MTP over parallel OS2 singlemode fibre
Provide Complete MPO/MTP Details
Where MPO/MTP connectivity applies, also confirm:
- Fibre count
- Connector gender
- Alignment-pin arrangement
- Key orientation
- End-to-end polarity
- Active fibre positions
- Trunk or harness arrangement
- Native 40G or breakout operation
Although two connectors may mate physically, the transmit and receive lanes may not align correctly. Therefore, the enquiry must describe the complete parallel-optics architecture.
7. Describe the Existing Fibre Route
If the project uses installed infrastructure, explain how the fibre travels between the two ports.
Useful details include:
- Direct or patch-panel connection
- Number of intermediate connections
- Installed trunk type
- Cassette arrangement
- Splice locations
- Connector types
- Available fibre count
- Existing polarity
- Recent test results
- Measured channel insertion loss
For example:
Switch A connects through an OS2 duplex LC patch lead to an LC patch panel. The permanent OS2 link runs 1.8 km to a second patch panel, followed by another duplex LC patch lead to Switch B.
Alternatively:
The route uses a 12-fibre OM4 MPO/MTP trunk between two cabinets without cassettes. The proposed application is native 40GBASE-SR4.
In both cases, the supplier can assess the transceiver against the complete installed channel. Furthermore, a route description can expose missing adaptors, unsuitable patch leads or incorrect connector assumptions before ordering.
Where possible, attach a simple route diagram and recent test results. Consequently, the supplier can review the physical arrangement and available optical margin together.
8. Identify Any Breakout Requirement
A breakout configuration divides one 40G port into four separate 10G connections. However, the host port, module, cabling and far-end interfaces must all support the arrangement.
State whether the project requires:
- One native 40G link
- Four independent 10G links
- A direct-attach copper breakout cable
- An active optical breakout cable
- A QSFP+ module with a fibre breakout harness
For an optical breakout, also provide:
- Far-end equipment models
- Required SFP+ interfaces
- Fibre category
- Connector arrangement
- Individual lane destinations
- Required reach for each connection
A QSFP+ port does not automatically support 4 × 10G breakout. Therefore, confirm that the host software exposes four logical interfaces and supports the proposed port configuration.
In addition, verify that the far-end SFP+ modules use compatible optical interfaces. Otherwise, the physical components may connect while the individual lanes fail to establish links.
9. Specify the Operating Environment – How to Specify a 40G QSFP+ Transceiver
State the required operating-temperature range.
Common classifications include:
- Commercial temperature
- Extended temperature
- Industrial temperature
However, the exact temperature range varies between products. Accordingly, provide the required minimum and maximum temperatures for applications outside controlled equipment rooms.
In particular, consider:
- Outdoor cabinets
- Industrial plants
- Mining operations
- Transport infrastructure
- Unconditioned enclosures
- High-density equipment
- Restricted airflow
- Seasonal temperature variation
An industrial-temperature module does not replace suitable ventilation or thermal design. Moreover, the host equipment, power supply and passive components must also suit the expected environment.
Even in an air-conditioned room, the temperature near a densely populated switch can exceed the general room temperature. Therefore, assess the conditions at the equipment rather than relying solely on the building thermostat.
10. Confirm Quantity and Accessories
State the number of modules required for each compatible coding.
Remember:
- One point-to-point link normally requires two modules
- Four point-to-point links normally require eight modules
- A breakout may require one QSFP+ and four SFP+ modules
- Critical applications may require additional spares
If the endpoints use different platforms, divide the quantity accordingly.
For example:
- 6 × modules coded for Platform A
- 6 × modules coded for Platform B
- 2 × Platform A-coded spares
- 2 × Platform B-coded spares
In addition, identify any required:
- Fibre patch leads
- MPO/MTP trunks
- Breakout harnesses
- Adaptors
- Optical attenuators
- Cleaning consumables
- Spare modules
Consequently, the supplier can prepare a complete bill of materials instead of supplying transceivers without the components needed for commissioning.
Furthermore, separate each coding and product type on the purchase order. As a result, both parties can verify the required quantities without relying on notes or assumptions.
11. Request the Required Documentation
Specify documentation requirements during the quotation stage.
Possible requirements include:
- Product datasheet
- Declaration of conformity
- RoHS or REACH documentation
- Serial-number schedule
- Individual test reports
- Optical test results
- Coding confirmation
- Batch traceability
- Country-of-origin information
- Warranty statement
- Certificate of conformance
Avoid requesting “all certificates” without defining the actual requirement. Instead, identify the records required by the client, consultant or project quality plan.
Some documents may require additional testing or project identification. Consequently, requesting them after delivery may cause delays or additional costs.
Where a contract nominates a standard, also provide the standard number and required edition. In addition, clarify whether the project needs a supplier declaration, independent test evidence or a formal certificate.
How to Specify a 40G QSFP+ Transceiver – Recommended 40G QSFP+ Enquiry Template
Use the following template when requesting a quotation.
Host Equipment
- End A manufacturer and model:
- End A line card or adaptor:
- End A software version:
- End A required coding:
- End B manufacturer and model:
- End B line card or adaptor:
- End B software version:
- End B required coding:
Optical Requirement
- Required 40G interface:
- Native 40G or breakout:
- Fibre category:
- Complete route distance:
- Connector arrangement:
- Existing cabling description:
- Number of connection points:
- Available fibre count:
- Known insertion loss:
- Operating-temperature range:
Quantity and Documentation
- End A module quantity:
- End B module quantity:
- Spare quantity:
- Patch leads or harnesses:
- Required test reports:
- Required compliance documents:
- Required delivery date:
Where relevant, attach module photographs, route diagrams and fibre test reports. In addition, include the part number of any approved module already operating in the same host equipment.
Common 40G QSFP+ Ordering Mistakes
Understanding how to specify a 40G QSFP+ transceiver also means avoiding common ordering errors.
Ordering by Form Factor Alone
“40G QSFP+” does not identify the optical interface. Therefore, also state the fibre category, connector, reach and compatible coding.
Assuming Physical Fit Confirms Compatibility
A module may fit the port while remaining unsupported by the host. Consequently, check the exact equipment, line card, software and port requirements.
How to Specify a 40G QSFP+ Transceiver and Specifying Only One Endpoint
A link involves two hosts and two transceivers. Accordingly, provide the equipment and coding requirements for both ends.
Matching Connectors but Not Optical Interfaces
Two modules may use duplex LC connectors while operating with incompatible wavelengths or transmission methods. Thus, connector type alone cannot confirm compatibility.
Confusing Multimode and Singlemode Products
SR4 and LR4 both support 40G Ethernet. However, they require different fibre channels. Therefore, a connector adaptor cannot correct incompatible optics or fibre.
Ignoring MPO/MTP Polarity
MPO/MTP connectors can mate while maintaining the wrong lane arrangement. Consequently, verify gender, polarity, key orientation and active fibre positions.
Forgetting Breakout Support
Not every 40G port supports 4 × 10G operation. Therefore, confirm host support before ordering the module, cable or harness.
Ignoring the Optical Power Budget
A longer-reach module may overload a receiver on a short link. Conversely, excessive channel loss may prevent operation over a route within the nominal distance.
The 40G QSFP+ Optical Power Budget and Link-Loss Guide explains how transmitter output, channel loss and receiver limits affect product selection.
Ordering Modules Without Accessories
Correct transceivers cannot complete the link without suitable patch leads or breakout assemblies. Therefore, include the complete connection system in the order.
Requesting Documentation After Delivery
Some test reports and project documents require advance preparation. Accordingly, define every documentation requirement during the quotation stage.
Review the Quotation Before Ordering
Before issuing the purchase order, check that the quotation confirms:
- Module part number
- Optical interface
- Compatible coding
- Quantity for each coding
- Fibre category
- Connector type
- Supported reach
- Temperature classification
- Included accessories
- Required documentation
- Warranty and delivery terms
If the quotation uses an abbreviated description, request clarification. For example, “40G LR module” may not identify the exact interface, connector arrangement or host coding.
Therefore, the final purchase order should contain enough information for both parties to identify the required product. However, where the endpoints require different coding, list them as separate line items.
Verify the Delivered Modules
After delivery, compare the products with the approved purchase order before installation.
In particular, check:
- Product part number
- Compatible coding
- Optical interface
- Connector type
- Wavelength information
- Temperature rating
- Quantity
- Serial numbers
- Packaging condition
- Supplied documentation
If a label or document conflicts with the approved order, quarantine the affected module until the supplier confirms its suitability.
Meanwhile, keep dust plugs fitted until technicians inspect and connect the fibre. However, never assume that a new connector is clean merely because it arrived with a dust cap.
After confirming the products, follow a controlled installation and commissioning process. The 40G QSFP+ Installation and Commissioning Guide explains how to prepare the equipment, inspect the fibre, install the module and validate the completed link.
Frequently Asked Questions – How to Specify a 40G QSFP+ Transceiver
Is “40G QSFP+ transceiver” enough information for an order?
No. It does not define the optical interface, compatible coding, fibre category, connector type, reach or operating environment. Therefore, provide the complete application requirements.
Do both ends require the same compatible coding?
Not always. Different host platforms may require different coding. However, the optical interfaces at both ends must remain mutually compatible.
Do I need two transceivers?
A normal point-to-point link requires one transceiver at each end. However, a breakout arrangement may use one QSFP+ module and four far-end SFP+ modules.
Can I select the longest available reach to be safe?
No. Longer-reach optics may increase cost, power consumption and receiver-overload risk. Therefore, select a module suited to the actual channel.
What if I do not know the required interface?
Provide the host models, fibre category, connector system, route distance and intended application. Anderson Corporation can then assess the available options.
Should I include existing fibre test results?
Yes. Where available, insertion-loss reports help determine whether the installed channel provides sufficient optical margin. In addition, they may identify faults that require correction before commissioning.
When should I request compliance documentation?
Request it during the quotation stage. As a result, the supplier can confirm availability, cost and lead time before you place the order.
Prepare a Complete 40G QSFP+ Order
Knowing how to specify a 40G QSFP+ transceiver requires a complete view of the host equipment, optical interface and passive fibre channel. First, identify both host platforms and their required compatible coding. Next, define the fibre category, route distance and connector arrangement. Then, confirm the operating environment, quantity, accessories and documentation.
As a result, the supplier can assess compatibility before supply and prepare a complete bill of materials. Furthermore, this process reduces unsuitable module selections, missing accessories and commissioning delays.
Finally, compare the quotation with the approved technical requirement before issuing the purchase order. Additionally, for product selection or a formal quotation, review the Yamasaki 40G QSFP+ Transceiver Authority Hub. Alternatively, send Anderson Corporation the completed enquiry template together with the host, fibre, distance and documentation requirements.