Transceiver Module Brand Compatibility Issues

Many large switch brand manufacturers may sell switches at low prices, but when you buy transceiver modules, you will be surprised that the total price of modules is almost equal to or even exceeds the price of switches.

After googling the prices, you will find that there is a wide range of prices in the market. Especially the price of branded transceiver modules is much higher than that of some third-party suppliers. Why is there such a huge price difference?

In addition, when building a network, switches, routers, firewalls and servers of various brands are often used. You are bound to run into some compatibility issues:

• Why does my SFP optical transceiver module work on the Dell switch but not on the Cisco switch?
• How can it happen that a genuine HPE SFP transceiver module works on some HPE switches but not others?
• I have Arista on one side of my network and Brocade on the other, why won’t Arista’s genuine DAC work and neither does Brocade’s genuine DAC?
• Why do SFP modules have so many brand compatibility issues?
• Shouldn’t SFP/QSFP transceiver modules be common to all equipment?

This article is here to tell the story of brand compatibility issues.

Brand Compatibility

There are many compatibility issues in the networking industry. Some are physical layer related and some are protocol layer related. Without these two kinds of compatibility issues, the link shall perform ideally.

However, we know that it is not the case. There is another compatibility issue, brand compatibility, which leads to vendor lock-in. Although the hardware or protocol is compatible, the transceiver module is not working properly. Certain brands of modules must be used to work with switches of the same brand. This means that switch vendors force their customers to use their branded transceiver modules on switches. Vendor lock-in is a matter of greed.

The use of transceiver modules is becoming more and more common. When many information and communication equipment are interconnected at high speed, they will consider optical fiber as a medium to achieve reliable interconnection.

MSA (Multi-Source Agreement)

In order to make transceiver modules available for different industrial applications, it is necessary that a common standard requires standardization to occur naturally. Different industries have different interconnection requirements, which may be differences in data rate, protocol, and signal format. These can be based on IEEE 802.3 Ethernet Standard or FCIA Fiber Channel Standard Specification.

In addition, an MSA (Multi-Source Agreement) is derived from the manufacturer’s agreement to achieve a modular structure, which is applicable to different industries such as Switch, Server, Storage, and Telecommunications.

MSA extends the information and communication industry standard to the module level. In layman’s terms, it covers

Mechanical Interface

• SFP Transceiver Package Dimensions
• Mating of SFP Transceiver PCB to SFP Electrical Connector
• Host Board Layout
• Insertion, Extraction and Retention Forces for SFP Transceivers
• Labeling of SFP Transceivers
• Bezel Design for Systems Using SFP Transceivers
• SFP Electrical Connector Mechanical Specifications
• SFP Cage Assembly Dimensions

Electrical Interface

• Pin Definitions
• Timing Requirements of Control and Status I/O
• Module Definition Interface and Data Field Description

MSAs are especially important in the connector/cabling industry, as their density, line speed, power consumption, and typical costs of an MSA can greatly affect their success in the market. In turn, this can drive connector and media type selection.

Equipment vendors rely on MSA when designing their systems to ensure interoperability and interchangeability between interface modules. Multi-source notation acknowledges the choice end users retain when choosing a module supplier, which helps drive down costs through economies of scale.

Following the MSA, all modules with the same communication specifications can be easily replaced with each other and can be used across brands and between different network equipment. Customers can match transceiver modules and equipment from different manufacturers according to their needs without worrying about compatibility issues.

Now we know, obviously, the story didn’t go that way.

Rebrand and Vendor Lock-in

Transceiver module manufacturers, usually, they are called ODM (Original Design Manufacturers), design and produce transceiver modules. Companies such as II-VI (acquiring Finisar) and Broadcom (acquiring Avago) are well-known ODMs in the transceiver module market. They handle R&D, BOM parts, and factory management operations, but only charge a thin margin based on costs.

Not everyone can buy a mass-produced product all at once, or wait weeks for it to ship. Customers are not buying transceiver modules directly from ODMs. Instead, these modules are bundled with switches, servers, storage, and more. When users or system integrators plan to deploy network infrastructure, they purchase equipment from network equipment manufacturers such as Cisco, HPE, Arista, and others. These large companies do not produce transceiver modules themselves but sell ODM’s products under their own brands. By promoting the transceiver modules with their brand, it drives sales of their own brand portfolio and ensures customer retention. This formed the motivation to bundle their transceiver modules with the equipment. With such a strategy, they may generate more revenue in the transceiver module business.

In order to run this model stably, these network equipment manufacturers will have 2 or more ODMs to provide supply assurance and bargaining power. All ODM information is kept confidential to customers. The entire package displays only its own brand information, including label, box and guide documents. This rebrand marks product listings at 10-100x the ODM selling price. This is why we can see huge price differences for modules of the same specification between branded and compatible ones.

Rebrand cannot prevent customers from using non-branded transceiver modules in their equipment. They do some technology binding to make it happen, which leads to vendor lock-in, in other words, limited brand compatibility.

Taking the SFP transceiver module as an example, there is a small serial EEPROM (Electrically Erasable Programmable Read-Only Memory) or equivalent memory structure inside. Some data is written to it for the host to access. It is standardized by MSA SFF-8472 which defined two-wire interface ID memory map that describes vendor, serial number, part number, manufacturing date, wavelength, fiber type, reach, etc.An enhanced memory map with a digital diagnostic monitoring interface for optical transceivers that allows pseudo real time access to device operating parameters.

Also, some memory is vendor-specific memory, reserved for vendor use. Network equipment manufacturers asked ODM to fill in a so-called security code here, that is, encrypted content. When the SFP module is plugged into the switch, the switch will access the memory through the I2C interface. Check the encrypted content to judge whether it is a self-owned brand transceiver module. If yes, start linking; otherwise, display a warning message about unsupported transceivers or disable the SFP port like Cisco does.

Light Reading has an article Cisco’s Secret Franchise that describes how Cisco benefits from actions that limit brand compatibility, and interested readers can refer to it.

Compatible Transceiver Modules

Life will find its way out.

Third-party transceiver modules are modules manufactured by companies other than branded network equipment suppliers. There is little difference between branded and third-party transceiver modules. Because all transceiver modules are designed and manufactured according to the MSA multi-source agreement, the vendor-specific memory of the third-party module in EEPROM can be set to vendor compatible according to each order. They can be used with equipment from different vendors and can often be used as a replacement for branded equipment.

Sometimes these modules are called compatible modules because they are compatible with branded equipment. Compatible modules typically offer similar performance and functionality to branded ones, but at a lower cost. Many companies want to buy compatible transceiver modules instead of the origin (Cisco, HP, Arista, etc.) for cost-saving reasons. After all, it can save you 80% or more.

There are many third-party suppliers and the product quality is uneven. How to choose a reliable and high-quality third-party supplier has become a key consideration in purchasing. Dawnray Tech’s team has many years of experience and is familiar with industry specifications, module performance and compatibility issues. If you have related product requirements, identification of brand compatibility, or quotation requirements, please contact us.