The XENPAK Optical Transceiver Form-Factor

XENPAK is a fiber optic transceiver form-factor that was developed in the early 2000's. It gets its name from the XENPAK Multisource Agreement (MSA) introduced in 2001.

In the early 2000's a standard for 10 Gigabit transceivers was vital to the spread and adoption of 10 Gigabit Ethernet technology – enter the XENPAK MSA. The XENPAK MSA was the first MSA to specify the form and function of a 10 Gigabit Ethernet transceiver.

As the first 10G capable form-factor, the XENPAK was once a very popular transceiver. While still in use today, XENPAK transceivers have largely been superseded by smaller and more compact 10 Gigabit from-factors, which were developed in subsequent years, such as the XFP, SFP and SFP+.

XENPAK Primary Features:

  • Four Wide XAUI Interface
  • Compliant with all IEEE 802.3ae mediums:
    • 850nm Serial
    • 1310nm WWDM
    • 1310nm Serial
    • 1550nm Serial
  • Hot Pluggable
  • SC Duplex Fiber Optic Connector
  • Industry Standard 70 Pin Connector

Initial Benefits Offered by XENPAK Transceivers:

  • Simplified the management of architecture shifts and integration
  • Minimized downtime required for system upgrades or reconfigurations
  • Reduced system operation costs
  • Multiple vendors assured adequate supply to meet market demands
  • Improved thermal performance for high port density applications
  • Interchangeable via front panel pluggability
  • Supported a "Pay-as-You-Populate" cost structure

The XENPAK MSA has undergone three major revisions since its initial introduction, each one further refining the form-factor.

Revision 2.0, released on September 26th of 2001, finalized the mechanical dimensions, key functionalities, electoral pin-outs and optical interfaces.

Revision 2.1, released on February 15th of 2002, introduced a legal section split; made dimensional changes to the bezel; reduced the PCB thickness range; improved the adaptable power supply; reserved areas in the NVR for intelligent power up and diagnostic functions; and made updates to XENPAK OUI, LASI, and NVR control registers.

Revision 3.0, released on September 18th of 2002, added specifications for XENPAK Digital Optical Monitoring (DOM) functions and added optional low power startup functionality.

A PDF of MSA for Revision 3.0 is available on our website at: XENPAK Multisource Agreement

XENPAK garnered quick support from the industry with a number of companies beginning to ship products that conformed to the MSA in as early as 2001. However, even with the early support, XENPAK transceiver modules were considered too large for high-density applications.

Soon after the introduction of the XENPAK standard, two derivative form-factors emerged: XPAK and X2. The new standards made use of the same XAUI electrical interface as XENPAK but featured differing mechanical properties. The XPAK never gained in commercial popularity.

Beginning in 2010, most vendors began to use& XFP modules for long distance applications, and the new SFP+ module for high-density applications. In addition to being smaller, these form-factors employed a purely serial interface, as opposed to the four lane XAUI interface used in XENPAK transceivers.

For those who prefer to utilize the original 10 Gigabit transceiver, FluxLight offers a large selection of XENPAK transceivers compatible with name brands. A full list of available XENPAK transceivers and prices can be found here.