XENPAK is a multisource agreement (MSA), instigated by Agilent Technologies and Agere Systems, that defines a fiber-optic or wired transceiver module which conforms to the 10 Gigabit Ethernet (10GbE) standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group.
[1] Although the XENPAK agreement received early support, its modules were thought to be overly large for high-density applications.
Newer XENPAKs using the 10GBase-LX4 standard operated using multiple wavelengths on legacy multi-mode fibers at distances of up to 300 metres (980 ft), eliminating the need to reinstall cable in a building when upgrading certain 1 Gbit/s circuits to 10 Gbit/s.
The XENPAK form factor was initially supported by numerous network equipment manufacturers and module makers.
[6] Issue 3.0 of the XENPAK MSA was transferred to the Small Form Factor committee as document INF-8474 on September 18, 2002.