The Common Electrical I/O (CEI) refers to a series of influential Interoperability Agreements (IAs) that have been published by the

Optical Internetworking Forum The Optical Internetworking Forum (OIF) is a prominent non-profit consortium that was founded in 1998. It promotes the development and deployment of interoperable computer networking products and services through implementation agreements (IAs) fo ...

(OIF). CEI defines the electrical and jitter requirements for 3.125, 6, 11, 25-28, and 56

Gbit/s In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multi ...

electrical interfaces.

CEI, the Common Electrical I/O

The Common Electrical I/O (CEI) Interoperability Agreement published by the OIF defines the electrical and jitter requirements for 3.125, 6, 11, 25-28, and 56 Gbit/s SerDes interfaces. This CEI specification has defined

SerDes {{Use American English, date = March 2019 A Serializer/Deserializer (SerDes) is a pair of functional blocks commonly used in high speed communications to compensate for limited input/output. These blocks convert data between serial data and paral ...

interfaces for the industry since 2004, and it has been highly influential. The development of electrical interfaces at the OIF began with SPI-3 in 2000, and the first differential interface was published in 2003. The seventh generation electrical interface, CEI-56G, defines five reaches of 56 Gbit/s interfaces. The OIF began work on its eighth generation with its CEI-112G project. CEI has influenced or has been adopted or adapted in many other serial interface standards by many different standards organizations over its long lifetime. SerDes interfaces have been developed based on CEI for most

ASIC An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficien ...

and

FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware de ...

products.

CEI direct predecessors

Throughout the 2000s, the OIF produced an important series of interfaces that influenced the development of multiple generations of devices. Beginning with the donation of the

PL-3 PL-3 or POS-PHY Level 3 is a network protocol. It is the name of the interface that the Optical Internetworking Forum's SPI-3 Interoperability Agreement is based on. It was proposed by PMC-Sierra to the Optical Internetworking Forum and adopted in ...

interface by

PMC-Sierra PMC-Sierra was a global fabless semiconductor company with offices worldwide that developed and sold semiconductor devices into the storage, communications, optical networking, printing, and embedded computing marketplaces. On January 15, 2016, ...

in 2000, the OIF produced the

System Packet Interface The System Packet Interface (SPI) family of Interoperability Agreements from the Optical Internetworking Forum specify chip-to-chip, channelized, packet interfaces commonly used in synchronous optical networking and Ethernet applications. A typic ...

(SPI) family of packet interfaces.

SPI-3 SPI-3 or System Packet Interface Level 3 is the name of a chip-to-chip, channelized, packet interface widely used in high-speed communications devices. It was proposed by PMC-Sierra based on their PL-3 interface to the Optical Internetworking Foru ...

and

SPI-4.2 SPI-4.2 is a version of the System Packet Interface published by the Optical Internetworking Forum. It was designed to be used in systems that support OC-192 SONET interfaces and is sometimes used in 10 Gigabit Ethernet based systems. SPI-4 is an i ...

defined two generations of devices before they were supplanted by the closely related

Interlaken , neighboring_municipalities= Bönigen, Därligen, Matten bei Interlaken, Ringgenberg, Unterseen , twintowns = Scottsdale (USA), Ōtsu (Japan), Třeboň (Czech Republic) Interlaken (; lit.: ''between lakes'') is a Swiss town and mun ...

standard in the SPI-5 generation in 2006. The OIF also defined the SerDes Framer Interface (SFI) family of specifications in parallel with SPI. As a part of the SPI-5 and SFI-5 development, a common electrical interface was developed termed SxI-5. SxI-5 abstracted the electrical I/O interface away from the individual SPI and SFI documents. This abstraction laid the groundwork for the highly successful CEI family of Interoperability Agreements and was incorporated in the original release of CEI 1.0 a generation later.

Generations of OIF Electrical Interfaces

Two earlier generations in this development path were defined by some of the same individuals at the

ATM Forum The ATM Forum was founded in 1991 to be the industry consortium to promote Asynchronous Transfer Mode technology used in telecommunication networks; the founding president and chairman was Fred Sammartino of Sun Microsystems. It was a non-profit in ...

in 1994 and 1995. These specifications were called UTOPIA Level 1 and 2. These operated at 25

Mbit/s In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multi ...

(0.025 Gbit/s) and 50 Mbit/s per wire single ended and were used in OC-3 (155 Mbit/s) applications. PL-3 was a packet extension of the

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

carried by those earlier interfaces.

Public demonstrations

Compliant implementations to the draft CEI-56G IAs were demonstrated in the OIF booth at the

Optical Fiber Conference Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...

in 2015, 2016 and 2017.

References

{{Reflist Digital electronics Ethernet Synchronous optical networking Fiber-optic communications