Common Electrical I/O

Last updated

The Common Electrical I/O (CEI) refers to a series of influential Interoperability Agreements (IAs) that have been published by the Optical Internetworking Forum (OIF). CEI defines the electrical and jitter requirements for 3.125, 6, 11, 25-28, and 56 Gbit/s electrical interfaces.

Contents

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 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 completed work on its eighth generation through its CEI-112G project. [1] The OIF has launched its ninth generation with its CEI-224G project. [2] 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 and FPGA 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 interface by PMC-Sierra in 2000, the OIF produced the System Packet Interface (SPI) family of packet interfaces. SPI-3 and SPI-4.2 defined two generations of devices before they were supplanted by the closely related Interlaken 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

Gen.IA
Title		Pub.
as		Clause
#'s		Max
per pair		Mult.
of bit
rate
per wire		Typical
appli
-cation		Year
pub.		Adopted,
adapted or
influenced		Num.
ranges		Modu-
lations
9CEI-224G232 Gbit/s1160x1600GE thru 200GEIEEE 802.3djPAM-4
8CEI-112GCEI 5.0 [3] 23-4, 26-7116 Gbit/s580x800GE thru 100GE2022IEEE 802.3ck, Infiniband NDR, 128G Fibre Channel and others4PAM-4 and CNRZ-5
7CEI-56GCEI 4.0 [4] [5] 16-2256 Gbit/s290x 400GE thru 50GE2017IEEE 802.3bs and 802.3cd, Infiniband HDR, 64G Fibre Channel 5NRZ, PAM-4 and ENRZ
6.5CEI-28G (added 25G LR)CEI 3.1 [6] 1128 Gbit/s (25 for LR)140x100GE thru 25GE2011 InfiniBand EDR, 32G Fibre Channel, SATA 3.2, IEEE 802.3 100GBASE-KR4, 100GBASE-CR4 and CAUI4, SAS-4, Interlaken 1.94NRZ
6CEI-28GCEI 3.0, [7] 10, 12-1428 Gbit/s140x100GE thru 25GE2008 InfiniBand EDR, 32GFC, SATA 3.2, IEEE 802.3 CAUI4, SAS-4, Interlaken 1.94NRZ
5CEI-11GCEI 2.08-911 Gbit/s55xOC-768, 100GE, 40GE2008InfiniBand QDR, 10GBASE-KR, 10GFC, 16GFC, SAS-3, RapidIO v3, Interlaken3NRZ
4CEI-6GCEI 1.06-76 Gbit/s30x OC-768 (~40 Gbit/s)20044GFC, 8GFC, InfiniBand DDR, SATA 3.0, SAS-2, RapidIO v2, HyperTransport 3.1, Interlaken2NRZ
3SxI-5SxI-5 [8] and CEI 1.04-53.125 Gbit/s16x OC-192, 10GE 2002, 2004 Interlaken, SPI-5, SFI-5, FC 2G, InfiniBand SDR, XAUI, 10GBASE-KX4, 10GBASE-CX4, SATA 2.0, SAS-1, RapidIO v11NRZ
2 SPI-4.2 SPI-4, 4.2 [9] 0.8 Gbit/s4xOC-48 (2.488 Gbit/s)2001-2HyperTransport 1.031NRZ
1 SPI-3 SPI-30.1 Gbit/s (single ended)1 (ref) OC-12 (0.622 Gbit/s)2000(From PMC-Sierra's PL-3)1NRZ

Two earlier generations in this development path were defined by some of the same individuals at the ATM Forum in 1994 and 1995. These specifications were called UTOPIA Level 1 and 2. These operated at 25 Mbit/s (0.025 Gbit/s) and 50 Mbit/s per wire single ended and were used in OC-3 (155 Mbit/s) applications. [10] PL-3 was a packet extension of the cells 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 in 2015, 2016 and 2017. [11]

Related Research Articles

<span class="mw-page-title-main">USB</span> Standard for computer data connections

Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.

<span class="mw-page-title-main">Serial digital interface</span> Family of digital video interfaces

Serial digital interface (SDI) is a family of digital video interfaces first standardized by SMPTE in 1989. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video. A related standard, known as high-definition serial digital interface (HD-SDI), is standardized in SMPTE 292M; this provides a nominal data rate of 1.485 Gbit/s.

<span class="mw-page-title-main">Small Form-factor Pluggable</span> Modular communications interface

Small Form-factor Pluggable (SFP) is a compact, hot-pluggable network interface module format used for both telecommunication and data communications applications. An SFP interface on networking hardware is a modular slot for a media-specific transceiver, such as for a fiber-optic cable or a copper cable. The advantage of using SFPs compared to fixed interfaces is that individual ports can be equipped with different types of transceivers as required, with the majority including optical line terminals, network cards, switches and routers.

<span class="mw-page-title-main">RapidIO</span> High-speed interconnect technology

The RapidIO architecture is a high-performance packet-switched electrical connection technology. It supports messaging, read/write and cache coherency semantics. Based on industry-standard electrical specifications such as those for Ethernet, RapidIO can be used as a chip-to-chip, board-to-board, and chassis-to-chassis interconnect.

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) for optical networking products and component technologies including SerDes devices.

<span class="mw-page-title-main">Current-mode logic</span> Differential digital logic family

Current mode logic (CML), or source-coupled logic (SCL), is a digital design style used both for logic gates and for board-level digital signaling of digital data.

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 typical application of such a packet level interface is between a framer or a MAC and a network processor. Another application of this interface might be between a packet processor ASIC and a traffic manager device.

Optical Carrier transmission rates are a standardized set of specifications of transmission bandwidth for digital signals that can be carried on Synchronous Optical Networking (SONET) fiber optic networks. Transmission rates are defined by rate of the bitstream of the digital signal and are designated by hyphenation of the acronym OC and an integer value of the multiple of the basic unit of rate, e.g., OC-48. The base unit is 51.84 Mbit/s. Thus, the speed of optical-carrier-classified lines labeled as OC-n is n × 51.84 Mbit/s.

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 parallel interfaces in each direction. The term "SerDes" generically refers to interfaces used in various technologies and applications. The primary use of a SerDes is to provide data transmission over a single line or a differential pair in order to minimize the number of I/O pins and interconnects.

<span class="mw-page-title-main">Ethernet physical layer</span> Electrical or optical properties between network devices

The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed of the physical connection between a device and the network or between network devices. It is complemented by the MAC layer and the logical link layer. An implementation of a specific physical layer is commonly referred to as PHY.

Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network technologies between a telecommunications company and a customer's premises. From the customer's point of view, it is their first mile, although from the access network's point of view it is known as the last mile.

40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet (100GbE) are groups of computer networking technologies for transmitting Ethernet frames at rates of 40 and 100 gigabits per second (Gbit/s), respectively. These technologies offer significantly higher speeds than 10 Gigabit Ethernet. The technology was first defined by the IEEE 802.3ba-2010 standard and later by the 802.3bg-2011, 802.3bj-2014, 802.3bm-2015, and 802.3cd-2018 standards. The first succeeding Terabit Ethernet specifications were approved in 2017.

A multi-gigabit transceiver (MGT) is a SerDes capable of operating at serial bit rates above 1 Gigabit/second. MGTs are used increasingly for data communications because they can run over longer distances, use fewer wires, and thus have lower costs than parallel interfaces with equivalent data throughput.

SerDes Framer Interface is a standard for telecommunications abbreviated as SFI. Variants include:

<span class="mw-page-title-main">UniPro</span> High-speed interface technology

UniPro is a high-speed interface technology for interconnecting integrated circuits in mobile and mobile-influenced electronics. The various versions of the UniPro protocol are created within the MIPI Alliance, an organization that defines specifications targeting mobile and mobile-influenced applications.

The C form-factor pluggable is a multi-source agreement to produce a common form-factor for the transmission of high-speed digital signals. The c stands for the Latin letter C used to express the number 100 (centum), since the standard was primarily developed for 100 Gigabit Ethernet systems.

Terabit Ethernet (TbE) is Ethernet with speeds above 100 Gigabit Ethernet. The 400 Gigabit Ethernet and 200 Gigabit Ethernet standard developed by the IEEE P802.3bs Task Force using broadly similar technology to 100 Gigabit Ethernet was approved on December 6, 2017. On February 16, 2024 the 800 Gigabit Ethernet standard developed by the IEEE P802.3df Task Force was approved.

25 Gigabit Ethernet and 50 Gigabit Ethernet are standards for Ethernet connectivity in a datacenter environment, developed by IEEE 802.3 task forces 802.3by and 802.3cd and are available from multiple vendors.

FlexE, short for Flexible Ethernet, is a communications protocol published by the Optical Internetworking Forum (OIF).

An optical module is a typically hot-pluggable optical transceiver used in high-bandwidth data communications applications. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside world through a fiber optic cable. The form factor and electrical interface are often specified by an interested group using a multi-source agreement (MSA). Optical modules can either plug into a front panel socket or an on-board socket. Sometimes the optical module is replaced by an electrical interface module that implements either an active or passive electrical connection to the outside world. A large industry supports the manufacturing and use of optical modules.

References

  1. ↑ "OIF Launches CEI-112G Project for 100G Serial Electrical Links" (Press release). Businesswire, 30 Aug 2016. 30 August 2016.
  2. ↑ "OIF to Update Industry on Next-Generation Electrical and Optical Interface Projects, including 224 Gbps & Co-Packaging, at DesignCon 2023". OIF, 11 Jan 2023.
  3. ↑ "Common Electrical I/O (CEI) - Electrical and Jitter Interoperability agreements for 6G+ bps, 11G+ bps, 25G+, 56G+ and 112G+ bps I/O" (PDF). OIF, May 2022.
  4. ↑ "Common Electrical I/O (CEI) - Electrical and Jitter Interoperability agreements for 6G+ bps, 11G+ bps, 25G+, and 56G+ bps I/O" (PDF). OIF, Dec 2017.
  5. ↑ "OIF CEI Technology For 56 Gbps Available For Wider Industry Adoption". OIF, Jan 2018.
  6. ↑ "Common Electrical I/O (CEI) - Electrical and Jitter Interoperability agreements for 6G+ bps, 11G+ bps and 25G+ bps I/O" (PDF). OIF, 8 Feb 2014.
  7. ↑ "Common Electrical I/O (CEI) - Electrical and Jitter Interoperability agreements for 6G+ bps, 11G+ bps and 25G+ bps I/O" (PDF). OIF, Sept 2011. Archived from the original (PDF) on 2018-01-18. Retrieved 2017-05-08.
  8. ↑ "System Interface Level 5 (SxI-5): Common Electrical Characteristics for 2.488 – 3.125Gbps Parallel Interfaces" (PDF). OIF, Oct 2005. Archived from the original (PDF) on 2018-02-19. Retrieved 2017-05-08.
  9. ↑ "System Packet Interface Level 4 (SPI-4) Phase 2 Revision 1: OC-192 System Interface for Physical and Link Layer Devices" (PDF). OIF, 15 Oct 2003.[ permanent dead link ]
  10. ↑ "OIF shows 56G electrical interfaces & CFP2-ACO". Gazzettabyte, 25 Mar 2015.
  11. ↑ "ATM Physical Layers" (PDF). Washington University in St. Louis (originally published by Ohio State), ~1998.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.