The work that VITA member company technologists are putting into new standards development projects is immeasurable. It takes special attention to detail and knowledge of the technology and industry to develop the level of standards necessary for this industry. This article is going to dive into behind-the-scenes details on three key projects, highlighting just how difficult it is to develop these standards.
Going into the November VITA Standards Organization (VSO) meeting, more than 30 active study and working groups were busy defining new standards or making significant revisions to existing VITA standards. While this is a slightly higher number of active groups than normal, it is certainly not out of the typical workload. What is significant, however, is that several working groups are involved in high-profile projects that have the potential to make a major impact on the critical and intelligent embedded computing industry in the coming years. High-profile projects are much more challenging to shepherd through the standards development process required by VITA. Considering that most, if not all, of the contributors do this work in their spare time, it is amazing that the projects move to completion as fast as they do.
The current list of active projects includes efforts focused on refining and defining standards for the following:
- Improved definition of operating environments and reliability requirements for critical embedded computing systems.
- New connector standards for:
1. Power-supply connections
2. Optical connectors
3. Higher performance and density connectors for existing standards
- Signal integrity.
- Space applications.
The status for these projects is included in the “VITA standards activity updates” column on page 6.
Three of the active projects are much larger than the rest. Two are next-generation efforts from existing standards. VITA 90 (VNX+) leverages VITA 74 (VNX) to develop a higher-performance version of VNX. VPX Expanded is a study group that is determining what the next generation of the popular VPX standard should look like. The third is an entirely new standard family for a rugged small mezzanine card. Each requires a considerable amount of time and effort to be developed and finalized as an approved VITA standard.
VITA 90 (VNX+)
VITA 74 VNX has been around since 2010 when it was first proposed by Themis Computers (now part of Mercury Systems) as an enhanced small-form-factor system to meet the growing needs of improving size, weight, and power (SWaP) in a rugged, low-cost, fast serial fabric interconnect-based plug-in module. It has gained limited traction in rugged computing applications, providing an attractive solution for platforms needing smaller than 3U solutions. It was limited in performance headroom and other key areas, so the VNX community opened up the standard to take it to the next level. Thus was born VNX+.
While VITA 90 VNX+ is a small form factor, it is extremely complex with a wide range of capabilities unique to this form factor. The goal of the VITA 90 VNX+ family of standards is to build on the foundation established by VITA 74 VNX. The working group has been improving performance capability while at the same time filling in gaps in the family of standards that were not addressed or completed in the original VNX release. VNX+ significantly increases performance and system versatility beyond VITA 74, while following its smaller mechanical framework.
In the early days of the original VNX working group, the participation consisted of a small number of small companies that could move fairly quickly in making decisions pertaining to the standard. Under the new VNX+, the interest level has dramatically increased, along with the drama of completing the standards. The working group has benefited from the increased pool of subject-matter experts participating in the development efforts; at the same time, the discussions are more complex and it is much more difficult to reach consensus! To add to the challenge, companies developing products around the future VNX+ standard are anxious to see a completed set of documents stamped with the VITA approval.
Multiple working groups have been established to develop standards for the various aspects of VNX+. Originally one editor was assigned to the entire suite of dot-standards. Recently the decision was made to assign more editors and giving each of them specific dot-standards to draft. The work as an editor for projects of this size is extremely challenging, requiring a large amount of time to gather inputs, resolve issues, and document the results. These recent changes should enable the working groups to keep moving quickly towards their desired time goals.
The small form factor and system-level focus of VNX+ makes it a very appealing solution for a broad range of industries dependent on critical embedded computing. Companies supporting transportation, defense, and space applications are contributing to the development of these standards.
Mezzanine standards have been around for decades, designed to augment board products that need the ability to add or exchange features. VITA has several mezzanine standards in its repertoire: IP Modules, M-Modules, PMC, XMC, and FMC. VITA 93 is extending to an even smaller size by taking advantage of today’s smaller electronics and is developing a mezzanine form factor that has only recently been possible for the critical embedded computing industry.
VITA 93 defines a small-form-factor mezzanine that is significantly smaller than XMC, with both host and I/O interface connectors. The host interface supports modern high-speed serial fabrics for connectivity. Multiple modules can be installed on various carrier card form factors, including 3U/6U Eurocards (VPX, CompactPCI, VME), VNX+, PCIe expansion cards, and many others. It is suitable for deployment in commercial, industrial, space, or military-grade rugged environments with air-cooled or conduction-cooled formats.
This working group originally started out in 2022 as the VITA 85.109 study group formed to gather requirements from invested participants in the mezzanine supply chain. The study group was chartered to study and document the concept of a new Small Form Factor Mezzanine (SFFm) with certain characteristics not currently addressed by existing mezzanine standards. This was driven by a market need for a mezzanine with the following basic characteristics:
- Significantly smaller than XMC (specifically to be accommodated on the VITA 90 VNX+ form factor which was too small to accommodate any of modern VITA mezzanines).
- Providing two interfaces:
1. A host/primary interface, supporting PCIe speeds beyond Gen2.
2. An I/O/secondary interface, to support either front-panel or backplane I/O.
- Able to be hosted on a range of carrier cards.
- Able to be deployed in either commercial, industrial, or military-grade rugged environments.
It was also desirable to make this new standard as broadly appealing as possible to multiple markets in order to drive up adoption, thus driving down costs and ultimately end-user prices.
The study group met frequently to gather data and discuss options before finally releasing a 56-page report to the VSO that documented the requirements that the new standard must meet, trade study details, and their recommendations for the new standard.
Early in 2023, the study group moved to working group status to begin putting pen to paper to create a draft standard. The working group has since been moving quickly to create a draft document as they sort through the many views on how to solve the challenges needed to be overcome to meet the agreed set of requirements put together by the study group. The level of collaboration in the working group has really had a positive impact on progress.
The resulting standard is bound to open new opportunities for mezzanines to improve the capabilities of board-level products in the coming years.
Following up on defining what is next for VPX is perhaps the biggest challenge for VITA members participating in the VPX ecosystem. VPX has now been around since 2004 and is widely used in the defense industry. It is a complex and expensive technology, but has capabilities found nowhere else in the critical embedded computing industry. VPX in its current form is bound to be with us for decades, but even so a roadmap for performance and capability improvements is necessary.
A study group was formed in 2022 to begin defining the steps and requirements for VPX Expanded. Besides incorporating new technologies, the study group is taking lessons learned from VPX and mapping those against future requirements to determine the best course of action.
The goals set by this study group are to define a solution to expand VPX:
- Double the pin density over the current VPX connectors while keeping the connector length the same.
- Support 100G x 4 at 400 G-baud for the switched serial fabric protocols utilized.
- Improve the P0 connector power capacity to 500 watts and more.
The group desires to leverage existing designs as much as possible. VMEbus was able to maintain a high degree of backwards compatibility over the evolution of the standard. VPX is not going to have that luxury and will require more significant upgrades. There will likely be certain design aspects that can be rolled over to the next generation of products, but new board layouts and backplanes are certainly going to be needed.
The popularity of VPX has attracted many more players to the ecosystem, thus making the next generation even harder to define quickly. Other consortia and standards bodies using VPX are closely monitoring the group’s progress, providing early feedback that should help guide many of the most challenging decisions, especially those related to performance and I/O capability.
As is typical for efforts of this type, most of the discussion at this stage is focused on connector options. The right connector for the backplane interface is critical to meeting all the essential requirements defined by the study group. It is anticipated that this study group will be moving to working groups status in the very near future.
The working group is about to lock down the documented requirements so it can complete a study report. The next step will be to form a working group to begin a draft document.
These projects require a lot of time from the working group participants. Constructive collaboration is a common element of each working group: Each working group chairperson is challenged with keeping all contributors in unison. Hearing out all inputs, discussion, and comments, and then making a decision takes a lot of diplomacy and patience. All of them are under a lot of pressure to produce a document that can be used to start making prototypes critical to proving out the draft standards, making the job even more difficult. They should all be commended for their dedication to the standards working group efforts.