Catena – Getting back in Control
Stan Moote, CTO, IABM
How do you build a multi-vendor facility and implement a seamless control system? One capable of spanning local hardware, on-prem, off-prem and multi-cloud systems? This article looks at how IABM’s Control Plane working group has been assisting with the Rapid Industry Solutions (RIS) effort within SMPTE called Catena. The working group’s emphasis has had a clear focus to avoid the pitfalls that have aborted several control system standardization efforts over the last couple of decades.
What are those pitfalls?
Standardizing a control system that was specifically designed for an existing product family in the hope that others will “jump on board”
I have seen this approach a few times. Whilst it could work, the proponent is often reluctant or unwilling to modify it to encompass functionality that is identified by the group during standardization. Considerable effort is expended, but the project withers on the vine and the proponent finds something better to do.
Creating a control system standard in a Standards Committee
This approach gets input from a number of stakeholders, however, is incredibly slow! Some of the prime movers will leave over time. New people will join part-way through and argue that the work done should be turned around. Being new work, not field-tested, it may not gain traction with vendors who have their own systems.
Publishing a Control System Standard with no exposure to potential implementers
With something as complicated as a control system, it is important to encourage independent implementations before the documents are finally published. This allows modifications to be made and interoperability testing.
Extending a vendor’s control system in a Standards Committee
The original vendor is often reluctant to expend energy on features that are needed to make the system generic if the vendor does not have need for those features within its product range.
Translators
This approach recognizes that there are many proprietary systems and writes custom protocol translators/convertors for all the vendor products in the system. This soon gets out of control – pardon the pun. It is a maintenance headache.
I have seen systems with dozens of translators mainly because “best-of-breed” products were wanted, each having a dissimilar control protocol/systems making both control and monitoring a nightmare.
Security and Vulnerability
Nobody ever caught a virus over RS-422 or over SDI (often jokingly, yet seriously referred to as Secure Digital Interface). The point-point nature of these interfaces served as an air-gap for content and control flows. Today these both travel over IP networks, and the bad actors out there have racked up plenty of victims with “network” as the attack vector. Simply adding in “IT-style” security doesn’t work due to the instantaneous nature of control and monitoring within our industry.
How have those pitfalls been avoided in Catena?
Catena has been developed in SMPTE’s Rapid Industry Solutions group “Open Services Alliance” (RIS-OSA). It is based on vendors’ knowledge of control system requirements and popular protocols, so it is not starting from scratch.
At IBC 2024, IABM put together a “Control Plane Working Group” that was supported by multiple vendors. At our first on-line meeting, we decided to build a comparison document to see what overlaps there may be. This was also ideal, because within the RIS-OSA group we didn’t want to “reinvent the wheel”. Hence we took the appropriate bits from several industries that were already in use today. For example, reviewing work from the AES-70 and AMWA NMOS working groups.
“Relationship with IABM was essential in the effort to open the communication to the international Vendor community when it came to the discussion about Catena and Control Protocols in SMPTE RIS OSA. This is an important step to create a high-quality document which feeds into the SMPTE Standards process.”
Thomas Bause Mason, Director of Standards Development, SMPTE.
Ciro Noronha, CTO of Cobalt Digital and president of the RIST Forum (RIST is developed by an activity group within the VSF – Video Services Forum) took on the task to create a comparison document for the IABM Control Plane group.
The Control Plane group was given access to the draft documents from RIS-OSA and comments, such as identify feature requirements, were fed back to RIS-OSA before the documents were sent to the SMPTE Standards Group.
The Catena documents are being submitted to SMPTE’s public Committee Draft process. This involves a period of comment resolution after which the documents are publicly released for a period of review, implementation and GitHub comment feedback. The documents are revised in the light of comments received before proceeding through the SMPTE standards balloting process to publication.
Catena directly addresses the security issue – see later in this article.
What’s the current situation with Catena?
Press release from SMPTE shortly after their Standards meeting round:
An Open-Source, Vendor- and Platform-Agnostic Solution, Catena Delivers Single Secure Protocol for Control of Media Devices and Services
At its quarterly SMPTE® Technology Committee meetings, held June 1-3 in Tokyo at Imagica, SMPTE introduced the initial documents defining the Catena control plane standard. The product of extensive work by SMPTE’s Rapid Industry Solutions Open Services Alliance group (RIS-OSA), the initial Catena documents (known as the ST 2138 suite) were introduced to the SMPTE Standards Community (and its 34CS Technology Committee that focuses on Media Systems Control and Services) to begin the official standardization process.
“Catena represents one of the most ambitious and essential standardization efforts SMPTE has undertaken in recent years,” said Chris Lennon, Director of Standards Strategy for Ross Video and a SMPTE Fellow. “With media workflows now spanning on-prem, cloud, and hybrid environments, the need for a unified, secure, and vendor-agnostic control plane is more urgent than ever. By introducing the initial Catena documents into the SMPTE Standards Community, we’re inviting the broader industry to help shape a solution that works for everyone, regardless of where their services reside or what platform they use.”
Hundreds of proprietary protocols are used today to control media devices, creating a control plane challenge across the media industry. In defining and standardizing Catena, SMPTE aims to provide the first and only standardized open-source solution to this challenge. In providing a vendor- and platform-agnostic solution, Catena offers a single secure protocol that is equally suited to controlling very small devices and microservices as it is to controlling the most complex physical devices and services in use by the media industry.
“One of the fundamental challenges facing our industry is managing devices and services across a fragmented infrastructure, and proprietary control protocols are simply not up to the task,” said Thomas Bause Mason, SMPTE Director of Standards Development. “Catena offers a new model based on open standards, community-driven development, and a pragmatic path to implementation. Designed to address every device, service, and system in any environment, it offers the adaptable, future-proof approach we need.”
The initial suite of Catena documents introduced this week consists of:
- ST 2138-00: Catena Overview
- ST 2138-10: Catena Model
- ST 2138-11: gRPC Connection Type
- ST 2138-12: REST Connection Type
- ST 2138-50: Catena Security
These documents are transitioning into SMPTE’s 34CS TC to begin the official standardization process. SMPTE has also stood up its Catena repository on GitHub, which includes interface files, schema, and other supporting resources. SMPTE’s plan is to advance these initial Catena documents to Public Committee Draft (PCD) status as soon as practical, then pause development to give implementers time to integrate Catena into their products and provide feedback. Following this implementation and review period, the documents will quickly move forward through the final standardization and approval stages.
“The industry has long needed a common control layer that actually reflects how we operate today — across clouds, platforms, and vendors,” said Stan Moote, CTO of IABM. “Catena offers a standards-based path forward that brings the transparency and scalability needed for smart, efficient resource management in distributed environments. It’s encouraging to see this kind of progress being made openly, with broad collaboration through SMPTE and engagement from IABM’s Control Plane Working Group, bringing the supplier community into the process.”
A note about Catena security from John Naylor, Ross Video.
I hope one day to claim: “nobody ever caught a virus over Catena”. Time will tell, but you can help – Catena is an Open Source project which means that it can be inspected by anyone and security holes can be spotted and fixed using the SMPTE GitHub repo.
Focusing on control, in broadcast, when we migrated what had worked over RS-422 to IP we did so with little thought to information security. That was excusable in the 90’s and 00’s. It clearly no longer is which is why Catena includes a robust, standards-based approach to security.
Catena security (ST 2138 part 50) requires:
- Transport Layer Security for data in motion – which guarantees authenticity, integrity, and confidentiality.
- Fine-grained access control using the IEEE’s OAuth2 suite of standards – in practical terms this means that you can let your IT admin upgrade devices, but not adjust creative parameters such as EQ settings etc. And by corollary, your TD can punch the show but not upgrade the switcher. If that’s what you want, of course.
But we don’t lose sight of the user’s mission critical aim which is to get (and keep) their content on-air, which is why some of the Zero Trust principles (such as checking every single request against an authorization server) are relaxed to promote better determinism thereby preserving the operator’s artistic intent.
Once again, I hope one day to claim: “nobody ever caught a virus over Catena”. Time will tell.
