Compact Modular and Carrier Grade: The Match We’ve Been Waiting For

Over the past few years, the platforms used to build optical networking infrastructure have undergone a dramatic change. While traditional platforms were large, multi-slot, closed systems, this new breed of platform – called “compact modular” – is smaller with fewer slots and open software architectures. In addition to providing a more cost-effective platform, compact modular systems simplify and accelerate deployment, help to break vendor lock-in, and facilitate the rapid introduction of new technologies and services.

Compact modular platforms were initially designed for point-to-point data center interconnect (DCI) applications and optimized for the software-centric operational paradigm employed by internet content providers (ICPs). However, after several years of deployments, it has become clear that these platforms can provide benefits across a much wider range of applications, and that the more dynamic software-centric approach that they enable is beneficial to network operators beyond just ICPs. As a result, the last few years have seen a significant increase in the networking capabilities being built into these compact modular systems and a rise in the adoption of these platforms by a much broader set of network operators, including traditional communications service providers (CSPs).

As a matter of fact, Dell’Oro’s Optical Quarterly Summary from March 2021 highlights that compact modular revenue grew sharply in 4Q20 at 52% year over year due to the expanded market beyond ICPs. More specifically, Dell’Oro estimates that compact modular revenue outside of ICPs increased 165% year over year in the quarter and accounted for 46% of total compact modular revenue. A major part of this increase is the result of the rapid adoption of compact modular platforms by CSPs. And this is just the start. Widespread deployment by CSPs will require these compact modular platforms to support a host of “carrier-grade” features that enable them to meet the more stringent reliability and safety requirements typical of CSP deployments.

So, What Is “Carrier Grade”?

By definition, carrier grade refers to a hardware or software system that has extremely high reliability, is engineered to meet or exceed “five nines” or 99.999% availability standards, and provides very fast fault recovery through redundancy.

The latest generation of compact modular platforms, such as Infinera’s GX Series G42, has been designed to deliver carrier-grade features to enable seamless deployment into CSPs’ infrastructure. Some of these carrier-grade features and capabilities are briefly described below:

• Redundant controllers: A controller is the brains of the system, providing a broad range of communication, control, and alarm surveillance capabilities. Carrier-grade compact modular platforms boast two independent and field-replaceable controller units that can quickly take over for each other in the case of failure, greatly increasing the availability and reliability of the system.

Figure 1: Dual controllers on the G42 compact modular platform

• NEBS Level 3 compliance: Network Equipment-Building System (NEBS) is the most common set of safety, spatial, and environmental design guidelines applied to telecommunications equipment in the United States. It governs things like operating temperatures, vibration resistance, airflow patterns, radio frequency emissions, and fire suppression. NEBS Level 3 is a standard requirement for many CSPs to meet their own operational and reliability standards as well as government regulations.

• Multi-chassis control: Typical CSPs’ networks consist of thousands of network elements carrying hundreds of thousands of client services across a large geographical area. Minimizing the total number of independent elements that must be managed is a priority for many network operators. With multi-chassis control, a single network element is capable of managing numerous subtended network elements, turning those numerous elements into a single virtual element and greatly simplifying operations and reducing operational expenses. 

Figure 2: Multi-chassis Control

• Ability to fit into 300-mm or 600-mm ETSI racks: When designing offices to host networking equipment, network operators design their facilities based on certain physical dimensions. While most ICPs have designed facilities to support elements that are 600 mm deep, most CSPs have numerous facilities designed to support only platforms that are 300 mm deep, which was the depth of traditional networking equipment. As such, for adoption by a wide range of non-ICP network operators, including CSPs, compact modular platforms must support configurations that are 300 mm deep or less. For both 300-mm and 600-mm deployment environments, the depth of the system must include the bend radius of the connected cables so they are not sticking out into the aisle and could be accidentally knocked by personnel moving around the facility.

Figure 3: Ability to fit into 600-mm ETSI racks

Compact modular platforms are redefining service economics and raising the bar for network flexibility and agility. Their positive impact on business and operational models is resonating with all types of network operators. Their support for carrier-grade features will further accelerate their adoption by CSPs and broaden their application scope.