By John Chapman & Tong Liu, Ph.D., Cisco Systems Inc.
Not so long ago, the CMTS was all about the hardware, the chassis, the cable line cards with embedded CPU, memory and storage. It had long development cycles and expensive/lengthy processes for deployment and upgrade. The virtualization of the CMTS removed the need of the specialized hardware by providing the CMTS services in software running on generic servers. By doing so, it has greatly improved the efficiency of the CMTS hardware infrastructure and started the cloud native transformation of the CMTS software.
With the virtualization laying out the foundation, moving the CMTS to the cloud is a natural step forward to scale the CMTS beyond the on-premises physical servers. Cloud provides on-demand compute, memory and storage resources with high scalability, availability and security. It offers users the economies of scale and better cost efficiency with a pay-as-you-go cost model. It reduces the application development time and simplifies the deployment/upgrade processes by managing the underneath infrastructure and platform on behalf of the users.
CMTS cloudification is not just a rehosting effort, it is an optimization process that requires proper service decoupling and workload placement. The cloud computing services can be “resource-aware” or “serverless”. The resource-aware service, such as Amazon Elastic Compute Cloud (EC2), allows users to control the resource allocations and autoscaling at a relatively coarse granularity.
The serverless service, such as AWS Lambda or Amazon DynamoDB, fully manages the resources on behalf of the users with built-in fine-grained auto scaling capabilities. The geographical location of the cloud platform also matters as it impacts the network latency and the data transport cost. The distributed and inhomogeneous cloud environment presents an interesting and challenging problem for the cloudification of the CMTS.
In this paper, we explore the cloudification solutions for the CMTS. Following the introduction, we first overview the vCMTS structure in Section 2 and the public cloud infrastructure in Section 3. We then explain the cloudification motivations in Section 4 and describe the different architecture choices in Section 5. We examine the different cloud hosting options in Section 6 and explore the CMTS service placement strategies in Section 7. In section 8, we show an example for deploying the CMTS services on AWS. In Section 9, we explore how to take advantage of the serverless platform by converting the stateful DOCSIS processes into stateless functions. In Section 10, we discuss how to start the cloudification with a proof-of-concept (PoC) effort. In Section 11, we study how to deliver CMTS as a service by using CI/CD and the cloud powered multi-tenant architecture. Finally in Section 12, we conclude the paper.
To simplify the text and precisely describe the intended cloud entities, we use the Amazon Web Services (AWS) terminologies in this paper and provide links to AWS original definitions in the Reference Section. Similar terminologies and definitions can be easily found on other public cloud providers’ platforms such as Microsoft Azure, and Google Cloud platform.