By Michael J. Emmendorfer, Thomas J. Cloonan, John Ulm, and Zoran Maricevic, ARRIS
This paper will define and extensively compare two (2) Classes of Access Architectures that will emerge this decade for Cable Networking. These two (2) Classes of Access Architecture may be referred to as Centralized Access Architecture (CAA) and Distributed Access Architecture (DAA). The use of Centralize Access Architecture (CAA) retains the MAC and PHY layer functions of the CMTS, Edge QAM, or CCAP in the headend or hub location. The use of Hybrid Fiber Coax (HFC), which utilizes Amplitude Modulation (AM) optical technology or analog optics, enables only Centralized Access Architecture.
However, a transition to digital optics for fiber to the node (FTTN) may enable either a Centralized Access Architecture (CAA) or a Distributed Access Architecture (DAA). In a Distributed Access Architecture (DAA) the MAC and PHY layers of the CMTS, Edge QAM, or CCAP may be split between headend and node devices or the MAC and PHY layer functions of the CMTS, Edge QAM, or CCAP may be placed entirely in the node, cabinet, or MDU location. As our industry considers digital optics between the headend and fiber node we need to understand the pros and cons of CAA and DAA.
Our industry has always placed the least amount of intelligence in the outside plant, thus keeping the intelligence together and only at the Headend and CPE locations (the bookends). The use of DAA fundamentally changes the style of access architecture cable has implemented since its inception.
Our industry is not aware of all these options, those that are aware from MSO to supplier are divided on which approach is best and why. We have compiled a complete evaluation criteria and side-by-side comparison of these six (6) different types Access Architecture, so that an MSO can make an informed decision.
Key Questions Examined in this Paper:
Some of the most often asked questions by cable industry forward-looking planners reflect the key challenges the industry is facing for this decade and beyond. Some of these challenges and questions include:
- Can Digital Fiber Coax (DFC) architectures maximize the coaxial segment revenue spectrum capacity?
- Can Digital Fiber Coax (DFC) architectures maximize the optical segment wavelength capacity?
- Can Digital Fiber Coax (DFC) architectures maximize facility space, power and cooling?
- Can Digital Fiber Coax (DFC) architectures maximize long links and facility consolidation?
- Can Digital Fiber Coax (DFC) architectures maximize the economics of OPEX and CAPEX?
This paper will seek to provide some visibility and answers to these questions and key challenges.