Distributed Architectures and Converged Access Network

摘要

Cable operators are now actively converging video and data services into a common CCAP platform. And, as the usage of narrowcast services continues its seamlessly exponential growth, the evolution of the access network progresses relentlessly towards ever-smaller service groups. This results in a continuous growth of headend equipment, which will soon far exceed the capacity that facilities can support. Therefore, the above trends are now intractably linked to two additional evolutions: distribution of components of the access network, and virtualization of the core network functions. This paper will begin by outlining why and how the migration to a Distributed Architecture is necessary and beneficial. The paper will then expand into features that can be implemented with Distributed Architectures, and some of the resulting possibilities. Finally, this paper will discuss the topic of Virtualization, and how these additional evolutions relate to each other, as follows: 1. Present why Distributed Architectures are useful, which would cover the following key benefits: (1) HE density increase, which is becoming critical as MSOs are segmenting service groups more and more, including moving towards fiber deep and passive networks; (2) HFC network performance improvements by migrating to digital transport, especially as we move to DOCSIS 3.1 and would like to maximize the use of the higher order modulation rates that DOCSIS 3.1 offers; (3) Trunk fiber savings as we move to higher capacity digital links that can be muxed much more than analog links, and; (4) The ability to eventually virtualize the remaining upper layers of the CCAP. 2. Discuss features that could be implemented in Distributed Architectures, which are not possible with the current analog forward and digital return links, such as: (1) Broadcast capacity replication; (2) Multiple service groups per HE port; (3) Optical path redundancy. 3. Present the concept of Access Network Convergence, explaining how a single network could be used for various access technologies, which will cover: (1) The use of Ethernet switches in the node; (2) The use of multiple access technology modules in the node (RF, PON, etc.) 4. Finally, outline a network evolution strategy for services, and show how a Converged Access Network would make the evolution easier, including the Virtualization of Access Network Functions.