By Ayham Al-Banna, Tom Cloonan & Jeff Howe, ARRIS
The cable industry has achieved tremendous progress in offering high speed data since the first DOCSIS specification was released in 1997. MSOs had the dual goal of meeting customers’ demand for higher speeds and defending itself against competitive threats of speed wars with alternate technologies. As MSOs continue their network evolution, they are currently faced with no clear path since many options are available to augment their existing HFC networks.
For example, Figure 1 shows multiple potential evolutionary paths that the MSOs can select. The network architecture (e.g., I-CCAP/DAA/PON) is plotted against the topology which is presented here as the depth of the fiber in the network (e.g., HFC, FTTLA/FTTC, FTTT, and FTTH).
The transitions between different phases of the same architecture or moving from one architecture to another will depend on the priorities and conditions within an MSO. Different MSOs may select to transition to a particular alternative at different times and different locations. For example, current HFC networks using the normal practice of node splits going to Node+0 (N+0) may be able to continue that practice until year 2025. At the same time, some MSOs may choose to move to an N+0 architecture in the immediate future. Similarly, if an Extended Spectrum DOCSIS technology develops, MSOs may choose to move to FTTT architecture as soon as 2025 in order to access even higher speeds. Finally, it is assumed that most MSOs may eventually choose to migrate their networks to FTTH over the next decade or two.
Note that the capacities of all architectures (I-CCAP/DAA/PON) in an FTTH environment in the 2030 time frame are assumed to be similar (~400 Gbps+) because those architectures will likely leverage similar technologies at that time.
Given the large combinations of the various network architectures (I-CCAP/DAA/PON) shown in Figure 1 and different fiber depth topologies, selecting the appropriate architecture/topology transition path is not a trivial task. The challenge at hand is to understand the available technology enablers to assist in selecting the appropriate transition path. These technology enablers include node splitting, DAA, DOCSIS 3.1, spectrum management and reclamation, FTTx, Selective Subscriber Migration (SSM), extended spectrum DOCSIS, Full Duplex DOCSIS (FDX), and others. This paper will examine the forces that are driving MSOs to provide symmetric multi-Gigabit per second service, the technologies that will assist them in getting to those services, and the factors that will help guide them down the alternative migration paths that are available.