Our Retail Networks
The Columbus access network is comprised of two discrete physical layers. A Hybrid Fiber Coax (HFC) network is used for residential triple play services (video, voice and data), and a direct fiber network for Ethernet and TDM based business services.
The HFC access network is designed using a completely passive N + 0 architecture with a maximum of 100 homes per node. In order to provide for significant downstream and upstream growth capacity, the homes-per-node ratio is strictly enforced even in high-density areas. In addition, the Columbus architecture does not allow any active elements beyond the optical node and this is also independent of home density. The downstream passive RF design is maintained at 870 MHz and the entire video payload is 100% digital. All signal levels at the home are designed to allow for a minimum of 9 dB of headroom with the entire 870 MHz bandwidth fully utilized. The CMTS is designed to allow for a maximum of 400 homes passed per downstream and the upstream is limited to a maximum of 200 homes passed. This provides for a DOCSIS 3 access system capacity of 5.2 Gb/s per 400 homes passed downstream and 120 Mb/s per wavelength for 200 homes passed on the upstream.
In addition to the HFC network, Columbus also employs Fiber-to-the-Home (“FTTH”) technologies. The FTTH access networks utilize GEPON with DOCSIS provisioning. The consumer is provided a completely transparent experience for their services whether delivered via HFC or FTTH. The FTTH access networks can use either the existing RF video feed or Columbus’ state-of-the-art multiscreen IPTV delivery platform.
The direct fiber network provides Ethernet or TDM services of either point-to-point or complete ring network topologies. Consolidation points (hubs/POPs) are installed throughout the network to allow for greater reliability and network scalability. IP or native TDM services operate independently over the same core and access fiber network. Ethernet services are supported on a redundant IP/MPLS core with bandwidth scaling from 1Mb/s to 10Gb/s. TDM services are supported from sub T1 to fully SONET/SDH compliant OC192/STM-64 connectivity. The core fiber network is designed with high fiber count capacity allowing for significant system growth and also employs DWDM with photonic cross-connects to further enhance reliability and allows engineers to re-route traffic in the optical domain.
Both access network topologies are supported by high speed self- healing Metro layers linking a single Head End with all remote hubs and data POPs. All metro layer networks are designed with fully redundant facilities such as dual generators, multiple fiber routes, dual fiber entrances, and dual DC power plants. In each country, the video payload is derived at a single fully digital head end and the payload is transported over the metro network to individual hub sites serving specific access areas. All mission critical components in the head end and remote hub facilities are powered with redundant DC power plants. Each of the metro core facilities are hardened and protected against failure modes by using fire suppression, ground rings, N+1 redundant air conditioning and UPS systems. In addition, all core routing/switching, VOIP switches, back office and network support servers, and TDM transport electronics are fully redundant and are sourced from recognized carrier grade technology partners.