BROADBAND COMMUNITIES is the leading source of information on digital and broadband technologies for buildings and communities. Our editorial aims to accelerate the deployment of Fiber-To-The-Home and Fiber-To-The-Premises.
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10 | BROADBAND COMMUNITIES | www.broadbandcommunities.com | JULY 2016 MULTIFAMILY BROADBAND TECHNOLOGY Wi-Fi Over DOCSIS Managed Wi-Fi can now be implemented affordably over existing coax. By Jim Clark / Multifamily Broadband Council Technology Committee W i-Fi access is the de facto means to stay connected. People are disappointed when Wi-Fi is not available and often avoid places without Wi-Fi service. Wi-Fi has simply become "table stakes." For a multiple-dwelling-unit (MDU) or hospitality environment, the infrastructure cost for installing Wi-Fi services can be a significant barrier. Using a DOCSIS network with existing coax cabling may lower capital outlay, reduce time to market and lower day-to-day operation costs. Until recently, the cost of DOCSIS was a significant barrier for providers attempting to use coax cabling as an access medium. Since the early DOCSIS days, the industry focused on scaling up cable modem termination systems (CMTS) rather than offering granular solutions. In addition, off-the-shelf, residential-grade DOCSIS 3.0 cable modem gateways with built-in Wi-Fi are not ideal for use as access points where there is a high concentration of transient users. ese devices do not remove stale MAC addresses quickly enough for transient environments, and many cable modems have finite MAC address table limits. User limits can quickly be reached, preventing access to roaming Wi-Fi clients. is leaves a black hole until the table ages out – sometimes for hours – or else the cable modem must be reset to clear the MAC table. Recently, however, a number of DOCSIS "mini-CMTS," or distributed CMTS systems, have entered the market, making DOCSIS technology much more affordable – not only for high-speed internet services but also for managed Wi-Fi infrastructure. As the DOCSIS standard was crafted to support long cable distances, it can easily support campus distributions for spread-out properties. Coupling a DOCSIS 3.0 network with cable modem– enabled, managed Wi-Fi access points and an access point controller provides a recipe for distributed Wi-Fi at a generally lower cost of entry. is sets the stage for private cable operators that previously offered only video services to offer high-speed data or even triple-play services to a largely underserved population. In an example of MBC vendor collaboration, Ruckus recently worked with Harmonic Inc. to qualify a DOCSIS 3.0 solution as the access network for its C500 DOCSIS- enabled Access Point and SZ100 AP Controller. Ruckus wanted to validate that the recently available Broadcom-based products could support the requirements of managed Wi-Fi. It learned that the DOCSIS environment could sustain the necessary configuration for architectural approaches using Layer-3 tunneling and Layer-2 switching. ese combinations have been recently tested and certified at Harmonic and Ruckus facilities. THE FUTURE OF COAX Using existing coax has many advantages, including simplicity and replicability. e network access layer must allow for easily replicable, successful implementation across multiple properties. ough each site has unique construction and unique needs, a DOCSIS architecture provides relative consistency, making installations fast and easy to deploy and maintain. A coax network must be qualified like any other network, and the system must be swept and balanced to detect signal loss and unwanted noise. Repairing cracked or bent cables or corroded connectors may be necessary, but this usually costs far less per door than pulling new cable alternatives. e talent pool for deploying and maintaining DOCSIS networks is very well established. ere should be little argument that terminating coax cable is quick, and qualifying it is simple. In fact, many new construction builds are still pulling new coax cable. Providers of coax-based satellite video services can leverage DOCSIS technology on the same physical cable as the satellite video services. DIRECTV and DISH Network systems can peaceably coexist with DOCSIS 3.0 technology, and many DOCSIS systems are deployed this way. Can DOCSIS compete in the long run when the residential big guns are touting gigabit services? DOCSIS 3.1 Remote PHY technology, coming soon, is tailor-made for MDU settings. Multiple vendors are preparing to deliver low-cost deep fiber nodes that can easily support multi- gigabit services with DOCSIS 3.1 and 500 Mbps DOCSIS 3.0 services simultaneously. Vendors are demonstrating this technology today. So before writing off coax cabling, take another look at what you can do today with DOCSIS 3.0 distributed CMTS systems and know that you are well positioned for the future with DOCSIS 3.1. v Jim Clark, a Multifamily Broadband Council board member, serves on the MBC Technology Committee. He is senior systems engineer at Harmonic Inc. and can be reached at jim.clark@ harmonicinc.com. For more information about MBC, contact Valerie Sargent at 949-274-3434 or visit www.mfbroadband.org.