A major challenge faced by cable operators and other service providers is how to ferry signals around homes crammed with more – and increasingly sophisticated and throughput hungry – networked electronic equipment.
Several groups are working on this issue, including HomePNA, HomePlug and the Multimedia over Coax Alliance, which released a new version of its spec in October. Editor’s note: The MoCA Technology Conference on Nov. 14-15 occurred too late for press time for this article. Look for coverage of it next month and on our Web site, www.cable360.net/ct. Also see the sidebar for MoCA background and the conference agenda.
The sector is in its infancy since the need for sophisticated home networking protocols is relatively recent. It promises to be a hot topic. For one thing, money can be made from the networking services themselves. Perhaps more significantly, application and service providers signing onto the winning spec figure to be able to sell their products and services more efficiently.
HomePNA’s major – and to this point only public – proponent is AT&T, which uses it in the U-Verse project. Rich Nesin, the vice president of marketing for HomePNA chip set maker CopperGate said that the technology is standard in AT&T’s U-verse offering, which, as of the end of the third quarter, stood at 126,000 subscribers. The only announced large-scale rollout of MoCA is in Verizon‘s FiOS fiber-to-the-home initiative, which is in well over 1 million homes. No other users are publicly acknowledged by either MoCA or HomePNA, but the sense is that both are scrambling to pick up backers.
The prospects for MoCA in the cable industry are good. It’s also lucky, since HomePNA’s use of the 5-42 MHz frequency inhabited by cable’s return path effectively puts that spec off limits to operators. There are no immediate plans for a workaround that would enable operators to use HomePNA, Nesin said.
Comcast and Cox are "promoter" members of MoCA, which is its highest designation. Indeed, Comcast’s Charlie Cerino is the group’s president. It is worthy of note, however, that no other cable companies appear on MoCA’s Web site, www.mocalliance.org. The consortium was formed in 2003. "I wouldn’t draw conclusions from the member list who will be deploying, but I can’t offer specifics," said Anton Monk, a MoCA board member and VP communications technology and co-founder of Entropic, a vendor of chipsets.
Time Warner Cable spokesman Mark Harrod said that the operator plans to use the MoCA specification when it rolls out its next generation of multimedia services, which is expected next year. The operator, which currently uses 802.11g to distribute signals within subscriber homes, has no plans to join the consortium, however. Harrod would not comment on why the operator would support the technology without joining the group. Comcast would not comment on its plans and did not respond to a request for comment.
HomePNA, MoCA, 802.11a, b and g, the HomePlug Alliance and other home networking schemes operate at the physical and media access control (MAC) layer, said CableLabs CTO Ralph Brown. CableLabs’ CableHome initiative, he said, provides higher level residential gateway management functions.
The two are related, of course. The physical/MAC layer protocol being used – MoCA or others – links to CableHome through network interface blocks (NIBs) in the simple network management protocol (SNMP) layer that manages the CableLabs spec. The SNMP NIB connecting the two is largely the same no matter which of the physical layer home networking schemes is used. However, the NIB can accommodate unique features, such as Wired Equivalency Protocol or Wi-Fi Protected Access (WEP and WPA) security in 802.11g, Brown said. Three changes in 1.1 The new MoCA spec features three upgrades, Monk said: An increase in throughput, a doubling of the number of outlets in the home that can be supported, and a way to prioritize application delivery to favor the service providers’ offerings.
The usable data rate has jumped from 100 Mbps to 175 Mbps. It should be noted, Monk said, that both numbers represent data rate that actually is available to devices and applications, not theoretical figures.
Perhaps even more important, Monk said, is that testing on the older 1.0 standard indicated that that data rate was available at 97 percent of the outlets in the home. The newer spec maintains that level of delivery while increasing throughput by tweaking the approach to the MAC layer. The MAC does this through packet aggregation, which enables groups with similar packets – those carrying the same content and headed to the same destination – to be grouped together. They can be pushed through with far less overhead than the previous version, Monk said. This increases the potential payload size.
MoCA 1.1 doubles the number of delivery points – Monk refers to them as outlets – that can be supported to 16. The biggest challenge in supporting more nodes is navigating the complex echo problems that characterize in-home coaxial connections. This, Monk said, is done in the MoCA spec by using pre-equalization to smooth out the differences in the echo profiles between outlets. The use of bit-loaded orthogonal frequency division multiplexing (OFDM) enables this to be done in a fine-grained manner. MoCA 1.1 increases the speed at which link characterizations can be done to the extent that 16 outlets can be supported.
Last – but certainly not least – is an expanded prioritization scheme. In fact, Monk said, the most significant change from MoCA 1.0 to 1.1 is parameterized quality of service (QoS).
The idea is that in the emerging world, content will enter the home from a variety of sources. Service providers, Monk said, are worried that such high contention will interfere with delivery of their applications.
Existing in-home QoS approaches prioritize traffic. This is not enough to assuage service providers. Parameterized QoS takes the important step of guaranteeing capacity to applications designated by the service provider (which figures usually to be those it offers). The data rate is not pinned up, however: If the service provider’s prioritized application is not using its allotment at a given point in time, the capacity is available to other applications. Carl Weinschenk is a contributor to Communications Technology. Reach him at firstname.lastname@example.org. Sidebar: All About MoCA The Multimedia over Coax Alliance is an open, industry driven initiative promoting distribution of digital video and entertainment through existing coaxial cable in the home. MoCA technology provides the backbone for whole home entertainment networks of multiple wired and wireless products.
The goal of MoCA is to create specifications and certify products that will tap into the unused capacity available on the in-home coax without the need for new connections, wiring, point of entry devices or truck rolls. It is anticipated that the first MoCA enabled products will be released within the next year.
The annual MoCA Technology Conference is scheduled for Nov. 14-15 in Austin, Texas, at the Renaissance Austin. Scheduled speakers include Tony Werner, Comcast; Mark Wegleitner, Verizon, and Steve Silva, Cisco/Linksys. Charlie Cerino, MoCA president, and Dr. Anton Monk, MoCA CTO, will moderate both days.
Scheduled presentations include The Future of the Network is in the Home; Service Provider to End Consumer: Getting From Here to There; Emergence of the Connected Digital Home; Verizon’s Access and Home Strategy; and MoCA … Its Role in the Home and the Larger Network.
Scheduled panels include From the Press Box; How Will This Play in Peoria?; MoCA Protocols – What exactly Is this MoCA Thing?; and In Pursuit of Convergence – The Home Media Gateway.