CES 2010: The Practical Networking Shortcomings Of Phone Lines And Coax (And For That Matter, Cat 5e)

One of a series of planned posts from the 2010 Consumer Electronics Show…

It never fails. I write something even slightly critical of HomePNA, MoCA, and/or the HomeGrid Forum whose ITU-T G.hn standard unites them, and inevitably within 24 hours my inbox has filled with angry diatribes from technology supporters who accuse me of ignorance, editorial bias, or worse. Sigh. So predictable. So tiresome.

To be clear, I’ve followed both technologies (along with DS2, whose powerline approach currently forms the third member of the G.hn triumvirate) for a number of years now. Last week at CES, in fact, I dropped by the booths and otherwise met with a number of companies associated with these technologies. To accuse me of ignorance is naive. To accuse me of bias is…biased (and rigid). However, to set the record straight and lay out all my cards on the table, I’ve decided to document the big-picture data that informs my opinion. Reader feedback is, as always, welcome:

• Coax-based networking is predominantly a North America-centric technology, due to its tight linkage with cable and satellite television service.
• Phoneline-based networking is slow. That’s one of the reasons why HomePNA v3.1 optionally instead runs over coax cable.
• Both technologies are problematic with any structure built directly on top of a concrete slab, due to the consequent difficulty of room-to-room cable routing (since there’s no crawl space or basement that can be leveraged). This shortcoming is particularly evident if the coax or phone line topology isn’t integral to the initial residence construction.
• Due in part to the construction issues mentioned above, and more generally to distaste with crawling around in dirty, dusty environments and drilling holes in walls and floors, neither technology receives notable consumer interest regarding residence retrofits to add network connections. Yes, yes, I know there are plenty of engineering readers out there who think nothing of tackling such a chore. But as I’ve gently suggested any number of times, you by far represent the mass-market minority. And anyway, if you’re going to go to all that trouble, why not just run Cat 5e cable instead?
• The bulk of the market for HomePNA and MoCA, therefore, is in respectively selling adapters to telecom and cable-or-satellite television service providers, since these customers have to run the requisite cable anyway. But this means…
• …that wired networking spurs will only extend to a few rooms in a given residence, and to locations in those rooms where although telephone or television service may be optimal, networking support may not be ideal. The allure of either HomePNA or MoCA greatly diminishes if you subsequently need to tether Ethernet cable from the coax or telephone wall jack to where you really need network connectivity, or if you instead need to rely on oft-problematic Wi-Fi for intra- and/or inter-room network service.
• Contrast the above points to a powerline-based wired backbone approach. How many power outlets on average exist in each room of your home? In fact, are there any rooms in your home that don’t have at least one power outlet? And isn’t it a given that a powerline-delivered network ‘dial tone’ would inherently be in close proximity to the electrical outlet that powers the networking gear?

Don’t get me wrong. Powerline networking, as my innumerable ’scars’ from test-driving the technology for many years and many generations, is by no means a panacea. It exhibits, among other things:

• An inability to run ‘through’ surge protectors and UPSs
• Susceptibility to degradation-to-disconnection caused by premises power loss, until the consumer manually unplugs and plugs back in all of the adapters
• Sensitivity to power grid noise such as that created by motors (refrigerators, ventilation fans, air conditioners), heat sources (hair dryers, furnaces), and AC/DC converters
• Irregular reliability across time and temperature, and
• Difficulty in ‘jumping’ across the phases of the incoming 220V source feed at the circuit breaker box, thereby restricting the number of usable outlets in the house

However, while I’m not at all underestimating the service provider market where HomePNA and MoCA currently reign supreme, whenever a consumer wants to broaden his or her network ‘footprint’ and for some reason isn’t able to do so via Wi-Fi, powerline networking’s ease of adoption gives it a compelling ‘leg up’ on alternative wireline technologies. Including, yes, Cat 5e cable.

Have a good weekend, all!