No Two Are Alike


Tackling the MDU Challenge With G.Fast 

Remember the days when you were happy to have a second line for Internet connectivity only to enjoy blazing fast data speeds of 56 Kbps? Funny how things have changed — or have they? Today it’s all about ultra-broadband services which in turn are creating a virtual firestorm of FTTH deployments around the world as operators race to quench consumers’ thirst for greater bandwidth and faster data speeds.

By the end of 2015, over 775 million homes will enjoy ultra-broadband services — great news for those of us living in areas that operators are able to offer ultra-broadband speeds. But what about those of us that live in areas that are too difficult or complex to reach with fiber, such as multiple dwelling units (MDUs), which can pose special challenges for operators? Much like snowflakes, no 2 MDUs are ever the same, requiring operators to evaluate and address each building or apartment individually. With more than 6001 million (or estimated 50 percent) of us living in MDUs worldwide, this can be a significant hill for operators to climb, and could create the potential for a new digital divide. However, in the highly competitive race to secure MDU subscribers, many of today’s global operator’s continue to search for a solution.

While Fiber-to-the-home (FTTH) is the preferred method for extending ultra-broadband access, it’s not always the option that gets implemented in MDUs due to a number of deployment challenges:

Building infrastructure: With more than 83% of MDUs built before 2000 and more than 50% built before 1980 in the US alone, operators are often faced with legacy infrastructure that was designed before the birth of the Internet. Upgrading to fiber is an option but can be costly and time-consuming.

Variation in building types: MDUs range from small row houses to large high-rise buildings, which are rarely alike and always require creative approaches from the installer. Larger buildings with more than 100 living units are seen as low hanging fruit by many operators. The hope is to capture a large number of subscribers. However, these MDUs represent a small percentage — approximately 2% — of the overall MDUs out there today. The real coverage challenge is in addressing the over 70% of MDUs that accommodate 4 families or fewer.2 In these scenarios, the snowflake factor is critical.

Gaining access: Operators must deal with the logistical challenge associated with getting permission to access each individual building or living unit to install equipment and fiber which can vary widely between building owner, city, municipality geography and subscriber.

To effectively address these challenges, operators must be able to draw upon a deep tool kit of FTTx techniques and technologies that can address the ultra-broadband needs of each customer, all of which can be complex, time-consuming, and expensive. Many access technologies have been used over the years to overcome these challenges but none of them held the promise of Considered by many as an enabler for FTTH deployments, is ideally suited for an MDU environment.

MDU Technologies for the Twisted Pair

Ethernet is a viable alternative for operators lucky enough to have access to CAT5 cable or better which is capable of delivering 1 Gbps synchronous to each living unit.

VDSL2 has long been used in MDUs to address the legacy copper cable challenge. Now with vectoring, VDSL2 can deliver aggregate bitrates in excess of 150 Mbps (100 Mbps+ downstream) and with features like G.inp, which adds stability with resistance to impulse noise that can be generated within the MDU. As a result, it remains a solid option for addressing the challenges associated with the MDU. offers the best of both worlds and more. It is able to run on legacy copper infrastructure like VDSL2 while supporting fiber-like bitrates over very short loops. Since it was designed for use in the outside plant, it includes a number of protections against noise and other issues that could impair performance, all features that Ethernet lacks. (See Figure 1.)

Figure 1. vs VDSL

Figure 1. vs VDSL

So why is so effective in helping operators address the MDU challenge? It comes down to physics. By extending the frequency range — up to 106MHz — over which the broadband signals travel, can deliver 100s of Mbps (up to 1 Gbps) of capacity to customers using the same copper that once delivered 56 Kbps. However, with higher frequencies come shorter distances over which those data speeds can be sustained. Yet, in a MDU application where copper distances rarely surpass 200 meters, is quickly becoming the choice solution for operators, providing a more effective and efficient way to deliver competitive ultra-broadband and next-generation services to older buildings once owned by the cable providers.

Overcoming the Snowflake Factor With G.Fast

The wide variation in MDU age and construction requires an equally wide variety of deployment solutions. is ideally suited to this challenging environment. Since serves only short copper loops, access devices need to be small, serving fewer subscribers than ever before. Commonly called micro-nodes, these discreet and flexible devices can be deployed in any location that is conveniently close to users and cost-
effective for the service provider. As Figure 2 illustrates, micro-nodes address the snowflake factor with a variety of form factors:

Figure 2. Micro-node MDU deployment scenarios

Figure 2. Micro-node MDU deployment scenarios

Sealed Small form factor, sealed micro-nodes offer deploy-anywhere flexibility. They can be used outside a small MDU where no equipment room is available. They are inherently tamperproof for indoor applications where no secure equipment room is available. And since they are passively cooled, they lack the fan noise of traditional rack mount solutions.

ONTFor FTTH operators, micro-nodes are simply another ONT choice. Single or multi-port ONTs can be tactically deployed where running fiber all the way to the living unit is not practical. Fiber-to-the-front-door (FTTfd) ONTs can reduce costs and effort by supporting reverse power and subscriber self-installation. They bring the speed of fiber to customer’s front doors, and avoid the cost of rewiring living units. FTTfd ONTs can be installed outside the residence at a time that is convenient for the operator, and automatically activated when the subscriber self-installs the CPE.

Bridging the MDU Divide

Creating an onramp to 100+ megabit and even gigabit speeds, is beginning to help operators bridge the MDU divide and deliver ultra-broadband access to customers for a fraction of the price, disruption, and time associated with fiber alone. Providing a solution for virtually every MDU scenario, potential barriers once tied to a building’s size, location, or infrastructure have faded away, creating value where little may have existed before.

“Many service providers struggle with the logistics and economic challenge of deploying fiber within MDU environments because of difficult access and notoriously high churn,” said Teresa Mastrangelo, senior analyst at Heavy Reading. “ has emerged as an ideal technology for bridging this gap by matching the ability to deliver near gigabit speeds over the short copper loops found in most MDU environments with the reality that overlaying the twisted copper pair infrastructure in these buildings can be difficult and expensive. Many think of MDUs as a niche market, but they actually represent the majority of subscribers worldwide.” 

Sources: 1. TMCNet 2012 “Overcoming the Challenges of Fiber Deployment in Multi-Dwelling Units” by Linnea M. Wilkes, TMCnet Special Guest, December 10, 2012. 2. NMHC tabulations of 2012 Rental Housing Finance Survey microdata, US Census Bureau. Updated 8/201


About Author

Keith Russell is Product Marketing Manager, responsible for global marketing activities for Alcatel-Lucent’s Fixed Networks Division, focusing on market strategy, product planning, and campaign management for FTTx access solutions. He also spent 5 years at Alcatel-Lucent as a business manager focused on the North American Independent Telco Market. He has more than 20 years of experience in fixed access and the Telecommunications industry. For more information, please email or visit

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