Enterprise LANs, service providers and other network operators are experiencing a sharp rise in the demand for wireless connectivity driven by the growing use of mobile devices. The wireless half of the solution is to deploy high-capacity Wi-Fi access points, which support the new IEEE 802.11ac Wave-2 standard.
Creating a truly-mobile-centric network also requires a backhaul network capable of supporting the access points’ full >1 Gbps capacity.
The Rise of the Mobile-Centric Network
It’s sometimes said that a wireless network is only as good as the wires behind it. Both enterprise and carrier networks are becoming painfully aware of this truism as their wireless networks, and their wired backhaul infrastructures, struggle to accommodate the growing number of laptops, tablets, and other handheld devices carried by an increasingly-mobile society. In fact, many of the public and private LANs we encounter every day are facing an explosive growth in wireless data traffic. To illustrate this point, let’s look at one of the departure lounges at your regional airport.
If we were at Gate 10 on a holiday weekend back in 2001, we’d probably find a small group of road warriors in the crowd hunched over their laptops. They’re working on whatever files they have on their hard drives since Wi-Fi service is only beginning to become available and there’s nowhere to plug in a modem. Meanwhile, most of your other fellow travelers read books or newspapers.
By 2005, the number of laptops had grown a bit, and there were quite a few people listening to music on their MP3 players or one of those sleek new iPods. You may have Wi-Fi access but if you do, you have to pay for the slow-as-molasses service.
A decade later, the lounge’s drab décor hasn’t changed, but the technology in the passengers’ hands certainly has. Nearly everyone you encounter in 2105 is packing multiple mobile devices, all of which have wireless Internet access. More than half your fellow passengers are working on their Wi-Fi-connected laptops, some of whom are also watching movies via streaming multimedia. Many of the folks not sporting laptops, are carrying smartphones, tablets, or other mobile IoT devices that require access to the Internet. With most of the 50-200 people at each gate, all acting like huge bandwidth sinks, the need for lots of high-capacity wireless on-ramps becomes obvious.
802.11ac – It’s Not Your Dad’s Wi-Fi
To accommodate the growing load, network managers are already beginning to deploy a new generation of Wi-Fi access points which can support more users per access point, at dramatically higher data rates. This equipment is based on the IEEE’s 802.11ac Wave 2 Wi-Fi standard. Products based on the earlier 802.11ac Wave 1 which defines a set of advanced wireless techniques, including MIMO signal processing to deliver more capacity which are well-suited for consumer/residential applications are already commonly available.
The 802.11ac Wave 2 standard aims at enterprise-class applications by further boosting both the raw capacity and the numbers of users the access point can support in an efficient manner. It builds on Wave 1 technology with the addition of sever additional capabilities, including beam forming/steering and channel optimization which allow it to support up to eight simultaneous data streams, with each running at a theoretical maximum of 866 Mbps.
The Wires behind the Wireless
The first Wave 2-capable Wi-Fi access points should be commercially available in early 2015. It won’t be long after that before enterprise LANs, as well as public and commercial data infrastructures, begin to deploy them. Even it takes a year or two beyond analyst’s predicted date of 2017 when 2/3 of business network traffic originates from a wireless endpoint, the build-out of a wired infrastructure to support the growing traffic load must begin as soon as possible.
Each of the dozens (in some cases, hundreds) of the high-capacity Wi-Fi access points deployed throughout a network will require an equally fast backhaul connection. The Category-5e/6 cabling used in most enterprise cable plants is only rated for Gigabit Ethernet, while Wave 2 access points can support traffic rates far in excess of 1 Gbps. As a result, network operators won’t be able to enjoy the full benefits of their wireless network until they upgrade or replace the large installed base of copper-based Gigabit Ethernet ports.
Until recently, one of the few things network managers can do to smooth out this gigantic “speed bump” was to pull new cabling, but this can be very expensive. NBASE-T estimates that adding a single new cable run costs roughly $300, not counting line card upgrades. This translates into hundreds of thousands of dollars for a campus-wide upgrade, since Cat5e and Cat6 cabling comprise nearly 100 percent of the installed cable base in enterprises globally.
Although it’s also possible to achieve faster data rates using link aggregation techniques which combine two or more GbE connections into a virtual multi-Gigabit stream, this method requires specialized, potentially costly, hardware and has its own set of implementation and maintenance challenges.
Since many switches and routers can accept new line cards that support higher speeds, the industry has turned its attention towards technologies, which can support multi-Gigabit Ethernet connections across the existing Cat5e/Cat6 cable plant. An ideal “no-forklift” solution would make it easy to support any GbE-compliant network topology.
It would also work seamlessly with existing management protocols, precisely like the Gigabit Ethernet links found in the “pizza box” hubs already lurking within network wiring closets. Since it would be inexpensive enough for use in commodity-grade networking products and line card upgrades for existing GbE equipment, it would need to be power-optimized. Low-power operation is necessary to insure the products it’s used in can operate in uncontrolled environments, including the torrid confines of tightly-packed equipment closets.
NBASE-T: “It’s Just Faster Ethernet”
Nearly every must-have mentioned above will be addressed by the NBASE-T Alliance, which was formed in 2014 by a group of industry leaders with the objective of providing a platform to facilitate wide deployment of solutions for 802.11ac backhaul.
The alliance’s mission is to accelerate adoption of NBASE-T products and technology, and alliance members are working closely with IEEE to create and release a standard based on the technology. In the meantime, the alliance offers a specification that is already enabling its member companies to deploy products and technologies based on NBASE-T.
NBASE-T technology was created to enable network upgrades without replacing existing 1 GbE-capable wiring plants. The proposed specification includes the requirements for PHY-layer devices capable of supporting data transmission across Category-5e (or better) UTP cabling at speeds of 2.5 Gbps (2.5 GBASE-T) and 5 Gbps (5 GBASE-T). The NBASE-T design includes a Media-Independent Interface (MII) that’s compatible with GbE MACs. This allows it to be quickly and seamlessly integrated into existing network designs, or used to create switching solutions that enable quick and cost-effective upgrades to existing installations.
The technology will enable development of networking equipment that can convert existing GbE ports into multi-Gigabit backhaul links for 802.11ac access points and other mid-capacity (<10 Gbps) applications. NBASE-T works seamlessly with other Ethernet technologies, including the IEEE 1588 Precision Time Protocol (PTP). The ability to carry the network timing information used by cellular networks will allow NBASE-T to dramatically expand the capacity of Ethernet technology-based backhaul links used in modern, small-cell clusters.
Network operators are beginning to deploy Wi-Fi access points which support the 802.11.ac Wave 2 standard in order to meet an increasingly-mobile population’s growing demand for wireless connectivity. NBASE-T will play an important role in these mobile-centric networks, beginning with creating high-capacity backhaul links for their Wave 2 access points using their existing Cat-5e UTP cabling. The 2.5Gbps and 5Gbps Ethernet data rates proposed by the NBASE-T will also enable equipment manufacturers to create products that offer network operators:
- Forklift-free incremental upgrades to existing cable plants with minimal changes to network configuration.
- Cost-effective upgrades to many GbE networking products.
- Low-power consumption.
- Easy configurability for new and upgraded equipment.
NBASE-T products and technology are finding their way into semiconductors, and networking products which use them. Some of the places where NBASE-T will enable the wires behind the wireless network include enterprises, SMEs/SMBs, airports, universities, hospitals, conference centers and other public areas where Wi-Fi is as much a must-have service as air conditioning. Thanks to NBASE-T’s ability to work with IEEE’s PTP remote timing protocol, it’s also expected to play a key role in the upgrade and build-out of Ethernet-based backhaul links used in modern small-cell networks.
About the Author
Larry O’Connell is a product marketing director at Vitesse Semiconductor with nearly two decades of experience in the networking and communications industries. Mr. O’Connell holds a bachelor of science in mechanical engineering from Tufts University and an MBA from Cornell University.