Mac of the Future: Networking

Glenn Fleishman
23 December, 2012
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The next two years promise faster short-range and medium-range wired and wireless networking, and zippier mobile connections.

What’s the point of these increasing speeds? Video, primarily. The name of the game is streaming or downloading high-definition video while leaving enough room for other activities such as file downloads and email.

Connecting devices

When Thunderbolt technology was still under development, Intel said that optical cabling would enable multiple-gigabits-per-second connections to displays, peripherals and networks, and that it would allow cords to run as far as 30m.

Apparently optical cabling was hard to produce and expensive, so Apple and Intel switched to copper wiring. That wiring still supported the Thunderbolt spec’s two channels of simultaneous bidirectional (‘full duplex’) 10Gbps data, but connections could
be no more than about 3m. Using wire also required the addition of chips to the cables, to handle signalling and to ensure backward compatibility with DisplayPort. The upside: Thunderbolt cords can pass up to 10 watts per device, more than double USB 3.0’s capacity.

In the future Thunderbolt will likely return to optical cables, which will allow for 30m runs. The intelligence could move from the cables into computers and mobile devices, making Thunderbolt cables cheaper. Alternatively, the cables will likely be able to supply just 4.5 watts or so per device. Our guess is that an optical update to Thunderbolt could arrive in Apple hardware within two years – but rather than replacing current Thunderbolt ports, it will have to come in the form of a new port on Apple’s pro models.

In the meantime, USB 3.0 is in all new Mac models (except the Mac Pro). At 5Gbps, USB 3.0 is not exactly slow, and compatible hardware is widely available. It meets many of the needs that Thunderbolt fills, aside from standard support of external displays. We predict that the scarcity and high costs of Thunderbolt-compatible hardware will keep USB 3.0 as the preferred choice for people who don’t need high-level performance.

While gigabit Ethernet is available in all Mac gear with Ethernet ports (except the AirPort Express and Apple TV), the 10Gbps flavour seems unlikely to come to Apple hardware soon, due to the cost of adapters and switches. Thunderbolt may be the solution. Apple already offers a Thunderbolt-to-gigabit-Ethernet adapter, and the company could sell a 10Gbps adapter. But outside of server rooms and data centres, gigabit Ethernet will likely remain the default choice.

Through the ether

In all Apple devices with wireless capabilities, 802.11n Wi-Fi is the default. Newer 802.11n devices, such as the iPhone 5, boost speeds by supporting both the 2.4GHz and 5GHz frequency bands. But wireless networking will soon get even faster thanks to the advent of two new technologies: 802.11ac (which is an update to 802.11n) and 802.11ad (for in-room super-high-speed streaming).

The 802.11ac update, already shipping in equipment from some vendors even though the standard is not yet finalised, can boost networking speed to a raw rate of over 1Gbps in particular cases. While 802.11n tops out at 450Mbps in Apple equipment and similar networking gear, comparable 802.11ac base stations will have a minimum top rate of 867Mbps.

Since 802.11ac works only in the 5GHz band, 802.11n will remain the standard for the crowded 2.4GHz band. In addition, much of 802.11ac’s performance improvements will be realised only in certain circumstances or when you’re using advanced hardware; the greatest speed boosts will be apparent in enterprises, on academic campuses and at large-scale hotspots such as convention centres and airports.

Despite those limitations, Apple could add a preliminary version of 802.11ac to its base stations as soon as the next major refresh of the product line. Adding 802.11ac to mobile devices might not enhance their speed much, but it would improve efficiency: A base station with that standard built in can simultaneously and separately communicate with multiple simpler 802.11ac devices (those that can’t send multiple data streams at once) instead of interacting round-robin among them.

Although 802.11ac will eventually become part of the certified Wi-Fi spec, the 802.11ad standard is something else altogether. It offers four channels, over each of which data can race at rates up to 7Gbps. But such speeds are available only over distances of no more than about 9m. That’s because it uses the 60GHz band, and signals at those frequencies can’t penetrate objects well.

For that reason, 802.11ad’s main uses will be for rapid transfer of large files or for streaming uncompressed high-definition video. Normally, high- def video is stored in compressed form on hard drives, DVDs, or Blu-ray; when you stream video over the internet, it travels in compressed form, too.

Once your device receives the data, it decompresses it for playback. Repeated compression and decompression can compromise the video quality. If you can send video uncompressed – which 802.11ad enables – you can watch it at the highest possible quality.

The ideal convergence will be base stations and adapters that incorporate 802.11n for 2.4GHz and 5GHz, 802.11ac for 5GHz, and 802.11ad for 60GHz, automatically switching as necessary to the best medium for the task or the reception quality. Some chipmakers have already announced plans to create sets of chips for just that purpose – but don’t expect to see 802.11ad before 2014.

Faster mobility

LTE (Long Term Evolution), a 4G mobile broadband standard that cellular operators are deploying around the world, is all the rage. But the LTE currently being used is a low-speed version of the spec.

When LTE was first being devised as a thorough overhaul to the evolutionary approach of GSM- derived 3G and 4G networks a few years ago, the developers knew that an even faster LTE would be possible. That version, now called LTE Advanced, promises speeds up to 3Gbps with fixed devices and hundreds of megabits per second for in-motion receivers traveling rapidly, as in cars and trains.

Like LTE, LTE Advanced can use frequency channels of many different widths, in contrast to the hard limits of 3G and 4G networking technology. LTE Advanced goes even further, and can aggregate channels that are spread out, as opposed to continuous frequencies, enabling a carrier to assemble bandwidth at lower cost.


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