Networking

The ‘n’ stands for now

Rabih Dabbousi, Systems Engineer Director at Cisco GulfWithout delving too deeply into the past, we all remember the war-driving horror stories: buggy Wired Equivalent Privacy implementations, 802.11b technology that promised 10Mbps but barely delivered 5Mbps, 802.11g technology that promised 50Mbps but barely delivered 20Mbps, and prolonged standards battles over 802.11n.

Yes, Wi-Fi technology has been a tad disappointing. On the other hand, we have come to expect and appreciate wireless networks in our homes, coffee shops, airports and hotels. And employees, particularly younger ones, impatiently await the wireless workplace.

In our test of 802.11n access points and controllers, 802.11n technology delivered impressive data rates of 250Mbps per access point. In addition, it delivered solid performance numbers on latency and jitter, which means it can support such real-time applications as voice and video. The systems we tested had a variety of enterprise-level features, such as Power over Ethernet; dynamic radio-frequency control; QoS; and such security functions as intrusion prevention and detection, Wi-Fi Protected Access 2, and stateful firewalls.

Should you bite?

Rabih Dabbousi, Systems Engineer Director at Cisco Gulf, explains why the WLAN market share leader believes 802.11n is ready for prime time now. “802.11n wireless networks enhance the corporate network by combining the mobility and flexibility of wireless with the throughput and performance of wired networks. The corporate environment is going through a technology transformation and wireless access plays a crucial role in this transformation. With the emerging collaboration and interaction tools and applications such as High-Definition video conferencing, the need for reliable, high bandwidth coverage is more important than ever.”

Nicole Meier, Asst. Marketing Manager, D-Link Middle East, says, 802.11n will become the mainstream wireless technology this year. “The migration to 802.11n has already begun and 802.11n clients can now increasingly be found in laptops, notebooks and DMAs. The additional boost is expected to take shape with the soon to-be-launched, cost-efficient wireless N products from manufacturers like D-Link. As a consequence, the price gap between 11g and 11n products will shrink significantly so that 11n products will be obtainable at almost the same rates as 11g products, which – in turn – will facilitate the migration to 11n.”

The industry also believes the fact that 802.11n is yet to be ratified will not hinder adoption. “Customers are no more asking for fully ratified 802.11N standard products as the standard is taking too long and the available revisions of the standards are almost set for no more hardware changes, plus the fact that the industry has already produced millions of 802.11N devices at current revision,” says Ammar Enaya, Sales Director – Aruba Middle East and Africa.

Meier adds that people can invest in the technology without fear for a number of reasons. First of all, organizations like the Wi-Fi Alliance ensure multi-vendor interoperability by verifying that the systems from different manufacturers can be used within the same wireless infrastructure. If consumers are cautious to purchase only 802.11n products that are Draft 2.0 certified by the Wi-Fi Alliance, they simultaneously choose solutions with features that are most likely to be expected in the final standard. Secondly, the draft 2.0 features are very unlikely to change in a way that threatens the interoperability, she says.

When it comes to new construction, 802.11n should be the default choice. The choice gets tricky, however, when it comes to existing networks. If you already have some 802.11a/b/g/, keep in mind that running a mixed network will result in significantly reduced bandwidth. So what’s the best way to migrate from existing b/g infrastructure to 11n?

Cisco provides detailed migration services from existing wireless infrastructure, namely 802.11 a/b/g, to 802.11n. The corporate IT department follows the following steps with this detailed approach: Prepare, Plan, Design, Implement, Operate and Optimize. These steps involve both business and technical requirements development, network architecture reviews and design, site readiness assessment, Operational readiness assessment and a migration plan. Compatibility and co-location with a/b/g based networks is a must. Migrating to .n technologies doesn’t just end with access points. In addition to 802.11n access points, wireless controllers also need to support your newly deployed .n network. It is also essential to ensure end-user devices such as laptops, servers and smart phones support the new technology, says Dabboussi.

Enaya talks about other methods including an AP-overlay approach, which means the ‘Draft-n’ network would be planned as if there were no existing network, for optimum placement of the new APs. The old and new networks will be able to operate in parallel if care is taken with RF channel allocation, and when the new one is complete and all clients are 802.11n-capable, the old APs can be de-installed or abandoned. For this scheme, it is important that the radio planning and management algorithm of the WLAN can manage 802.11a, b, g and ‘Draft-n’ cells and APs simultaneously.

AP substitution in another option. In this model, existing APs are swapped one-for-one with new ‘Draft-n’ APs. If every AP is replaced with ‘Draft-n’, the resulting network will have plenty of capacity – resulting in perhaps a three-fold improvement, depending on the mix of 802.11a/g and ‘Draft-n’ clients – but will have more APs that would be strictly necessary. In most networks it will be possible to abandon some AP locations – either running an RF planning tool, or using RF self-calibration tools on a network mid-way through migration will give an indication of whether this is feasible. A network of mixed ‘Draft-n’ and 802.11a/g or even 802.11b APs can operate indefinitely: this is a possible solution where ‘Draft-n’ is important for classifying rogue APs but not for capacity or range considerations. Note that even though APs can be swapped at a location, the new ‘Draft-n’ AP may require different power and Ethernet connections.

No matter how you decide to roll it out, 802.11n is ready for the enterprise.

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