March 28, 2008

Architecting a Reliable Wireless Network

Few question that the age of mobility is upon us. The emergence of a global economy is facilitated by the basic mobility of goods, services and people. For many, the idea of mobility has become second nature. Of course, the structures for mobility – transportation, logistics, infrastructure – must be robust and reliable lest the mobile quickly become immobile.

Given this, it is critical that the wireless industry focus R&D on improving network performance and reliability. What makes this challenging is the need to do this from applications, to the network, and very importantly, to a wide range of mobile devices. To achieve this, businesses should focus on the following key areas when designing a highly available wireless network:

• Managing the growth in wireless devices – Managing the growth and diversity of devices connecting to the network requires a continued focus on device compatibility and testing. Through its Cisco Compatible Extensions program, Cisco works with leading Wi-Fi silicon manufacturers to ensure simple, secure connections for a broad range of mobile devices. Another key need is ongoing interoperability testing and validation. While not widely known, Cisco has a very robust program in place, called Assurewave, to achieve just this.

• RF management is critical – IT should not underestimate the importance of pushing the envelope in radio development and optimization. In the wireless industry, providers either integrate off-the-shelf radio technology, or internally develop radios. Only by internally developing its own radios and antennas can a provider truly deliver a high performance access point. A robust solution combines radio expertise with software excellence so IT can benefit from dynamic radio resource management capabilities. This removes the complexity of management while ensuring an adaptive network capable of responding to environmental changes including changes in user and device location and density.

• Spectrum Intelligence – It is difficult to place heavy reliability requirements on wireless networks without clear visibility into the RF spectrum. Comprehensive spectrum intelligence solutions are critical to provide the intelligence to classify, locate and mitigate RF interference, including from non Wi-Fi sources such as microwave ovens, cordless phones and Bluetooth.

• System Unification – For performance and simplicity, the wireless network must be unified with the wired network. In this way, IT can leverage common services and provide the processing horsepower needed to support the breadth of mobility applications being demanded by users, while achieving efficiencies in power and resource consumption.

• Intuitive Management – By deploying a comprehensive management solution, IT can obtain the requisite diagnostics and reports on system health before issues become service impacting. The wireless management solution must have proactive tools that help IT optimize the wireless deployment and on going operations.

Only by deploying a wireless infrastructure designed to meet the reliability needs of the most stringent environments can IT enable the business to take advantage of emerging mobility solutions.

Cisco has led the industry in the development of industry specific solutions like mobile care solutions for healthcare and in-store mobility solutions for retail. These are delivered over next generation, high performance wireless networks like 802.11n. With a significant part of its R&D invested in developing highly available wireless networks, Cisco continues to turn the immobile into the mobile, and keep them there.

Posted by Chris Kozup at 01:00 PM Permalink | Comments (0) | TrackBacks (0)

March 24, 2008

Responding to CRN's 802.11n Testing

CRN recently published an article profiling 802.11n performance testing of the Aironet 1250 Series access point. The article titled “Where’s Cisco with Wireless N?” (http://www.crn.com/networking/206905063#community) profiles the results of their testing of Cisco’s 802.11n solution. The article was part of a larger story testing 802.11n products including Meru and Ruckus.

Cisco declined to participate in the CRN product review due to basic differences in product testing methodology. Cisco asserts that the review of its 802.11n access point as presented by CRN misses some of the basic principles of product testing and as such is inconclusive on many levels. Firstly, CRN tested a product that was operating with an early version of software. As with any new hardware, users should seek the latest software to ensure optimal performance. The code for Cisco’s 802.11n access point has evolved quickly and the version used by CRN had already been through 4 subsequent releases. The most recent product code is always available for download from the Cisco website – a point that was overlooked by the CRN staff.

Secondly, CRN tested the access point with several client devices that were using old device drivers and had not been Wi-Fi Certified for the 802.11n draft 2.0 standard. In fact, the Toshiba Portg M700-S7002 – the only device to have Wi-Fi 802.11n certification – was tested using drivers from early 2007, predating any 802.11n Wi-Fi certification. Wi-Fi certification is imperative when benchmarking performance results. The refusal to update device drivers clearly added to incompatibilities and limited performance results. Furthermore, CRN tested only the 2.4GHz radio with little detail given as to the use of 20-MHz or 40-MHz channels. While 802.11n operates effectively in the 2.4GHz frequency, optimal performance results are realized in the 5GHz frequency.

The methodology behind the CRN performance tests is questionable. The Cisco access point was tested without a WLAN controller – differing from its intended configuration. No attention was paid to using the latest software drivers or product software. CRN provides no transparency to product sourcing and configuration methodology and refused to offer Cisco the opportunity to troubleshoot for fear of revealing the source of the product and its configurations.

For an unbiased and transparent review of Cisco’s product performance, readers should shift their attention to the Network Computing performance review. The performance review is summarized in the article, “First Look: Cisco's 1250 802.11n AP” and can be read here: http://www.networkcomputing.com/channels/wireless/showArticle.jhtml?articleID=206901320. This review shows the performance of the Aironet 1250 as reaching 154.9 Mbps. The 300 Mbps as referenced by CRN is the link speed. It is well understood that the TCP/UDP throughput reported in performance tests is approximately half that of the link speed (due to overhead associated with the 802.11 standard). Cisco has achieved phenomenal success with the Aironet 1250 with over 30,000 units shipped - the fastest selling access point in Cisco history. Leading customers like Duke University have shown real-world performance results just shy of 130 Mbps.

CRN fell short on delivering a complete and transparent test due to flawed testing methodology. Only by testing products with the latest drivers and software code can CRN expect to receive results commensurate with the true performance of the product.

Posted by Chris Kozup at 12:28 PM Permalink | Comments (2) | TrackBacks (0)