REVIEW: HP E-MSM460 Dual Radio 802.11n Access Point

Until recently, the idea of taking WLAN technology and achieving near Gigabit Ethernet wired speeds was not a realistic proposal―and that’s putting it politely. However, with the IEEE 802.11n standard finally bearing fruit we have―in theory at least―the ability to consider a wired network replacement technology where that makes sense; a listed building, where wire is difficult to lay or is vulnerable to damage, for example.

Or, even as the classic addition to a wired network, at least the idea is that users won’t see any performance difference when switching between the two formats. The HP E-MSM460 our review focuses on here is very much looking to offer performance levels approaching realistic Gigabit Ethernet performance, combined with the ability to fully support a legacy wireless client environment without impacting on performance of the new generation of .11n clients. So let’s now take a look at the product and see if it delivers in practise.

Features

HP’s claim is that it is the first vendor in the industry to offer near Gigabit Ethernet WLAN client access. Now that’s a bold claim! So what is the basis of this claim? At the heart of the technology within the E-MSM460 is three-spatial-stream, dual 802.11n radios APs delivering a potential 450Mbps per radio, so 900Mbps in total.

Since its acquisition of Enterprise WLAN specialist Colubris Networks in 2009, HP has been able to significantly expand its wireless offerings, particularly in the enterprise area and the E-MSM460 AP actually targets both the SMB and enterprise business communities. One reason it can do this is because it can work both in autonomous mode (controller free) and via an HP WLAN controller such as the E-MSM710 or E-MSM760.

In this way, from a budgetary perspective, for smaller businesses as a standalone device with enterprise functionality and performance it makes a lot of sense, if that combination of performance and security for a small number of users is required. Equally, if multiple APs, even in their 10s or 100s, are being deployed, the MSM460 is equally suited to working with a controller device, available separately to support multiple APs from a single device.

HP talks a lot about its use of beam forming technology to improve RF coverage areas and reduces roaming “dead” spots. So what is it exactly? Beam forming is a type of RF (radio frequency) management in which an access point uses multiple antennas to send out the same signal. By sending out multiple signals and analysing the feedback from clients, the WLAN infrastructure can adjust the signals it sends out and determine the best path the signal should take in order to reach a client device, shaping the RF beam as it traverses the physical space.

Band steering is another key technology here, used to ensure the highest performing connection for 5GHz capable clients is always chosen where possible. Where an AP contains dual radios, as does the E-MSM460, typically one radio is set to the 5GHz frequency (for 802.11a/n clients) and the other is set to 2.4GHz (for802.11b/g clients).

By default, most clients are configured to prefer the 2.4GHz band, but with band steering 5GHz compatible clients are automatically “steered” to the correct radio, so always connect at the higher frequency. This is typically both less congested and is higher performing than the 2.4GHz space. It also improves performance for clients which remain on the 2.4GHz network, by reducing the numbers of users on that frequency. Concurrent radio operation in 5GHz band is also supported on HPs MSM466 AP (not reviewed in this report).

Another interesting feature, designed to optimise traffic is what HP calls a VSC or Virtual Service Community. This is a collection of configuration settings that define key operating characteristics of the service controller and controlled APs and works in conjunction with the SSID and other identifiers.

Management wise, in standalone (autonomous) mode, management is via a GUI. Simply point a browser at the MSM460 IP address and access to the GUI becomes available. In controller-based environments, umbrella management options are available, enabling complete control of the wired and wireless infrastructure from the one management interface.

For the testing we had two setups: one with the E-MSM460 in autonomous mode and secondly using an MSM765zl controller with a mix of APs including E-MSM460s. In both cases we had a mix of clients including .11b/g and .11n (2.4GHz and 5GHz). At the E-MSM460 we configured a single VLAN and single VSC.

For the band steering we set up the two radios at different frequencies, one at 2.4GHz support all .11b/g/n traffic and one at 5GHz supporting .11n traffic only. Using a 5GHz capable .11n client (supporting both frequencies) we put band steering to the test and found that the client connected to the 5GHz radio every time. Unsurprisingly, we had no problems connecting a mix of 2.4GHz clients concurrently during the testing.

For the performance tests we used the Iperf public domain test tool and a selection of HP laptops and server, in conjunction with an MSM765zl controller, to which the APs were directly connected. Connecting a .11n client at the 5GHz frequency, we saw a connection speed of 450Mbps, as expected.

We created a multi-threaded Iperf test configuration (settings were: Iperf204 – -c IP address –w 16M –p 10000 –P20 (threads)) with a Diffserv-based QoS configuration on the E-MSM460 and (for the record) band steering disabled in a pure .11n environment and WPA2 encryption on the laptop clients, in order to ensure a realistic test setup. We found that best and most reliable performance was with both radios enabled―a good sign―and that, while we did see some fluctuation in performance levels, we saw a sustained peak of 446Mbps―as close to the 450Mbps limit as is realistically possible.

Summary

Overall, we found the E-MSM460 to be both high performing and flexible enough to suit a wide variety of working environments and companies. Yes, at £714, it is significantly more expensive than a “High Street” brand intended for casual home use but there is a reason for that―this AP is truly fit for business purpose and is a great way to either extend a wired network without users noticing any significant drop-off in performance when moving between wired and wireless, or―in the right scenario―as a full wired replacement technology.

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