Meru Networks has introduced what it says is the first wireless LAN solution optimised for delivering high-quality video over the new generation of IEEE 802.11n networks.
The company’s Video Services Module (ViSM) is designed to address video-delivery issues specific to 802.11n networks – which are susceptible to unpredictable loss rates that can negatively impact video quality.
The module applies application-aware optimisation techniques to web streaming and real-time multicast video, underlying technologies that enable a broad array of video applications, from wireless projection, IPTV and event simulcast to videoconferencing, telepresence and video surveillance.
Vaduvur Bharghavan, Meru’s chief technology officer, said video-based applications are becoming pervasive in schools, health-care institutions and other enterprises because they boost productivity significantly for a relatively low cost.
But he said high-definition video delivery over wireless is especially challenging because it combines the high bandwidth requirements of heavy data traffic with the delay sensitivity and loss characteristics of voice traffic.
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| Vaduvur Bharghavan, Meru’s chief technology officer |
"And while 802.11n dramatically increases available bandwidth, it also increases per-transmission error rates," he said.
"For multicast applications this translates to lost portions of video; for web video streaming it can mean stalled video or the loss of voice-video synchronization."
Bharghavan said the power of the ViSM lies in its unique virtualized WLAN architecture, which gives every client device its own dedicated wireless ‘port’.
"With Meru’s Virtual Port, each client gets its own copy of the multicast application traffic, delivered at the highest possible data rate and unaffected by the transmission or power-save behaviour of other clients," he said.
"In other vendors’ legacy micro-cell solutions, which force all clients to share the same wireless resource, some clients will always suffer in terms of the timely delivery of multicast frames when other clients require buffering of traffic, thus causing multicast video delays for every client."
The ViSModule works by using several mechanisms to deliver video traffic based on application and user characteristics.
The company says this allows scaling to large numbers of concurrent video sessions without appreciably degrading user experience.
- Application-aware prioritization: synchronises the voice and video components of a video stream, adapting the delivery of each frame based on its importance to the application. Higher-priority MPEG-4 AVC/H.264 marked frames are transmitted with greater assurance of reliability and timeliness.
- User- and role-based policy enforcement: provides granular control over application behaviour (e.g., a teacher can be assigned higher priority than a student).
- Seamless video-optimised handoff: proactively reroutes the multicast delivery tree to prevent lost video frames during a transition between access points, and ensures zero-loss for mobile video.
- Multicast group management: optimises delivery to only those virtual ports whose clients are members of the multicast group, reducing network waste both wirelessly and on the wired network.
- Graphical visualisation: reveals which clients are running which applications (data, voice, video) to aid in monitoring network-wide application performance.
ViSM is available in June as an add-on module to Meru’s System Director software. For a network with 100 wireless access points, the module is priced at USD $7,995.
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