Mesh Without Wires

November 28, 2009

Mesh and Mobility – Marriage Made in Wireless Heaven?

Filed under: Technology — kseniacoffman @ 8:27 pm
Tags: ,

Earlier in November Firetide announced Seoul Subway video surveillance system delivering real-time streaming to and from trains moving at 50 mph [pictures]. This project is kind of a big deal. Apart from the facts that:

  • this is the first such deployment underground;
  • the system delivers 20 Mbps of capacity for high-quality, 30-frames-per-second video;
  • initial phase of the project is 1,000 nodes
  • it’s deployed in extremely harsh conditions with reflective metal, vibration and dust;

the key to the deployment is Firetide’s mesh infrastructure mobility: the ability to maintain real-time connections between fixed and mobile mesh nodes moving at high speeds –  without dropping packets and introducing latency or jitter

“Mobility” is a frequent requirement we hear about from our customers, and by mobility we mean hard-core infrastructure mobility, not “client mobility” as Wi-Fi access point vendors define it: between APs and smart phones, laptops, etc. Wi-Fi access architecture is enough to support non-critical low-bandwidth data, but for challenging environments and to support real-time video streaming or VoIP, only mesh will fit the bill.

Similarly, you cannot truly implement mobility with point-to-multipoint equipment, because of the central ‘command-and-control’ architecture, which does not allow for roaming. Mesh, with its distributed architecture and intelligence can support mobility within the mesh, and even roaming across multiple meshes.

Mobile real-time video is the wave of the future – for city-wide public safety, industrial sites, campus environments, mining and transportation. (Tip: you will need Firetide Mobility Controller, if your network design involves roaming between meshes).

For different approaches to ‘mobile video,’ see my post Defining Mobile Video – Notes From IWCE Wireless Killer Apps Panel.


  1. How hard is it to implement mobility?

    A friend implemented mobility with Cisco equipment for an IP video system. His feedback was that integration was incredibly complex and time consuming (he’s a Cisco CCNP). It was a classic ‘project from hell’.

    I would expect mobile applications to be more complex than fixed. What I am curious to know is how much more complex?

    Comment by John Honovich — November 30, 2009 @ 12:12 pm | Reply

    • Hi John, yes mobility installations are more complex from the design/installation standpoint. In Firetide mesh, one radio is used for data and the other for roaming + you have to deploy a Mobility Controller SW to manage the roaming connections. So there are more variables you are dealing with.

      However, achieving mobile video with Cisco gear is way more challenging since their architecture is Mesh APs (mesh access points) based using WDS vs our “infrastructure mesh” (dedicated dual-radio backhaul) & proprietary flow-based routing protocol, which enables seamless hand-off between nodes and roaming between meshes. So thanks for pointing out Cisco’s challenge with mobility :-)

      With Seoul, the process was rather straightforward — mesh really shines in an infrastructure mobility scenarios like this. I’m sure it was challenging because of the conditions in the tunnels (vibrations, reflections from metal parts), but it was not a “deployment from hell.”

      Comment by kseniacoffman — November 30, 2009 @ 3:25 pm | Reply

  2. Regarding installation complex comparison between WiFi & Ethernet in such a harsh environment, I would expect WiFi to be way less complex – Imagine how hard running wires more than 100 plus miles underneath the ground during 12 AM ~ 4 AM (this is only allowed installation window)…

    Anyway, here are few questions though, (1) how long did it take or will take to complete the installation. (2) When is it scheduled for full service? (3) What kind applications will be carried? Only video surveillance inside train or something else?

    BTW: I guess this is for SMRT (there are two subway/metro systems in Seoul, SMRT & SeoulMetro)…


    Comment by gowirefree — March 20, 2010 @ 4:37 pm | Reply

    • Re: wireless vs wire – the subway tunnels already had fiber installed, so the wireless enables video transmission between fixed and mobile infrastructure. The fixed mesh nodes (in the tunnels) are connected via fiber, and they ‘mesh’ with the nodes on the moving trains as they pass by. The purpose of mesh is to transmit video off/onto the trains, and also to manage hand-offs from one fixed mesh node to another, as well as manage roaming between meshes (this is a multi-mesh setup).

      The project is currently in deployment. Unfortunately, I’m not able share details on the schedules, since it would require permission from the integrator and SMRT. (Yes, this project is for SMRT – Seoul Metropolitan Rapid Transit Corporation.)

      As far as applications go, the primary driver is security video: both from the station to the train operator, and from inside of passenger trains to a monitoring center. Plus they plan video streaming of public announcements and commercial advertisements onto passenger train monitors. Other applications may be forthcoming.

      Comment by kseniacoffman — March 22, 2010 @ 10:04 am | Reply

  3. This is a great example of a perfect application for wireless. We are seeing more and more demand for public transportation wanting to provide Broadband to its riders and for the use of video for the transportation authorities. In this model the use of linear mesh makes a lot of sense. The ability to do quick hand offs is essential in a roaming environment. The other issue in a tunnel environment is the amount of multipath that occurs. Proper radio and antenna choice is crucial here.

    Wireless can do quick hand offs but the most difficulty is proper setup of the switching that is needed to route the packets efficiently. When you start passing video at quick hand offs intervals the need for QOS has to be implemented correctly.

    This is a great case study!
    Good Job!

    Comment by Joe Wargo — August 25, 2010 @ 12:16 pm | Reply

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