All things related to multicast

[Bill Nickless <>]

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At 07:54 PM 7/7/2003 +0100, Lloyd Wood wrote:
>(multicast makes a lot of sense in a satellite broadcast environment,
>  where link utilisation matters. If you can resell your
>  constrained capacity, multicast increases, not decreases, your
>  revenue.)

Exactly right.  I ran into an example of that recently.

Check out Nanometrics Seismological Instruments.  They market satellite 
networks of seismometers.

    http://www.nanometrics.ca/products/naqs.htm

Nanometrics uses UDP/IP over multicast for transport of data across the 
satellite channel.  It's a slick setup.  From that web page:

    NAQS Server has all the hooks to support large network
    configurations in mission critical installations. NAQS
    Server supports UDP/IP multicast. This permits fully independent
    installations to operate concurrently, simultaneously processing
    data from the same remote stations.

    With two or more NAQS Server systems operating in parallel,
    customers can migrate system configuration changes and software
    updates from a secondary test installation to the primary NAQS
    Server system. This approach to system administration effectively
    eliminates system down time due to incorrect configuration.

Nanometrics' big selling point is how efficiently they use the space 
segment bandwidth for a seismological sensor network.  Their example:

    Nanometrics recommends allocation 6.6kbps for a typical 3 channel
    100sps seismograph station. This provides the bandwidth required
    for continuous first-difference compressed data, error-correction
    retransmission and protocol overheads. A single carrier of 112 kbps
    can support 17 such channels: 16 remotes and 1 central hub. Libra
    can efficiently support networks of any number of remotes by
    configuring data rates and adding carriers as needed.

    Intelsat, which operates satellites around the world, publishes
    $5800 per year as their standard tariff rate for a five year, 100
    kHz Ku-Band spot beam lease.  If a network consists of 16 remotes,
    the monthly operating cost of each is $30.

(Disclosure statement: I'm not connected with Nanometrics in any way, 
either as an investor, customer, or vendor.  I sat through one of their 
presentations a few weeks ago and was positively impressed.)

===
Bill Nickless    http://www.mcs.anl.gov/people/nickless      +1 630 252 7390
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