Re: [dispatch] SIP and GSM/UMTS with OpenBTS

[Jim Forster <[e-mail]>]

>>> Interesting.  But, the 4G/LTE network is an IP internet of sorts.
>>> The SIP/IMS components do not need to be in the radio network,
>>> and thus not at the locations where the power is constrained.
>> One of the nice properties of an openBTS install in a remote location is that it
>> can still function as a local 'pbx' at times when the internet link is down. This turns out to
>> be fabulously useful in a crisis. If you delegate all the logic out to a cloud service that stops being true.
>> 
>> Tim.
> I agree violently, the challenge here is to design the distributed protocol(s) add-ons that would enable
> building a sip/GSM network out of hundreds or more autonomous BTS's.
> 
> Gullik

I agree mostly with both of you:

 * Standalone/disconnected OpenBTS's have good value in emergency response or remote work environments.  Turn it on phones in the footprint can call each other; no backhaul or Core Network.  In some cases that are connected, over a thin link, there is a great bandwidth savings, and reliability improvement, by having a local switch.  I believe the Antarctic research station paid for its OpenBTS in a few months of operation, due to savings in satellite bandwidth over the GSM standard approach with the BSC/MSC on the other side of the satellite link. Plus, solar storms would knock out the link and and disable even local calls.

 * There are indeed challenges (and value) in large networks

I still owe the list a diagram which would facilitate understanding and discussion.

  -- JIm