[Sis-csi] Handovers (was: RE: CCSDS Cislunar Telecon)

[Adrian J. Hooke]

At 07:37 AM 9/7/2006, Kearney, Mike wrote:
>On the topic of all traffic passing the MOC (MCC or whatever)...  After 
>the ISS experience, there is a stronger desire in the manned operations 
>community to allow multiple facilities to connect through the ground 
>station to the spacecraft.  There were major constraints on operations 
>capabilities (especially during Hurricane Rita) that would have been 
>alleviated if WSGT could have been reconfigured easily to connect to a 
>US-based backup MCC.

Mike: if there had been a program requirement in place to be able to 
rapidly switch to a backup control center, then wouldn't this handover 
capability have been implemented and tested in the ISS operational systems? 
Presumably, there wasn't such a requirement and so neither WSGT nor MCC 
Houston were designed to support it. The lack of the capability probably 
had nothing to do with protocols - as you note, the AOS architecture that 
has been in place since 1990 was designed to easily support such a transfer 
- and everything to do with programmatics and implementation choices.

>I know that there are traditional ways to do that (AOS VCs) without 
>placing a router/IP gateway at the ground station.  But there is a 
>perception in some corridors that going IP based from the ground station 
>out gives a needed capability to deal with contingencies, and allows 
>low-cost reconfigurations when ops concepts change.

Isn't whether or not such a handover is done by connecting at the Link or 
Network layer an absolutely trivial and insignificant level of detail and 
complexity compared with the staggering amount of vehicle operational state 
that has to be handed-off between the primary and backup control centers?

This topic seems like a red herring. Protocol geeks should be very wary 
about fostering "perceptions" that this or that protocol can solve the 
world's problems. There are much larger issues at play here, and they all 
have to do with implementation, operational culture, cost and risk.

///adrian

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