[Sis-csi] Communications Endpoints

[Keith Scott]

This was just to make the standard MobileIP point: IP assumes a binding
between IP address and location in the network topology that mobility
breaks.  Spacecraft that attach to the Internet via different ground
stations will act like mobile nodes in this context (with some caveats).

In the 'no boundaries' IP scenario, no, the comm center wouldn't necessarily
know who's communicating or when.  The comm center, or even the S/C
manufacturer, could house a MobileIP home agent (maybe for the entire S/C
via network mobility), and each groundstation could be a foreign agent.
Most data might not even flow through a control center in this case (some
setup info would if the HA is at the control center).

There are a number of other approaches, including advertising all the SC
addresses from the control center and dynamically stitching up tunnels to
ground stations from there.  This is slightly different than regular
MobileIP, in that all data would flow through the control center (there
would be no provision for eliminating the 'triangle routing problem').  It
has advantages, however, security being one of them.

		--keith

> -----Original Message-----
> From: Ed Greenberg [mailto:egreenbe at jpl.nasa.gov] 
> Sent: Thursday, March 10, 2005 1:28 PM
> To: Keith Scott
> Subject: Re: [Sis-csi] Communications Endpoints
> 
> At 07:46 AM 3/10/2005 -0500, you wrote:
> >Mobility: Space assets may attach to the terrestrial Internet though 
> >some number of ground stations.  Terrestrial endpoints that want to 
> >route data to space must send packets towards the correct ground 
> >station.  While normal IP routing could in principle take 
> care of this 
> >(provided the correct ground station started advertising the 
> space IP 
> >addresses in routing protocol updates at the right times), 
> in practice 
> >the time required for IP routing tables to converge is too 
> long to make 
> >this a viable alternative if short-to-moderate length passes 
> are to be supported.
> 
> 
> Do mean to say that the operations center will not know which 
> node will be 
> in contact with the S/C ?   I would suspect that the Ops 
> center to comm 
> node will use a secure socket set up between the two points.
> 
> 
> Progress is impossible when you always do things the way they 
> have always been done. 
> 
>