[Sis-csi] RE: networking details

[Scott Burleigh]

Assi Friedman wrote:
>
> I would like to point out that a lot of discussion needs to go into 
> the physical/link layers of this migration. CCSDS as-is is has its 
> history significantly influenced from the STDN era. This history does 
> not make it very conducive to IP in space.
>
Hi, Assi.  Can you go into a little more detail on why the CCSDS 
link-layer protocols are not very conducive to IP in space?

Since they were designed for use in -- and are heavily (and very 
successfully) used in -- space, and are the international standard link 
protocols for communication with spacecraft, I'm guessing it's not the 
"in space" part of the problem that you think the protocols are not 
suitable for.  So I'm concluding that you think that they are not a 
suitable medium for carrying IP packets, right?  Is there something 
about IP packets that makes them okay to carry in Ethernet frames, PPP, 
SONET, etc. but not okay to carry in, say AOS frames?
>
> Migrating to IP will require us to address the physical/link layers.
>
"Require" is kind of a strong word to use here.  Are you saying that 
it's impossible to convey IP traffic over the CCSDS link protocols?  Or 
are you saying that it's just operationally more expensive to convey IP 
traffic to and from spacecraft over CCSDS link protocols than over some 
other link protocols?  In either case, can you point to some published 
studies that demonstrate the deficiencies of the CCSDS links?

Scott
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