[Chris Harlan] "The one thing I know you are mistaken about in the above paragraph is "PCIe is just one protocol that can be multiplexed over it." PCIe and DisplayPort are the ONLY two bus level protocols muxed by Thunderbolt at that abstraction layer."
Um, yes, I know. How does this make me "mistaken"? PCIe
is only one of the protocols that can be multiplexed over Thunderbolt. There's one other protocol that has that status now, and hypothetically there could be more in the future (though PCIe is pretty general purpose, and multiplexing more protocols would require more complex cross-connects in the host system, so it might not be worth the trouble).
In any event, PCIe's ability to handle star/tree topologies wouldn't matter even if it
were the only protocol that could be multiplexed over Thunderbolt -- the abstraction provided by Thunderbolt would still allow for topologies PCIe didn't support. (And, again, PCIe actually
does support star topologies, so even if Thunderbolt literally
were just external PCIe hubs would be possible.)
[Chris Harlan] " I've found many references to hubs or potential hubs for upper level protocols, but NONE for anything at that level."
Because you're ignoring a clear reference saying Thunderbolt supports tree/star topologies. Again, look at the PDF I linked to. This is clearly labeled as a transport layer feature. It's true that nobody has announced a product yet, but hub products weren't very common for FireWire either -- most people's needs are met by daisy chaining (with technologies that support it), so hubs tend to be rare.
[Chris Harlan] "Notice the focus on the daisy chain as the mode of connection."
Doesn't mean very much. FireWire
absolutely supports hubs (there were a few on the market), but they were rarely used, and a brief overview of how the technology worked might well ignore the possibility.
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