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scionassociation / scion-cp_I-D

Specification of the SCION control plane.
https://scionassociation.github.io/scion-cp_I-D/
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Clarify PCB selection policies and how they meet endpoint's needs #16

Closed nicorusti closed 2 months ago

nicorusti commented 3 months ago

From: Joel Halpern There seems to be a philosophical contradiction in section 2.3.1 (Selection of PCBs to propagate) of the control plane document. Given the philosophy of SCION, the goal should be to propagate PCBs with the highest probability of collectively meeting the needs of the end hosts that will perform path construction. Of course, this AS doesn't know that. But the text ignores this distinction.

Tis also relates to rfc9217 section-2.8: how can the incentives of network operators and end users be aligned to realize the vision of path-aware networking, ...

nicorusti commented 3 months ago

Ideally, we'd like not to mandate or recommend any specific selection policy. PCB selection, overall gives some control to the AS, that can "limit" what its endpoint gets. For an AS where endpoints are direct customers, selection policies can be driven by what was bought by customer (e.g. premium paths or not). For a transit AS, this gets more complicated.

nicorusti commented 3 months ago

Maybe giving what we have in the OS as an example could help? https://docs.scion.org/en/latest/dev/design/BeaconService.html#beacon-selection