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scionassociation / scion-dp_I-D

Specification of the SCION data plane
https://scionassociation.github.io/scion-dp_I-D/
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SCMP - Be careful about forward references #8

Closed elear closed 3 months ago

elear commented 4 months ago

SCION also includes its own protocol to communicate failures to endpoints, the SCION Control Message Protocol (SCMP). This protocol will be described in a separate document, which will follow later.

Text like this doesn't stand on its own.

nicorusti commented 3 months ago

The SCMP specification is likely not be necessary for a self-contained data plane.

In this draft, there are a few mentions of SCMP that are not necessary for the DP spec: the text below is just an example and could be deleted: 

   A similar mechanism is possible for on-path routers, for example to
   send SCION Control Message Protocol (SCMP) messages to the sender of
   the original packet.
  The remaining protocols, which do not carry the
      length information directly (e.g., the SCION Control Message
      Protocol SCMP)

There are 4 mentions of using the SCMP parameter problem when MAC verification fails. This can be useful for debugging. Ig MAC verification fails because of an attack, it does not make sense to send an error message back. This is an optional signal that routers can send, so this could be omitted.

We could then only leave the protocol number in table 10.

elear commented 3 months ago

If SCMP is not important to the work, you can still mention it informationally, but then you must properly reference it.

nicorusti commented 3 months ago

Hi @elear , we removed forward references to SCMP, see change diff. We now mention SCMP at the end of the draft, and we use our developer documentation as a reference: https://docs.scion.org/en/latest/protocols/scmp.html

Does that work?

An alternative reference would be the SCION book [CHUAT22] section 4.7.