ICS 5: IBC packet semantics & handling about ibc HOT 6 CLOSED

To-do in spec:

• Reference primitives defined in ICS 3 / ICS 4
• Formalize packet handling algorithm
• Enumerate security properties (particularly replay prevention)
• Define packet data structure
• Define options for receipts, timeouts, alterations to handlers

from ibc.

Datagram formats that need to be defined in this spec (that I can think of so far):

• PACKETFORWARD - forward packet
• PACKETREVERSE - reverse packet (receipt)
• PACKETTIMEOUT - timeout packet (if it needs to be a packet at all)

from ibc.

My thought was directly inspecting the incoming sequence on the other chain to detect timeout, so in that case, PACKETTIMEOUT will not be needed.

from ibc.

I think that depends on which ordering requirements are selected by the channel - sometimes one might want timeouts without ordering - but when possible I agree.

from ibc.

Possibly this may not actually require a separate ICS, I think ICS 4 will determine most of this at the channel level.

from ibc.

Closing, this should just be merged into ICS 4 (#1).

from ibc.