On Sep 1, 2009, at 3:40 PM, Margaret Wasserman wrote:
Actually, the specification says that the reserved bit are set to zero on transmit and ignored on receipt. So, they can be used for extensions that are non-harmful to existing nodes without any need to explicitly document those reasons on the specification unless/ until we are ready to document what they are actually being used for.
On re-reading, I realized that this is at least semi-incomprehensible...The second sentence should have read: So, the reserved flags can be used for extensions that are non-harmful to existing nodes. When we want to try out a new extensions that isn't ready to be formally considered by the WG, we can do that without the need to reserve a specific flag in the document. We can wait to define a new flag in the document until we know what that flag will be used for, and how nodes that send/receive that flag are supposed to behave.
In the case of the R-bit, I think it would be better to wait (leaving the flag reserved until we are ready to fully document it) than to reserve a flag without any real explanation of how it will be used.
I have the same thought about the M bit in the mapping replies. Margaret
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