On Aug 20, 2009, at 12:22 PM, Shahram Davari wrote:
Hi,
I have a question regarding Authentication. The BFD reception rules say:
"If the A bit is set and no authentication is in use (bfd.AuthType is zero), the packet MUST be discarded."
"If the A bit is clear and authentication is in use (bfd.AuthType is nonzero), the packet MUST be discarded."
How do we know the value of bfd.AuthType? Is it a configured value or is it derived from the "Auth Type" field of the received BFD packets? if it is derived from received BFD packets the value zero is reserved for "Auth Type" and is not defined.
It's a known value outside of the spec; configuration is one way to do it.
Any explanations?
Also I noticed that the text says SHA1 is mandatory and others are optional. Which SHA1 does it mean? the Keyed or Meticulous Keyed SHA1? Can we change then Mandatory to Simple Password?
SHA1 is mandatory to implement (for interoperability) but not to deploy. The spec is ambiguous as to regular vs. meticulous; I'll fix it to say that both must be supported (99.9% of the work is in the hash algorithm itself; the difference between regular and meticulous is a few lines of code.)
--Dave
