First, handling of optional attributes depends on whether you knows them,
not on whether a peer knows them.
Unknown optional transitive attributes are re-propagated, but with set
'partial' flag. For details, see bgp_export_attr() function.
Thanks for the answer I really appreciate it.
Yeah form the RFC I get that unknown optional transitive attributes are
re-propagated.
I was more interest in acceptance part, the RFC 4271, section 5, 5th
paragraph says:
"... Paths with unrecognized transitive optional attributes SHOULD be
accepted. ..."
This SHOULD was confusing me.
This take me to an other question,
Given that I already know the destination d (that i learnt with an
unknown optional transit attribute that I re-propagated with the
'partial' flag).
At some point I receive an UPDATE for the destination d, and the only
attribute that is different is the unknown optional transit one.
At this point a bird node, in first place can recognize that only the
unknown optional transit attribute has been changed? and in addiction,
if it recognize it, the UPDATE will be re-propagated with the optional
transit attribute and the flag 'partial', am I right?
Thanks for the help,
Mattia
