target = "https://www.rfc-editor.org/rfc/rfc9000#section-13.4.2.2"

# 13.4.2.2.  ECN Validation Outcomes
#
# If validation fails, then the endpoint MUST disable ECN.  It stops
# setting the ECT codepoint in IP packets that it sends, assuming that
# either the network path or the peer does not support ECN.
# 
# Even if validation fails, an endpoint MAY revalidate ECN for the same
# path at any later time in the connection.  An endpoint could continue
# to periodically attempt validation.
# 
# Upon successful validation, an endpoint MAY continue to set an ECT
# codepoint in subsequent packets it sends, with the expectation that
# the path is ECN capable.  Network routing and path elements can
# change mid-connection; an endpoint MUST disable ECN if validation
# later fails.

[[spec]]
level = "MUST"
quote = '''
If validation fails, then the endpoint MUST disable ECN.
'''

[[spec]]
level = "MAY"
quote = '''
Even if validation fails, an endpoint MAY revalidate ECN for the same
path at any later time in the connection.
'''

[[spec]]
level = "MAY"
quote = '''
Upon successful validation, an endpoint MAY continue to set an ECT
codepoint in subsequent packets it sends, with the expectation that
the path is ECN capable.
'''

[[spec]]
level = "MUST"
quote = '''
Network routing and path elements can
change mid-connection; an endpoint MUST disable ECN if validation
later fails.
'''