target = "https://www.rfc-editor.org/rfc/rfc9002#section-7.3.2"

# 7.3.2.  Recovery
#
# A NewReno sender enters a recovery period when it detects the loss of
# a packet or when the ECN-CE count reported by its peer increases.  A
# sender that is already in a recovery period stays in it and does not
# reenter it.
# 
# On entering a recovery period, a sender MUST set the slow start
# threshold to half the value of the congestion window when loss is
# detected.  The congestion window MUST be set to the reduced value of
# the slow start threshold before exiting the recovery period.
# 
# Implementations MAY reduce the congestion window immediately upon
# entering a recovery period or use other mechanisms, such as
# Proportional Rate Reduction [PRR], to reduce the congestion window
# more gradually.  If the congestion window is reduced immediately, a
# single packet can be sent prior to reduction.  This speeds up loss
# recovery if the data in the lost packet is retransmitted and is
# similar to TCP as described in Section 5 of [RFC6675].
# 
# The recovery period aims to limit congestion window reduction to once
# per round trip.  Therefore, during a recovery period, the congestion
# window does not change in response to new losses or increases in the
# ECN-CE count.
# 
# A recovery period ends and the sender enters congestion avoidance
# when a packet sent during the recovery period is acknowledged.  This
# is slightly different from TCP's definition of recovery, which ends
# when the lost segment that started recovery is acknowledged
# [RFC5681].

[[spec]]
level = "MUST"
quote = '''
On entering a recovery period, a sender MUST set the slow start
threshold to half the value of the congestion window when loss is
detected.
'''

[[spec]]
level = "MUST"
quote = '''
The congestion window MUST be set to the reduced value of
the slow start threshold before exiting the recovery period.
'''

[[spec]]
level = "MAY"
quote = '''
Implementations MAY reduce the congestion window immediately upon
entering a recovery period or use other mechanisms, such as
Proportional Rate Reduction [PRR], to reduce the congestion window
more gradually.
'''