target = "https://www.rfc-editor.org/rfc/rfc8899#section-1.3"

# 1.3.  Path MTU Discovery for Datagram Services
#
# Section 5 of this document presents a set of algorithms for datagram
# protocols to discover the largest size of unfragmented datagram that
# can be sent over a network path.  The method relies upon features of
# the PL described in Section 3 and applies to transport protocols
# operating over IPv4 and IPv6.  It does not require cooperation from
# the lower layers, although it can utilize PTB messages when these
# received messages are made available to the PL.
# 
# The message size guidelines in Section 3.2 of the UDP Usage
# Guidelines [BCP145] state that "an application SHOULD either use the
# Path MTU information provided by the IP layer or implement Path MTU
# Discovery (PMTUD)" but do not provide a mechanism for discovering the
# largest size of unfragmented datagram that can be used on a network
# path.  The present document updates RFC 8085 to specify this method
# in place of PLPMTUD [RFC4821] and provides a mechanism for sharing
# the discovered largest size as the MPS (see Section 4.4).
# 
# Section 10.2 of [RFC4821] recommended a PLPMTUD probing method for
# the Stream Control Transport Protocol (SCTP).  SCTP utilizes probe
# packets consisting of a minimal-sized HEARTBEAT chunk bundled with a
# PAD chunk as defined in [RFC4820].  However, RFC 4821 did not provide
# a complete specification.  The present document replaces that
# description by providing a complete specification.
# 
# The Datagram Congestion Control Protocol (DCCP) [RFC4340] requires
# implementations to support Classical PMTUD and states that a DCCP
# sender "MUST maintain the MPS allowed for each active DCCP session".
# It also defines the current congestion control MPS (CCMPS) supported
# by a network path.  This recommends use of PMTUD and suggests use of
# control packets (DCCP-Sync) as path probe packets because they do not
# risk application data loss.  The method defined in this specification
# can be used with DCCP.
# 
# Section 4 and Section 5 define the protocol mechanisms and
# specification for Datagram Packetization Layer Path MTU Discovery
# (DPLPMTUD).
# 
# Section 6 specifies the method for datagram transports and provides
# information to enable the implementation of PLPMTUD with other
# datagram transports and applications that use datagram transports.
# 
# Section 6 also provides recommendations for SCTP endpoints, updating
# [RFC4960], [RFC6951], and [RFC8261] to use the method specified in
# this document instead of the method in [RFC4821].

[[spec]]
level = "SHOULD"
quote = '''
The message size guidelines in Section 3.2 of the UDP Usage
Guidelines [BCP145] state that "an application SHOULD either use the
Path MTU information provided by the IP layer or implement Path MTU
Discovery (PMTUD)" but do not provide a mechanism for discovering the
largest size of unfragmented datagram that can be used on a network
path.
'''

[[spec]]
level = "MUST"
quote = '''
The Datagram Congestion Control Protocol (DCCP) [RFC4340] requires
implementations to support Classical PMTUD and states that a DCCP
sender "MUST maintain the MPS allowed for each active DCCP session".
'''