Draft: draft-ietf-taps-impl

Commentary: Just check " connected " - in case we mean connection - oriented ; and that usage of " connect " is sane , we need care . 
 UDP is best described as connectionless , not unconnected : it has no notion of a connection , where " unconnected " might imply a particular usage pattern for a protocol that also supports connections . 
 YES ! UDP is " connectionless " ; confusing APIs do support a " connected mode " . Please remove unconnected .
Paragraph (version A):
Implementations may select the criteria by which a leaf node is
considered to be successfully connected differently on a per-protocol
basis.  If the only protocol being used is a transport protocol with
a clear handshake, like TCP, then the obvious choice is to declare
that node "connected" when the last packet of the three-way handshake
has been received.  If the only protocol being used is an
"unconnected" protocol, like UDP, the implementation may consider the
node fully "connected" the moment it determines a route is present,
before sending any packets on the network, see further unconnected-
racing.
Paragraph (version B):
Implementations may select the criteria by which a leaf node is
considered to be successfully connected differently on a per-protocol
basis.  If the only protocol being used is a transport protocol with
a clear handshake, like TCP, then the obvious choice is to declare
that node "connected" when the last packet of the three-way handshake
has been received.  If the only protocol being used is an
connectionless protocol, like UDP, the implementation may consider
the node fully "connected" the moment it determines a route is
present, before sending any packets on the network, see further
connectionless-racing.
Paragraph (version A):
While protocols that use an explicit handshake to validate a
Connection to a peer can be used for racing multiple establishment
attempts in parallel, "unconnected" protocols such as raw UDP do not
offer a way to validate the presence of a peer or the usability of a
Connection without application feedback.  An implementation should
consider such a protocol stack to be established as soon as the
Transport Services system has selected a path on which to send data.
Paragraph (version A):
However, if a peer is not reachable over the network using the
unconnected protocol, or data cannot be exchanged for any other
reason, the application may want to attempt using another candidate
Protocol Stack.  The implementation should maintain the list of other
candidate Protocol Stacks that were eligible to use.
Paragraph (version B):
While protocols that use an explicit handshake to validate a
Connection to a peer can be used for racing multiple establishment
attempts in parallel, connectionless protocols such as raw UDP do not
offer a way to validate the presence of a peer or the usability of a
Connection without application feedback.  An implementation should
consider such a protocol stack to be established as soon as the
Transport Services system has selected a path on which to send data.
Paragraph (version B):
However, if a peer is not reachable over the network using the
connectionless protocol, or data cannot be exchanged for any other
reason, the application may want to attempt using another candidate
Protocol Stack.  The implementation should maintain the list of other
candidate Protocol Stacks that were eligible to use.
Paragraph (version A):
Unconnected protocols such as UDP and UDP-lite generally do not
provide the same mechanisms that connected protocols do to offer
Connection objects.  Implementations should wait for incoming packets
for unconnected protocols on a listening port and should perform
four-tuple matching of packets to either existing Connection objects
or the creation of new Connection objects.  On platforms with
facilities to create a "virtual connection" for unconnected protocols
implementations should use these mechanisms to minimise the handling
of datagrams intended for already created Connection objects.
Paragraph (version B):
Connectionless protocols such as UDP and UDP-lite generally do not
provide the same mechanisms that connected protocols do to offer
Connection objects.  Implementations should wait for incoming packets
for connectionless protocols on a listening port and should perform
four-tuple matching of packets to either existing Connection objects
or the creation of new Connection objects.  On platforms with
facilities to create a "virtual connection" for connectionless
protocols implementations should use these mechanisms to minimise the
handling of datagrams intended for already created Connection
objects.
Paragraph (version A):
Unconnected.  Unconnected protocols do not establish explicit
state between endpoints, and do not perform a handshake during
Connection establishment.
Paragraph (version B):
Connectionless.  Connectionless protocols do not establish
explicit state between endpoints, and do not perform a handshake
during Connection establishment.