DR
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... CC TPDU Connection confirm TPDU
DR TPDU Disconnect request TPDU
DC TPDU Disconnect confirm TPDU
...
... transport entity shall respond to the CR TPDU with a DR TPDU. The
clearing reason shall indicate why the connection was not accepted.
...
... clearing reason shall indicate why the connection was not accepted.
The source reference field in the DR TPDU is set to zero to indicate
an unassigned reference.
...
... transport entity transmits a
Disconnect Request (DR) TPDU, and the other responds with a Disconnect
Confirm (DC) TPDU. When the DC ...
... entity should consider the transport connection
not to exist (note 1). After the sending of a DR TPDU, other TPDUs
received before the DC TPDU are ignored. It is possible that a
...
... TPDU are ignored. It is possible that a
disconnect collision will occur, when both transport entities send a
DR TPDU at about the same time. This results in each transport entity
...
... transport entity shall
consider the received DR TPDU as a confirmation of its DR TPDU, and
shall not send or expect to receive a DC ...
... entity shall
consider the received DR TPDU as a confirmation of its DR TPDU, and
shall not send or expect to receive a DC TPDU.
...
...
When a connection has been released, after the exchange of DR
and DC, the reference can be re-used immediately (except in Class ...
... 6.9 Spurious Disconnect
Purpose: To deal with the arrival of an "unknown" DR TPDU.
TPDUs and fields used:
...
... Description:
A DR TPDU can be received for a transport connection which
does not exist. Rather than treating this as an error, a DC ...
... does not exist. Rather than treating this as an error, a DC TPDU
should be send back which reflects the references of the DR TPDU.
Note:
...
... - source reference
RJ, DR
- destination reference
...
... entity commencing resynchronization,
and will thus be a RJ, or a retransmitted CR or DR.
The Transport Connection ...
... DR, DT, ED.
NOTE: If DR is sent in response to CR there is no need to
retain a copy of the DR ...
... DR is sent in response to CR there is no need to
retain a copy of the DR.
In the 'confirmation of receipt' variant, applicable only
...
... CR is retained then retransmit it.
o if a DR is retained then retransmit it.
o otherwise, resynchronize data:
...
... and commencement of resynchronization.
o if the first received TPDU os a DR, then transmit
a DC TPDU.
...
... o if the first received TPDU is a RJ, then act as follows:
- if a DR TPDU is retained, then retransmit it
- if a CC ...
... - TPDU in error (string of octets)
DR
- reason code
...
...
The 'Spurious Disconnect' mechanism is used to
deal with receipt of a DR TPDU for an unrecognised Transport
Connection.
...
... by a transport
entity, which, prior to this event has sent a DR, causes this
transport entity to retransmit ...
... entity to retransmit DR. Only DC and DR will be accepted
and interpreted as the completion of the connection release
...
... See Section 6.5 for reference assignment. Receipt of
any TPDU with a reference that is not assigned to a transport
connection other than a Disconnect Request (DR) or Connection
Request (CR) will be ignored.
...
... CR) will be ignored.
Receipt of a Disconnect Request (DR) for an unassigned
Reference will result in a Disconnect Confirm (DC) response.
...
... equal to zero and enter the data phase.
- Reception of a DR will cause termination
of the transport connection as for Classes ...
... transport entity,
which prior to this event has sent a DR, causes this transport
entity to retransmit ...
... entity to retransmit DR. Only DC and DR will be accepted and
interpreted as the completion of the connection clearing sequence.
...
... reference which is in the frozen state. The
response to such a TPDU should be a DR TPDU.
7.4.4.1 Connection Request ...
... transport connection.
The DR TPDU does not carry a sequence number. Any
previously transmitted TPDUs (including DT and ED) which are
...
... sequence number. Any
previously transmitted TPDUs (including DT and ED) which are
received after the DR TPDU result in a further DR TPDU but are
otherwise ignored. After disconnection, for whatever reason, the
...
... previously transmitted TPDUs (including DT and ED) which are
received after the DR TPDU result in a further DR TPDU but are
otherwise ignored. After disconnection, for whatever reason, the
Reference is placed in the frozen state ...
... Connection Confirm x x x x x 8.4 1101xxxx
DR Disconnect Request x x x x x 8.5 10000000
DC Disconnect Confirm x x x x 8.6 11000000
...
... See Section 8.3.5
8.5 Disconnect Request (DR)
8.5.1 Structure
...