Telecontrol Equipment and Systems - Part 6: Telecontrol Protocols Compatible with ISO Standards and ITU-T Recommendations - Section 601: Functional Profile for Providing the Connection-Oriented Transport Service in an End System Connected Via Permanent Access to a Packet Switched Data Network
|Publication Date:||1 December 1994|
|ICS Code (Telecontrol. Telemetering):||33.200|
This Functional Profile (FP) defines the provision of the OS1 Connection-mode Transport Service between an End System ("The Reference End System") which uses a Permanent Analog or Digital Circuit to access a Packet Switched Data Network (PSDN) and another End System ("The Compatible End System") which is accessible, by permanent or switched methods, either directly from the same PSDN, or indirectly through the provided OS1 Connection-mode Network Service.
This FP also defines the provision of the OS1 Connection-mode Network Service between the Reference End System and the Compatible End System using the X.25 subnetwork procedures to a PSDN.
This FP is applicable to environments which support the OS1 Network Service.
In the IS0 taxonomy four options are defined as a function of the transport protocol classes operated:
Group TB: includes transport protocol classes 0.2 and 4,
Group TC: includes transport protocol classes 0 and 2,
Group TD: includes transport protocol class 0,
Group TE: includes transport protocol class 2.
Implementation of the option TD (class O only) requires that the End System does not operate any of the multiplexing classes (class 2, 3, or 4) of the Transport Protocol procedures. Such End Systems will only interwork with End Systems that also implement class O Transport Protocol procedures. Implementation of the other options (groups TB, TC, TE) in one End System, enables that End System to interwork with any End System conforming to IS0 8073.
This FP recommends the implementation of classes O, 2 and 4 in End Systems. In the IS0 taxonomy such End Systems with permanent access to a PSDN are referenced with profiles TBI 11 1 (for analog access) or TB1 121 (for digital access).
NOTE - The FP specifies a set of protocols to be used in the Reference End System in order to provide the function defined above. It does not specify total End System capability. The requirements placed on an End System in this section of IEC 870-6 are solely those necessary for operation of the protocol set specified.
The format of this section is in conjunction with one of the ISO/IEC ISPs.
These ISPs are defined in a multi-part way. For example, to define the profiles TB1111 and TB1121, the present section refers to the three different ISO/IEC ISPs, listed in clause 2.
When applicable the present section follows ISO/IEC ISP 10609-1, ISO/IEC ISP 10609-5 and ISOIIEC ISP 10609-9. The present section defines some complementary specifications to ISP 10609. Those specifications mainly concern the priority management and the transport class negotiation.