Home' RTCA Documents for Review : C2 Link Systems MASPS_Draft Contents Appendix E
© 2018 RTCA, Inc.
Figure E-4: Switchover of the C2 Link System Connection between a Point-to-Point
Link and a Networked Link
We will refer to the Switchover of the Connection from one link to another link, regardless
of whether the links are Point-to-Point links, networked links or a from a Point-to-Point
link to a networked link or vice-versa, as a “C2 Link System Connection Switchover”.
C2 Link System Connection Switchovers require the use of custom commands and
responses (Control Messages) exchanged between the various C2 Link Management
Prior to a Switchover from one link to another link, e.g. , from a terrestrial link to a
SATCOM link, it is assumed that the C2 Link Management Systems have established a
Connection using one of the types of links, e.g., the terrestrial link, and that User Data is
being delivered over this Connection in both directions.
It is also assumed that the C2 Link Management Systems can generate and exchange
Control Messages to perform a C2 Link System Connection Switchover.
For this example, a Switchover from the terrestrial li nk to the SATCOM link is initiated
when an external CS system or the remote pilot, issues a command to execute a Switchover
to the CS C2 Link Management System.
The following describes the Steps required to perform BbM and MbB C2 Link System
Connection Switchovers. These Steps are used in the derivation of the IRs that appear in
Break-before-Make (BbM) Connection Switchover sequence:
1. The CS C2 Link Management System sends an “Initiate Switchover Request”
Control Message to the UA C2 Link Management System over the terrestrial
2. Upon reception of the “Initiate Switchover Request” Control Message over the
terrestrial Connection, the UA C2 Link Management System stops sending User
Data over the terrestrial Connection (one-way terrestrial Connection terminated)
and prepares to establish a SATCOM Connection.
3. The UA C2 Link Management System sends a “Disconnect Request” Control
Message to the CS C2 Link Management System over the terrestrial Connection
and sends a “Connect Request” Control Message to the CS C2 Link Management
System over the SATCOM link.
4. Upon reception of the “Disconnect Request” Control Message the CS C2 Link
Management System responds with a “Disconnect Confirm” Control Message sent
to the UA C2 Link Management System over the terrestrial link; thus, completing
the termination of the terrestrial Connection.
5. Upon reception of the “Disconnect Request” over the terrestrial Connection, the
CS C2 Link Management System stops sending User Data over the terrestrial
Connection (two-way terrestrial Connection terminated).
6. Upon reception of the “Connect Request” message over the SATCOM link, the CS
C2 Link Management System responds with a “Connect Confirm” message sent
to the UA C2 Link Management System over the SATCOM Connection.
7. Upon reception of the “Connect Confirm” message, the UA C2 Link Management
System starts sending User Data over the SATCOM Connection, thus completing
the successful establishment of a two-way SATCOM Connection.
Links Archive DO-XYZ_ED-ABC_FRAC_SC236_MASPS Navigation Previous Page Next Page