GE PACSystems RX7i, User Manual

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Chapter 7. Programming SRTP Channel Commands
GFK-2224Q January 2017 133
If the COMMREQ status word is updated to 1, the Command Block was processed successfully by the Ethernet
Interface.
If the COMMREQ status word is updated to a value other than 1, an error has occurred in processing the
Command Block. The cause may be:
▪
Errors in the Command Block (the Channel command code or parameters), or
▪
For an establish command (Establish Read Channel, Establish Write Channel, or Send Information Report),
the command parameters were valid but there was an error in establishing a channel.
Chapter 11 lists the Major and Minor error codes that may be returned in the COMMREQ status words. Do not
use data received from a server until the COMMREQ status word for that channel is 1 or the Data Transfer bit
goes to 1.
Differences between Series 90 and PACSystems SRTP Channels
This section lists differences between the Series 90 implementation of SRTP Channels and the PACSystems
implementation.
1.
The TCP Connect Timeout for an SRTP Channel on the Series 90 was 90 seconds. For PACSystems, a new
SRTP AUP parameter, “SRTP Channel TCP Connect Timeout”, will be added that specifies the amount of
time to wait for a TCP connection to be established: hconn_tout. The default value will be set to 75
seconds, and its maximum value is 75 seconds, which is the maximum value we can specify to the current
OS. Minimum value is 10 milliseconds.
2. PACSystems has a TCP Linger Period, which is the period of time the OS Network stack hangs onto the TCP
resources associated with a connection after it is closed. The TCP resources from a channel that was
stopped will become available again after the 60 second TCP linger period has expired. The Series 90 had
no linger period.
3. The Series 90 SRTP Channel implementation performed a normal stopping of the channel on a Run-to-Stop
transition. On PACSystems, a Run-to-Stop transition causes an Abrupt Shutdown, avoiding the TCP Linger
period and reducing the chance of exhausting TCP resources when quickly transitioning between Run-
>Stop and Stop->Run.
4. On the Series 90, if an Abort/Abort All Channel COMMREQ is issued, followed by an Establish
Read/Write/Send Info Report Channel COMMREQ before the COMMREQ Status Word for the Abort/Abort All
has been updated, the Establish Read/Write/Send Information Report was dropped and the COMMREQ
Status Word was not updated (it remained zero). For PACSystems, the Establish Read/Write/Send
Information Report COMMREQ is discarded and its COMMREQ Status Word is set to a failure value (A990).
That indicates it was discarded because the application logic issued the command while an Abort was in
progress.
5. For PACSystems, new COMMREQ Status Codes are defined. See Chapter 11 for details.
6. The PACSystems implementation supports Re-tasking to a different remote device (different IP Address).
7. The Series 90-70 limited the total number of TCP connections shared between SRTP Client Channels and
SRTP Server to 48. TCP connections not shared between SRTP Server and Client, and the maximum TCP
Connections allowed for PACSystems are increased as follows:
a. maximum of 48 Server TCP connections for Rack-based and RX7i Embedded
19
b. maximum of 32 Client Channel TCP connections
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8. CPE330 Embedded Ethernet Interface supports 48 SRTP server connections and 32 client channels.
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32 SRTP server connections for RX3i Embedded Ethernet interface
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16 Client Channel connections for RX3i Embedded Ethernet interface