HMP Linux 1.2 Release Update, Rev 05 — September 2006 23
The number 6000 is the default value for this parameter. You may change the
beginning of the T.38 service port range by first editing this value and saving the
.config file.
6. After you have saved the .config file with the new T.38 service port value, open the
Command Prompt window.
7. From the Command Prompt, change the directory to /usr/dialogic/data.
8. Execute fcdgen as follows:
/usr/dialogic/bin/fcdgen -f <input filename>.config -o <output
filename>.fcd
The resulting FCD file is created in the /usr/dialogic/data directory. If the -o option is
omitted from the command, the default output FCD file will have the same filename as
the user-modified input .config file, but with an .fcd extension.
9. Restart the system service to download the new configuration to HM P.
H.323 Coder Negotiation with Third Party Stacks
Use caution when restricting coder frame sizes or frames per packet while communicating
with third-party H.323 stacks. The IPT H.323 protocol stack uses both coder type and
frames per packet as part of the algorithm to determine a successful Tx/Rx media match.
Restricting coder frame sizes can cause Fast Start calls to fallback to Slow Star t or coder
negotiation to fail. See the following example.
Example:
A Global Call application configures a channel for G.711 A Law with a frame size of 10
milliseconds. A third-party H.323 stack, which is configured for G.711 A-Law with a
frame size of 30 milliseconds, initiates a call to the application. T he IPT H.323 protocol
stack will use 10 milliseconds as an upper limit for both the Tx and Rx media
directions. Even though both sides support the same coder, the frame size
discrepancy can cause the coder negotiation to fail, resulting in a
GCEV_DISCONNECTED event.
H.323 T.38 HMP Interoperability with the Intel NetStructure® PBX-IP Media Gateway
HMP has not been tested with the current version of the Intel NetStructure PBX-IP Media
Gateway (Version 4.0 Service Update 2) when using H.323 T.38 Fax.
SIP Call Control
If the remote site does not respond to an outgoing INVITE sent from HMP, the
gc_MakeCall() function will time out after 32 seconds and generate a GCEV-
DISCONNECTED event. In this scenario, if the application attempts to drop the call before