Managing Poor Network Connections

Overview:

Feature F-1667 'Ability for GCEMS to handle Satellite Connections to the IMG' allows the IMG to handle unstable connections between the IMG and GCEMS (Host). Communications between GCEMS and the IMG are made using TCP/IP. TCP/IP connections can face drawbacks such as high round trip delays and link errors. High delays and link errors can cause errors when the GCEMS and the IMG pass information between each other. An example of GCEMS to Host communication would be during the configuration process. F-1667 will offer customers with poor network connectivity a smoother Host(GCEMS) to IMG interaction by stopping any unnecessary re-configurations from happening on the IMG. Feature F-1667 continually checks for the link behavior as described below:

Link Up Detection:

Feature F-1667 will begin a timer mechanism upon detecting a 'Link-Up' state between the IMG and GCEMS. The timer value is set by the user. If GCEMS sees that a Link-Up is detected, it will wait the specified amount of time before declaring the link is up. If during this timer period a 'Link Down' state is detected between the IMG and GCEMS, the 'Link Up' state is never passed to the different processes running within GCEMS. If however the timer expires the 'Link Up' state is then passed to the different processes running within GCEMS. The timer described above is used to guard against a burst of connects and disconnects within a short interval of time. See diagram below which displays the Link Up/Link Down Detection scheme.

cf_f-1667_linkup_detection.png

 

Example:

  1. GCEMS starts sending a configuration file to the IMG. The link state is initially in the Link Up state.

  2. The link then changes its state to the Link Down state.

  3. Over the next fifty seconds the network bounces between Link Up state and Link Down state. No information is passed between GCEMS and IMG.

  4. Eventually the network stabilizes. The link state now goes to Link Up state. The LINK_UP_REPORT_TIMER starts and after 50 seconds expires. Since the timer has expired, this indicates that network has now been up for at least 50 seconds. The network is now in a stabile state.

  5. GCEMS will start its re-configuration process. Re-Configuration will depend on the validation of the configuration tags within the IMG.

 

Configuration:

To configure this feature an environment variable will need to be added to the Defaults File. Go to /opt/dialogic/IMG/GateControlEMS/Defaults and using a text editor add the LINK_UP_REPORT_TIMER environment variable shown below. The LINK_UP_REPORT_TIMER value can range from 0-3600 seconds. The default value if this environment variable is not added will be 0. Once this value is set the GCEMS server will need to be reset for the value to hold.

 

# User Overrides Begin

LINK_UP_REPORT_TIMER:60

# User Overrides End

 

LOG_DIR:/opt/dialogic/common/log

STATS_DIR:/opt/dialogic/common/stats

CONFIG_DIR:/opt/dialogic/common/config

LICENSE_DIR:/opt/dialogic/common/license

BACKUP_DIR:/opt/dialogic/common/backup

LLC_SWITCHBACK_MODE:1

LOG_LEVEL:1

STATS_FREQUENCY:5

FILE_MAX_SIZE:25

APP_DISABLED_TIMEOUT:1200

PRODUCT:IMG

 

Additional Information:

Support:

 

Miscellaneous: