Maintaining Synchronization Between the BGF and the Gateway Controller
The BGF software uses the following features to maintain synchronization between the BGF and the gateway controller:
- Detecting Hanging Terminations
- Detecting Gateway Controller Failures
- Maintaining Synchronization by Auditing Terminations
Detecting Hanging Terminations
Synchronization of termination information between the BGF and the gateway controller is essential for traffic, maintenance, and charging purposes. If a termination does not exchange messages for a period of time, corresponding data for the termination might be mismatched on the BGF and the gateway controller, and the termination can be hanging. Hanging terminations can consume resources that can be used for chargeable calls.
To detect possible hanging terminations, the BGF uses a timer that begins when a message is exchanged for a specific termination. If the termination does not receive a message when the timer expires, the BGF notifies the gateway controller. If the data on the gateway controller does not match the data on the BGF, the gateway controller returns one of the following error messages to the BGF:
Error Code #: 411 Name: The transaction refers to an unknown ContextID Error Code #: 430 Name: Unknown TerminationID Error Code #: 435 Name: Termination ID is not in specified Context
The gateway controller is responsible for correcting mismatches in data. For example, the gateway controller can subtract the indicated termination and clear associated contexts. The gateway controller can also audit the termination service state to check its records before taking further action.
Detection of hanging terminations is described in the following:
- Activating and Configuring Hanging Termination Detection
- Deactivating Hanging Termination Detection
- Displaying the Value of the Timerx Timer Configured on the Virtual BGF
- Displaying the Value of the Hanging Termination Timer for a Termination
Activating and Configuring Hanging Termination Detection
The timerx timer sets the interval between the last message exchanged for a specific termination and when the BGF sends a notification to the gateway controller. The timer resets when a message is exchanged on the termination and when the BGF notifies the gateway controller. For example, if the BGF notifies the gateway controller that there has been no activity on the termination, and the gateway controller does not modify or subtract the indicated termination, the BGF again waits the specified time, and sends another notification if there still has not been activity on the termination.
Setting the timer to a value other than zero (0) activates hanging termination detection on new and modified terminations. The timer value that you set is the default value, and it can be overridden by H.248 messages sent from the gateway controller. To set the timer:
Deactivating Hanging Termination Detection
To deactivate hanging termination detection, set the timerx statement to 0:
Displaying the Value of the Timerx Timer Configured on the Virtual BGF
Purpose
Display the value of the timerx that is configured on the virtual BGF.
Action
[edit services pgcp gateway bgf-1 h248-properties
hanging-termination-detection]user@host# show timerx 30;
Displaying the Value of the Hanging Termination Timer for a Termination
Purpose
Display the timerx value for a termination.
Action
user@host> show services pgcp terminations gateway bgf-1 h248Termination information:
ip/4/vif-0/2 {
MEDIA {
TERMINATIONSTATE { SERVICESTATES = INSERVICE },
STREAM = 1 {
LOCALCONTROL { MODE = SENDRECEIVE, GM/LSP = 0 },
LOCAL {
v = 0,
c=IN IP4 10.50.100.1
m=- 1080 RTP/AVP —
b=AS:0
}
}
}
EVENTS { HANGTERM/THB { TIMERX = 30 } }
}
Detecting Gateway Controller Failures
The BGF supports the inactivity timer package defined in Gateway control protocol: Inactivity timer package H.248.14, March 2002. This feature allows the BGF to detect the failure of its active gateway controller through message inactivity. The inactivity timer is applied to the root terminations of a virtual BGF.
The inactivity timer package specifies a default maximum inactivity time. This timer resets each time the BGF receives a message from the gateway controller. If the BGF does not receive a message from the gateway controller before the maximum inactivity time expires, it sends a Notify message with the observed inactivity timeout event to the gateway controller. If the gateway controller does not reply to the message, the BGF considers the gateway controller as failed.
To configure the inactivity timer package:
- Access the inactivity timeout configuration
for a virtual BGF.[edit services pgcp]user@host# edit gateway bgf-1 h248-properties inactivity-timer inactivity-timeout
- Specify whether the BGF detects inactivity
timeout events received from the gateway controller by default.[edit services pgcp gateway bgf-1 h248-properties inactivity-timer inactivity-timeout]user@host# set detect
- Specify a default value for the maximum
inactivity time. The default value is used if the gateway controller
requests that the BGF detect the inactivity timeout event, but the
gateway controller does not set a value for the maximum inactivity
time.[edit services pgcp gateway bgf-1 h248-properties inactivity-timer inactivity-timeout]user@host# set maximum-inactivity-time default 24000
