| Item | Description |
|---|
SIP Keepalive Messages Configure SIP keepalive messages: | By default, the Edgemarc sends SIP Options messages as a form of keepalive messages to all inactive SIP servers in the SIP server list. |
Enable keepalive messages to all servers | When this box is selected, the Edgemarc will send sends SIP Options messages to the active SIP server in addition to the inactive serverand inactive servers (s).
|
| Enable keepalive messages from all servers | When this option is selected, the Edgemarc determines server reachability status based on the receipt of SIP Options FROM the configured servers in the list . This option is required if the SIP Options Passthrough feature is desired. See ISDN PRI and Survivability for more details on the SIP Options Passthrough feature. | Info |
|---|
| When you select this field, the Enable keepalive messages TO all servers box will be grayed out. |
|
Time Between Keepalive Messages | Enter the number of seconds between consecutive keepalive messages sent to the softswitch to determine connectivity. Note: This field only controls the time between keepalives sent to the servers. When the server is marked unavailable, a backoff algorithm is used for the time interval between keepalives to this server. |
Number of Missed Messages To Declare Alarm | Enter the number of missed messages after which a loss of connectivity to the remote switch is declared. The interval used for these keepalives is the defined initial interval of the regular backoff algorithm, described below. This is 5 seconds by default. |
Number of received messages to clear alarm | Enter the number of consecutively received keepalive messages required for the system to declare successful connectivity to the remote softswitch. |
Interpret error codes as success | Enter the error response codes (maximum of up to 5) to be treated as successful responses (range 300-699). Responses with successful return codes (range 200-299) are always accepted. |
| No-response backoff algorithm | Choose the behavior of keepalive messages when a SIP server becomes unavailable. The following options control the behavior of these keepalive messages when no response is received. Once a response is received, the system resets the interval to the default initial value (5 seconds). • Regular—Keepalive messages to the failed server are started immediately after unavailability is detected. If the system does not receive any response to the keepalive messages, it doubles the interval for the next message until it reaches a maximum. The maximum interval is 40 seconds when in local mode and 160 seconds when in remote mode. • Random—Keepalive messages are not immediately started. The system waits for a random period between 3 seconds and the maximum configured value, Tmax, before starting the OPTIONS pings. If the system does not receive any response to the keepalive messages, it continues to wait for a randomly selected period between 3 seconds and Tmax seconds before sending the next OPTIONS message. |
Maximum backoff interval | Enter the maximum back off interval when you choose the Random option for the No-response back off algorithm. |
Reachability holdoff | Enter the minimum number of seconds to wait after the reachability algorithm detects that a higher priority server has become reachable before marking the server active. This is used to help prevent flip-flopping of the available server when an SBC responds to keepalives but the actual SIP server is not ready to handle registrations. Most installations use a default value of 0 seconds. |
Ignore holdoff when local | Select the checkbox to instruct the system not to apply the Reachability Holdoff delay when the system is running in local mode. This prevents unnecessary delay when switching from local mode to remote SIP servers. |
| SIP Requests |
Monitor SIP Messages | Select the check-box to monitor SIP requests sent to the active server. When this option is selected, the system monitors the SIP requests sent to the active server (excluding keepalive messages generated by the system). If no response is received within the specified time, that server is marked as unavailable. |
Time for declaring SIP messages lost (seconds) | Enter the number of seconds to wait for a reply to a SIP request. If no request is received within this time interval, the softswitch is declared unreachable. |
Monitor Inbound SIP Transactions | Monitors SIP requests from the active SIP server trigger cancellation of the “Monitor SIP Messages” timer. Disabled—The cancellation of the SIP messages timer on request received from active SIP server is disabled. All SIP Requests—Monitor all SIP requests to cancel the SIP messages timer. All except SIP OPTIONS—Monitor all SIP requests except OPTIONS to cancel the SIP messages timer. |
Ignore response codes | Enter response codes that ignore SIP request timeout messages once the Session Border Controller (SBC) has received 100 Trying responses. Enter a comma separated list of response codes. For example, if the list is “100,404,” Survivability ignores a 100 Trying response and 404 Not Found response when determining whether a SIP message has been responded to. |
Ignore other responses when INVITE/NOTIFY pending | Select the check-box to ignore SIP request timeout messages that have an INVITE pending. The Ignore options are useful in environments that have an SBC in the network that responds directly to certain SIP messages. In particular, REGISTER messages are handled by the SBC. Other messages, INVITES in particular, are handled by the SS. In this configuration, the Survivability algorithm might not detect a failure, if the Softswitch went down, but the SBC kept running. It would see responses from the REGISTER messages, but no responses from INVITES. Depending on how they were intermixed, it would at least delay entry into Survivability, and potentially not go into Survivability at all. With the Ignore options set, the Survivability algorithm ignores any response traffic except for non-100 INVITE responses. |
Remote Responses |
Immediate Failover on Remote 4xx 5xx 6xx codes | Specify the SIP error codes that should trigger a proxy switchover. The codes can be any 4xx, 5,xx, or 6xx error. This function provides SIP message response detection for 4xx, 5xx, and 6xx codes based on the current availability of SIP servers . When the active SIP server sends a SIP message response, for example, 500 Server Internal Error or 503 Service Unavailable, the system determines that this SIP server is unavailable and marks its status as Unavailable. The system then marks the Idle SIP server as Active and sends new SIP messages to the Active SIP server until the unavailable SIP server becomes Active. Note that this feature is not dependent on the SIP Keepalive messages or SIP Requests features being enabled; however, it works with both SIP Server Reachability features to provide more reliable SIP server detection of when a SIP server has become unstable for processing SIP calls. Configure 4xx, 5xx, or 6xx Server Failure response messages by a comma delimiter to indicate that a SIP server is currently unavailable , for example, 500,503. | Info |
|---|
| Use caution when configuring the SIP error codes since all response codes may not indicate that the SIP server is unstable for processing SIP calls. For example |
, some 5xx response codes can indicate an issue with the SIP request having an invalid parameter. Configuring a 503 response code may be the correct response code for the solution to indicate that the SIP server has become unstable for processing SIP calls, while a 500 or 501 may indicate an invalid or unsupported parameter in the SIP request. |
|