LDAP Failure Events

If an incoming session to a primary phone number routed to Lync fails, the phone number is routed to the IP PBX. If failures occur during LDAP queries for all LDAP Servers, the Oracle® Enterprise Session Border Controller logs the failure to the sipdldap.log, and proceeds with normal configured routing policies, if available.

Note:

The Oracle® Enterprise Session Border Controller always establishes the TCP/TLS connection towards the configured LDAP server(s). If a TCP connection fails, the Oracle® Enterprise Session Border Controller continues to attempt to re-establish the connection.

An LDAP connection failure can be due to any one of the following events:

• Oracle® Enterprise Session Border Controller receives a CANCEL message (LDAP connection termination). The Oracle® Enterprise Session Border Controller detects this if it receives or issues an 'unbind' operation. The session is then closed down at TCP/TLS.
• Oracle® Enterprise Session Border Controller receives a call failure message from Lync (TCP/TLS socket termination). If either side receives a finish message (FIN) or reset message (RST), the TCP socket closes per standard behavior, which triggers the LDAP layer to detect connection failure. The Oracle® Enterprise Session Border Controller fails over to a secondary LDAP Server, if configured; otherwise it periodically attempts to reconnect to the Primary LDAP Server.
• Oracle® Enterprise Session Border Controller is unreachable and SIP session towards Lync times out. User is enabled for Lync but the Lync Server is unreachable by the Oracle® Enterprise Session Border Controller so a timeout occurs. When consecutive LDAP queries timeout, the Oracle® Enterprise Session Border Controller concludes that the LDAP session has failed, and then proceeds to terminate the TCP/TLS connection.

The number of consecutive queries that timeout before a connection is considered failed, and the number of successive query timeouts for each LDAP Server can be set via configuration.