13. Reference of Call Agent Configuration Parameters

This referecence lists all Call Agent configuration parameters used in ABC SBC. These parameters take effect on any traffic that is specific to a Call Agent without need to place any additional action into the Call Agent’s rulebase.

The actions are grouped as follows:

13.1. Destination Monitor Parameters

These parameters can enable health checks for Call Agents. If enabled, along with blacklisting paramters unresponsive Call Agent’s addresses will be proactively excluded from forwarding.

Parameter Name Description
Monitoring interval (seconds) Interval between sending OPTIONS-based health-checks to the monitored Call Agent. If zero, no monitoring takes place.
Max-Forwards Value of max-forwards header-field in the health-checking OPTIONS requests.

13.2. Blacklisting Parameters

These parameters allow to define for how long a CA’s unresponsive address shall not be used for SIP traffic forwarding (i.e. how long it will be “blacklisted”). See the Section IP Blacklisting: Adaptive Availability Management for additional information.

Parameter Name Description
Blacklist TTL (seconds) Period of time for which an unresponsive address is hold on blacklist. If zero, blacklisting is not used.
Blacklist grace timer (miliseconds) Additional period of time to provide a safety buffer in case that conflicting timers occur along a SIP path.
Blaclist Reply Codes ABC Monitor SIP Response codes which if present in a response will cause placing the downstream SIP server on the blacklist.

13.3. Registration Agent Parameters

Registration agent allows to register the ABC SBC with a third-party SIP service be sending pre-defined REGISTER requests as described in the Section Registration Agent. The following Call Agent paramters define if such a registration agent shall be q active and how its registration parameters shall be formed.

Parameter Name Description
Enabled Turns a registration agent on or off.
URI domain. Domain name to be used in REGISTER requests URIs
URI name. User name to be used in REGISTER request URIs
Display name Display names as included in the From header-field of the REGISTER requests
auth name SIP User id as used in the auhtentication header fields. May be different from user names in URIs.
auth password SIP user password used in the digest authentication
Contact Content of the Contact header-field in the REGISTER requests. Specific usernames may be chosen to make it easier to identify incoming requests coming to addresses reigstered using the registration agent.
Registration interval (seconds) Time between subsequent registrations are sent
Retry interval (seconds) Period of time to keep till the next attempt when the previous failed
Next Hop (IP address) Address of a destination to which a request will be sent
Bulk Contact Turn on to support the SIP bulk contact registration form as described in RFC3680.

13.4. Topology Hiding Parameters

The Section Topology Hiding discussed purpose and use of Topology Hiding. The following options enable/disable this functionality for the respective Call Agents.

Parameter Name Description
Enabled Turning this option replaces occurences of IP addresses in well-known header-fields of SIP signaling with those of the ABC SBC .
Cross-Realm If enabled, toppology hiding is used even when signaling ingress and egress realms are the same.

13.5. Firewall Blacklisting Parameters

Automated IP address blocking is discussed in the Section Automatic IP Address Blocking. Several attributes defined what kind of Call Agent behaviour adds to the score that may eventually lead to blacklisting of the source IP address.

Parameter Name Description
Sanity If turned on, invalid SIP messages add to the auto-blocking score and may lead to blocking of their originator. Otherwise they are silently ignored.
Auth If enabled, failed authentication add to the auto-blocking score and may lead to blocking of their originator. Otherwise only events are reported but no further action is taken.