Administratively Disabling a SIP Registrar

The Oracle® Enterprise Session Border Controller's registration cache feature is commonly used to support authorization. It also allows the Oracle® Enterprise Session Border Controller to respond directly to SIP REGISTER requests from endpoints rather than forwarding every REGISTER message to the Registrar(s). In the Oracle® Enterprise Session Border Controller, Registrars are frequently configured as session agents, and an association between each endpoint and its Registrar is stored with the registration cache information.

In Release 4.0.1 and later, the invalidate-registrations parameter in the session agent configuration enables the Oracle® Enterprise Session Border Controller to detect failed Registrar session agents and automatically forward subsequent REGISTER requests from endpoints to a new Registrar. You can now perform the same behavior manually through a new ACLI command. When you use this command, the Oracle® Enterprise Session Border Controller acts as though the registrations have expired.

For each SIP session agent, you can enable the manual trigger command, and then use the command from the main Superuser ACLI prompt. The reset session-agent command provides a way for you to send a session agent offline. Session agents can come back online once they send 200 OK messages the Oracle® Enterprise Session Border Controller receives successfully.

Without using the manual trigger, session agents can go offline because of they do not respond to pings or because of excessive transaction timeouts. However, you might not want to use these more dynamic methods of taking session agents out of service (and subsequently invalidating any associated registrations). You can disable both of these mechanisms by setting the following parameters to 0:

ping-interval—Frequency (amount of time in seconds) with which the Oracle® Enterprise Session Border Controller pings the entity the session agent represents)
ttr-no-response—Dictates when the SA (Session Agent) should be put back in service after the SA is taken OOS (Out Of Service) because it did not respond to the Oracle® Enterprise Session Border Controller

However, you can still use the new SIP manual trigger even with these dynamic methods enabled; the trigger simply overrides the configuration to send the session agent offline.

Considerations for Implicit Service Route Use

When implicit service route support is enabled for a SIP interface (in IMS applications), the Oracle® Enterprise Session Border Controller stores the Service Route URIs from the Service-Route headers that are included in 200 OK responses to REGISTER messages. Subsequently, and even when a session agent is rendered invalid, re-REGISTER messages follow the route stored in the cache instead of using the one defined in the Oracle® Enterprise Session Border Controller.

However, you might not want to use this behavior when you send session agents offline. If you instead want use the route defined in the Oracle® Enterprise Session Border Controller, then you need to configure the SIP interface option called route-register-no-service-route.

Manual Trigger Configuration

This section shows you how to enable the manual trigger for sending session agents out of service, and how to then use the trigger from the command line. This section also shows you how to verify that you have successfully put a session agent out of service.

To enable a SIP session agent to manually trigger it to go out of service:

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
ORACLE(configure)#
```
Type session-router and press Enter to access the signaling-level configuration elements.
```
ORACLE(configure)# session-router
ORACLE(session-router)#
```
Type session-agent and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(session-router)# session-agent
ORACLE(session-agent)#
```
If you are adding support for this feature to a pre-existing configuration, then you must select (using the ACLI select command) the configuration you want to edit.
invalidate-registrations—Set this parameter to enabled if you want to use the manual trigger to send this session agent offline (and therefore invalidate the registrations associated with it). The default is disabled.
Save and activate your configuration.

To use the manual trigger that sends session agents offline:
Note the hostname value (typically the IP address of the endpoint) for the session agent you want to put out of service. You use this name as an argument in the ACLI command to use the manual trigger.
At the Superuser prompt, type reset session-agent, a Space, and the hostname value for the session agent. The press Enter.
```
ORACLE# reset session-agent 192.168.20.45
```
If you enter a session agent that does not exist, the system notifies you that it cannot carry out the reset.

Manual Trigger Confirmation

To confirm that a session agent has been sent offline:

Use the show sipd endpoint-ip command to confirm the session agent state.

ACMEPACKET# show sipd endpoint-ip 1016
User <sip:1016@172.18.1.80>
		Contact exp=3582
			UA-Contact: <sip:1016@192.168.1.132:5060> UDP
				realm=access local=172.18.1.132:5060
UA=192.168.1.132:5060
	SD-Contact: <sip:1016-o3badgbbnjcq5@172.18.2.80:5060> realm=core
	Call-ID: 1-7944@192.168.1.132’
	SR=172.18.2.92												
	SA=172.18.2.93
	Service-Route='<sip:test@s-cscf::5060;orig;lr>'
ACMEPACKET# reset session-agent 172.18.2.92
Accepted
Reset SA failover timer
ACMEPACKET# show sipd endpoint-ip 1016
User <sip:1016@172.18.1.80>
		Contact <invalidated> exp=3572
			UA-Contact: <sip:1016@192.168.1.132:5060> UDP
				realm=access local=172.18.1.80:5060
UA=192.168.1.132:5060
	SD-Contact: <sip:1016-o3badgbbnjcq5@172.18.2.80:5060> realm=core
	Call-ID: 1-7944@192.168.1.132’
	SR=172.18.2.92 (failed 2 seconds ago)				
	SA=172.18.2.93
	Service-Route='<sip:test@s-cscf::5060;orig;lr>'
ACMEPACKET#

In the above ACLI example the first iteration of the show sip endpoint-ip command provides information for the in-service 172.18.2.92 session agent; the second command iteration displays information for the now out-of-service session agent.