Entity Links

Last Updated : Sep 02, 2021 |
Routing entity links connect two SIP entities through the Session Manager to define the network topology for SIP routing. Salient features include:
  • Entity links connect two SIP entities.
  • Trusted Hosts are indicated by assigning the Trust State to the link that connects the entities.
Session Manager uses an entity link to send or receive messages directly from the entity. You must configure an entity link between Session Manager and any administered SIP entity.
To communicate with other SIP entities in the network, each Session Manager instance must identify the port and transport protocol of the entity link to the SIP entities. The Session Manager listens to the local port for connections from the remote entity using the given transport protocol. If the Override Port & Transport option is selected for the SIP entity, Session Manager uses DNS information to determine the port and transport information to the remote entity. If the Override Port & Transport option is not selected for the SIP entity, Session Manager determines the port and transports information to the remote entity using the data administered in the Entity Link table.
Important:
If a SIP entity establishes a connection with a Session Manager before it is configured to trust the SIP entity, the earlier connection remains untrusted. To prevent trust issues:
  • Configure Session Manager before a SIP entity establishes a connection.
  • Use listener ports for endpoints distinct from those used for entity links since, endpoint connections are untrusted and will always be challenged.
  • If a port used for an entity link is modified, the earlier connection should be closed. Restart the security module using the CLI command: restart secmod or reboot the Session Manager to close the earlier connection. Ensure that Session Manager is in maintenance mode and no calls are active before restarting the security module or Session Manager. If that is not possible, restart the far-end SIP entity to re-establish the connections.

Deny new service state

When in the Deny New Service state, entity links do not accept new incoming calls, and Session Manager does not route outgoing calls over these links. Link monitoring continues over these links, but no alarms are generated for the denied links.
When placing an entity link into the Deny New Service state, you can:
  • Take selected SIP Entities out of service for upgrades and repair without receiving numerous SIP Monitoring alarms.
  • Deny the primary link Session Manager uses on a given route to test alternate routing paths.
  • Deny selected links during a planned WAN outage.