Steering Pool Port Allocation
Every steering pool you create includes its own range of ports for media flows. The total number of ports in all the steering pools that feed into one realm are available for calls in and out of the realm.
Steering pool ports for a given realm are assigned to media flows sequentially. When the first call enters the Oracle® Enterprise Session Border Controller after start-up, it is assigned the first ports on the first steering pool that you configured. New calls are assigned to ports sequentially in the first steering pool. When all ports from the first steering pool are exhausted, the Oracle® Enterprise Session Border Controller uses ports from the next configured steering pool. This continues until the last port on the last configured steering pool is used.
After the final port is used for the first time, the next port chosen is the one first returned as empty from the full list of ports in all the steering pools. As media flows are terminated, the ports they used are returned to the realm’s full steering pool. In this way, after initially exhausting all ports, the realm takes new, returned, ports from the pool in a least last used manner.
When a call enters the Oracle® Enterprise Session Border Controller, the signaling application allocates a port from all of the eligible steering pools that will be used for the call. Once a port is chosen, the Oracle® Enterprise Session Border Controller checks if the steering pool that the port is from has a defined network interface. If it does, the call is set up on the corresponding network interface. If a network interface is not defined for that steering pool, the network interface defined for the realm is used.