Virtual Call Signaling Address
You can configure the Oracle® Enterprise Session Border Controller with:
- A TCP port range for Q.931—Q.931 ports that are frontend ports handled by a real backend socket, and are therefore virtual
- ATCP port range for separate H.245 TCP connections—Actual sockets that the Oracle® Enterprise Session Border Controller handles separately
Virtual call signaling address is an H.323 call signaling address that is registered with a gatekeeper, but does not have a corresponding listening socket in the Oracle® Enterprise Session Border Controller. Using the virtual call signaling address means that numerous network transport addresses do not need to be allocated.
Virtual call signaling addresses work by attaching a range of TCP server ports to a single listening TCP socket. After a connection is accepted, the accepting socket created by the server socket operated normally, as though it were created by the server socket that listens on the same transport address as the destination of the arriving packet.
To use virtual call signaling addresses, you specify a Q.931 port range from which the Oracle® Enterprise Session Border Controller can allocate ports. This port range is associated with the virtual call signal IPv4 address you specify. To bind dynamic TCP connections to aport within a port range, you configure a dynamic H.245 port range. The dynamic H.245 port range refers to the separate TCP connection for H.245 that takes place when tunneling is not being used. This enables the Oracle® Enterprise Session Border Controller to select the port to which the TCP socket is bound. These two port ranges cannot overlap.
When a new RRQ has to be forwarded to the gatekeeper, the Oracle® Enterprise Session Border Controller caches the registration and then forwards a modified copy of the RRQ. The Oracle® Enterprise Session Border Controller allocates a virtual call signal address on the gateway stack and uses it to replace the CSA of the registering endpoint in the forwarded RRQ.
