Device and method for the packet based access of classical ISDN/PSTN subscribers to a switching system
View Patent ↗The invention relates to a device and to a method for the packet-based access of classical ISDN/PSTN subscribers to a switching system. The convergence of packet-based networks and TDM networks leads to a situation where classical analogous and ISDN subscribers and private branch exchanges have to be accessed via packet-based transmission methods. Especially for the case of a failure of, for example, the subscriber terminals TNE or switching system-related devices or intervening communication paths, it must be made sure that substitute connections can be made and stable connections can be maintained. This problem is solved by the present invention by providing a peripheral adaptation device, integrated into the periphery of the switching system, and being suitable for the adaptation of the messages used on the interface between subscriber terminal and peripheral adaptation device, to the requirements of the plurality of peripheral devices associated with the TNE port. Furthermore, software functions are provided for treating the failure of, for example, the subscriber terminal, the one peripheral adaptation device or one of the associated peripheral devices of the switching system. The interaction of said failure treatment software functions controls the substitute connection and restart of failed peripheral devices, peripheral adaptation devices and communication paths to subscriber terminals.
1. Method for connecting conventional analog and ISDN subscribers to a switching system, with the subscriber signaling between a subscriber terminal device (TNE) and the switching system being transmitted, packet-based, via a network and with a plurality of such subscribers being assigned in each case to a common set of peripheral devices (PE) of the switching system, characterized in that,
at least one peripheral adaptation device (PAE) is provided, that is arranged in the periphery of the switching system and is used for the adaptation of the messages used on the interface between the subscriber terminal device (TNE) and peripheral adaptation device (PAE) serves the requirements of the set of peripheral devices (PE) assigned to the TNE port, software functions for dealing with failures in the subscriber terminal device (TNE) of at least one peripheral adaptation device (PAE) and the associated peripheral devices (PE) of the switching system are provided,
due to the interaction of these software functions for dealing with failures the alternative routing and restoration of failed peripheral devices (PE), peripheral adaptation devices (PAE) and communication paths to subscriber terminal devices (TNE) are controlled.
2. Method in accordance with claim 1 , characterized in that,
in the event of loss of communication via a peripheral adaptation devices (PAE) communication via a further peripheral adaptation device (PAE) is established from the subscriber terminal device (TNE).
3. Method in accordance with claim 1 , 2 , characterized in that,
in the event of failure of communication via all the peripheral adaptation devices (PAE) assigned to it, the subscriber terminal device (TNE) cyclically attempts to establish communication via a further peripheral adaptation device (PAE), the associated switching resources are released and the activated switching of user data flows of their connections are terminated.
4. Method in accordance with claims 1 to 3 , characterized in that,
the failure and the restoration of availability of a connection at the subscriber terminal device is signaled to the switching system by the subscriber terminal device (TNE) via the communication with the peripheral adaptation device (PAE) and the picture of the status of a connection is held in the exchange and the switching availability of the connection is described in the switching system.
5. Method in accordance with claim 4 , characterized in that,
the MGCP protocol or H.248 is used to signal the status of a connection at the subscriber terminal device (TNE) to the switching system.
6. Method in accordance with one of the preceding claims, characterized in that,
the connections reported at the subscriber terminal device (TNE) as failed are cyclically checked by the peripheral adaptation device (PAE) for restoration of availability.
7. Method in accordance with claim 6 , characterized in that,
the MGCP protocol or H.248 is used to check the status of a connection at the subscriber terminal device (TNE) by means of the peripheral adaptation device (PAE) of the switching system.
8. Method in accordance with one of the preceding claims, characterized in that,
connections at the subscriber terminal device (TNE) that are active with regard to switching are cyclically checked for availability by the peripheral adaptation device (PAE), and if non-availability is determined, the switching and transactions are cleared down and the call charge metering for the relevant connection is stopped in the exchange.
9. Method in accordance with claim 8 , characterized in that,
the MGCP protocol or H.248 is used for checking the active switching connections at the subscriber terminal device (TNE) by means of the peripheral adaptation device (PAE) of the switching system.
10. Method in accordance with one of the preceding claims, characterized in that,
in the event of failure of peripheral adaptation devices (PAE), stable connections are maintained by the redundant storage of switching states in a redundant peripheral adaptation device (PAE) or by recovery of the switching states by interrogating the participating subscriber terminal devices and media gateways after switching to a further peripheral adaptation device (PAE).
11. Method in accordance with one of the preceding claims, characterized in that,
in the event of failure of a peripheral device (PE), the through switching of connections that can no longer be operated is dealt with by utilizing the storage of the switching states in the peripheral adaptation devices (PAE) or by recovery of the switching states by interrogating the participating subscriber terminal devices and media gateways.
12. Method in accordance with claim 10 or 11 , characterized in that,
the MGCP protocol or H.248 is used for the recovery of the switching states by interrogating the participating subscriber terminal devices (TNE) and media gateways.
13. Method in accordance with one of the preceding claims, characterized in that,
the failure of a subscriber terminal device (TNE) is detected by cyclic communication attempts of a peripheral adaptation device (PAE) and the non-availability of the associated connections is depicted.
14. Method in accordance with one of the preceding claims, characterized in that,
ports of a subscriber terminal device used in the switching system as connections not available for switching are not used even for terminating calls.