meta signalling

Meta-signaling is signaling used in ATM/ B-ISDN networks to set up and tear down the signaling channels for the various connections. Similar to ISDN, signaling in B-ISDN takes place in separate user channels.

Since considerably more services and transmission parameters are supported in ATM and B-ISDN than in classic ISDN, correspondingly more signaling processes are required. The signaling known from the D channel has therefore been further developed and exhibits considerably increased flexibility.

The signaling channels are not permanently defined in B-ISDN, but are set up as required by so-called meta-signaling. This is what makes connection types such as point-to-multipoint or multipoint-to-multipoint possible in the first place. Meta-signaling, a type of signaling channel signaling, was defined by the International Telecommunication Union( ITU) under Q.21220. With this signaling, all commands are placed in the ATM cell and sent over a reserved ATM channel.

The meta-signaling fulfills three tasks: the setup, the teardown and the check of the signaling channels. The Q.2931 signaling protocol only becomes active after the connection has been established via a virtual channel( VC) by meta signaling.