Q.931

The Q.931 Recommendation ( Recommandation ) of the ITU -T ( formerly CCITT) describes layer 3 of the Protocol (ISDN user - network interface layer 3 specification for basic call control ) and is used for signaling in ISDN and H.323.

A Q.931 frame is composed of:

Protocol discriminator (PD ), protocol discriminator

Call reference value ( CR) connection detection

Message type (MT) message type

Information element (IE), information elements

ISDN
Network protocol
Switching technology
ITU Recommendation

Integrated Services Digital Network Digital Subscriber System No. 1

666149

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