Codec negotiation

A method of interworking Circuit Switched (CS) video calls with video calls using IP multimedia protocols, the method comprising end-to-end codec negotiation, wherein the end-to-end codec negotiation comprises:

• at an interworking function, receiving signaling comprising an indication of the codec capability of a CS terminal involved in the CS video call, as part of a MONA negotiation;
• and
• thereafter initiating IP codec negotiation.

Apparatus for enabling interworking of Circuit Switched (CS) video calls with video calls using IP multimedia protocols, the apparatus being arranged to support end-to-end codec negotiation, wherein the apparatus is arranged to:

• receive signaling comprising an indication of the codec capability of a CS terminal involved in the CS video call, as part of a Media Oriented Negotiation Acceleration (MONA) MONA negotiation;
• and
• thereafter initiate IP codec negotiation.

A terminal for use in a telecommunication system, the terminal being able to support a Media Oriented Negotiation Acceleration (MONA) Signaling Preconfigured Channel (SPC) MONA, wherein the terminal comprises means for preventing, delaying or inhibiting a fallback to a call establishment mechanism other than SPC, at least for a first period of time, under specified conditions, wherein the fallback would not be prevented, delayed or inhibited in the absence of said means.

A terminal for use in a telecommunication system, the terminal being able to support Media Oriented Negotiation Acceleration (MONA) Signaling Preconfigured Channel (SPC), wherein the terminal is arranged, when one or more first conditions are met, to cause, initiate or perform a fallback to a call establishment mechanism other than SPC, wherein the terminal comprises means for preventing, delaying or inhibiting a said fallback, at least for a first period of time, when one or more second conditions are met despite said one or more first conditions being met.

A terminal for use in a telecommunication system, the terminal being able to support Media Oriented Negotiation Acceleration (MONA) Signaling Preconfigured Channel (SPC), wherein, when one or more conditions are met, the terminal is arranged to initiate fallback to a call establishment mechanism other than SPC, wherein the terminal is arranged not to initiate the fallback, at least for a first period of time, when it has received a valid MOS requestAck message.

A method of operating a terminal for use in a telecommunication system, the terminal being able to support a Media Oriented Negotiation Acceleration (MONA) Signaling Preconfigured Channel (SPC), wherein the method comprises:

• the terminal causing, initiating or performing a fallback to a call establishment mechanism other than SPC when one or more first conditions are met, and
• the terminal preventing, delaying or inhibiting a said fallback, at least for a first period of time, when one or more second conditions are met despite said one or more first conditions being met.

A method of operating a terminal for use in a telecommunication system, the terminal being able to support a Media Oriented Negotiation Acceleration (MONA) Signaling Preconfigured Channel (SPC), wherein, when one or more conditions are met, the terminal is arranged to initiate fallback to a call establishment mechanism other than SPC, wherein the method comprises:

• the terminal not initiating the fallback, at least for a first period of time, when it has received a valid MOS requestAck message.