Network node, entity and methods performed therein for handling a communication session in a communication network

A method performed by an entity of an established communication session for handling a communication session in a communication network using a session description protocol, SDP, for communication sessions, wherein the entity is part in the established session with a network node, the method comprising:

• receiving a request or a response with an indication, wherein the indication indicates a request of one or more mappings of a payload type number to a codec associated to the established session;
• adding a response indication to a response or the received response, wherein the response indication indicates related one or more mappings of a payload type number to a codec of the established session;
• and
• sending, towards the network node, the response with the response indication.

A network node for handling a communication session in a communication network using a session description protocol, SDP, for communication sessions, wherein the network node is configured to connect entities of two established communication sessions with each other, wherein the network node is configured to:

• send, on one or both established communication sessions, a request with an indication, wherein the indication indicates a request of one or more mappings of a payload type number to a codec associated to the communication session;
• receive, over at least one established communication session, a response, wherein the response comprises one or more response indications, wherein a response indication indicates one or more mappings of a payload type number to a codec associated to the communication session;
• and to
• send, to at least one of the entities, a request indication indicating a mapping of a payload type number to a codec suggested to use in an offer message generated by the at least one entity, wherein the mapping is selected based on the one or more response indications in the received response.

An entity of an established communication session for handling a communication session in a communication network using a session description protocol, SDP, for communication sessions, wherein the entity (11) is configured to be part in the established session with a network node, and is further configured to

• receive a request or a response with an indication, wherein the indication indicates a request of one or more mappings of a payload type number to a codec associated to the established session;
• add a response indication to a response or the received response, wherein the response indication indicates related one or more mappings of a payload type number to a codec of the established session;
• and
• send, towards the network node, the response with the response indication.