Method and network node for monitoring a quality of media transfer in a session initiation protocol based voice over internet protocol communications network

A first network node for use in a Session Initiation Protocol (SIP) based Voice over Internet Protocol (VoIP) communications network, the network node comprising:

• a hardware processor, network adapter, and a memory, the memory containing instructions executable by the hardware processor whereby the first network node is configured to:
• update a second network node with quality information representative of a quality of media transfer on a user plane of a first early dialog associated with establishment of a SIP session supporting a particular VoIP call, the updating comprising:
• collecting the quality information;
• detecting a response to a second early dialog associated with the establishment of the SIP session supporting the VoIP call;
• and
• in response to the detecting, transmitting, via the network adapter, a first SIP message comprising the quality information to the second network node;
• wherein the first early dialog is distinct from the second early dialog.

A second network node for use in a Session Initiation Protocol (SIP) based Voice over Internet Protocol (VoIP) communications network, the network node comprising:

• a hardware processor configured to control a network adapter;
• the network adapter;
• a physical storage operatively connected to the hardware processor;
• and
• a memory containing instructions executable by the hardware processor whereby the second network node is configured to:
• transmit, via the network adapter and to a first network node, a response to a second early dialog associated with establishment of a SIP session supporting a particular VoIP call;
• in response to the transmitting, receive, via the network adapter and from the first network node, a first SIP message that includes quality information representative of a quality of media transfer on a user plane of a first early dialog associated with the establishment of the SIP session supporting the particular VoIP call, the first early dialog being distinct from the second early dialog;
• store the quality information in the physical storage.