Network node

A system for use in operating a network node in a network, the system comprising at least one memory including computer program code;

• and
• at least one processor in data communication with the at least one memory, wherein the at least one processor is configured to, at the network node:
• process signaling information for an in-progress communication session dialog according to a stateless operating mode, wherein the processing according to the stateless operating mode comprises storing communication session dialog state data associated with the communication session dialog;
• detect an operating mode change trigger;
• in response to the detection, retrieve the stored communication session dialog state data associated with the communication session dialog;
• and
• process signaling information for the in-progress communication session dialog according to a state-full operating mode, wherein the processing according to the state-full operating mode is carried out at least in part on the basis of the retrieved communication session dialog state data associated with the communication session dialog.

A non-transitory computer-readable storage medium comprising computer-executable instructions which, when executed by a processor, cause a computing device to perform a method of operating a network node in a network, the method comprising, at the network node:

• processing signaling information for an in-progress communication session dialog according to a stateless operating mode, wherein the processing according to the stateless operating mode comprises storing communication session dialog state data associated with the communication session dialog;
• detecting an operating mode change trigger;
• in response to the detection, retrieving the stored communication session dialog state data associated with the communication session dialog;
• and
• processing signaling information for the in-progress communication session dialog according to a state-full operating mode, wherein the processing according to the state-full operating mode is carried out at least in part on the basis of the retrieved communication session dialog state data associated with the communication session dialog.

A method of operating a network node in a network, the method comprising, at the network node:

• processing signaling information for an in-progress communication session dialog according to a stateless operating mode;
• storing communication session dialog state data associated with the communication session dialog;
• detecting an operating mode change trigger;
• in response to the detection, retrieving the stored communication session dialog state data associated with the communication session dialog;
• and
• entering a state-full operating mode in relation to the in-progress communication session dialog, wherein the entering is carried out at least in part on the basis of the retrieved communication session dialog state data associated with the communication session dialog and the entering comprises transmitting at least one communication session dialog update request comprising contact data for the network node.