Media Session

A computer program product comprising code stored on a computer-readable storage medium and configured, when executed on a processor of a first device, to establish a media session between the first device and a second device by implementing the following steps:

• determining at the first device, by exchanging network addresses between the devices:
• (i) a relayed-relayed candidate pair comprising a first media relay server network address available to the first device and a second media relay server network address available to the second device, and (ii) at least one alternative candidate pair comprising a first network address available to the first device and a second network address available to the second device, wherein at least one of those network addresses is a host or reflexive address;
• and
• in response to a session instigation signal at the first device:
• establishing a media session between the devices using the relayed-relayed candidate pair, and performing connectivity checks for at least the alternative candidate pair to determine whether or not the alternative candidate pair is valid;
• wherein the media session is established using the relayed-relayed candidate pair without any connectivity checks having been performed by the devices for the relayed-relayed candidate pair and before the connectivity checks for the alternative candidate pair have been completed;
• and
• wherein if the alternative candidate pair is determined to be valid in the connectivity checks, the established media session is switched to the alternative candidate pair in response.

A first device for establishing a media session between the first device and a second device, the first device comprising:

• a network interface;
• a processor configured to implement the following steps:
• determining at the first device, by exchanging network addresses between the devices:
• (i) a relayed-relayed candidate pair comprising a first media relay server network address available to the first device and a second media relay server network address available to the second device, and (ii) at least one alternative candidate pair comprising a first network address available to the first device and a second network address available to the second device, wherein at least one of those network addresses is a host or reflexive address;
• and
• in response to a session instigation signal at the first device:
• establishing via the network interface a media session between the devices using the relayed-relayed candidate pair, and performing connectivity checks for at least the alternative candidate pair to determine whether or not the alternative candidate pair is valid;
• wherein the media session is established using the relayed-relayed candidate pair without any connectivity checks having been performed by the devices for the relayed-relayed candidate pair and before the connectivity checks for the alternative candidate pair have been completed;
• and
• wherein if the alternative candidate pair is determined to be valid in the connectivity checks, the established media session is switched to the alternative candidate pair in response.