Patent ID: 8037196

Claim:
A method comprising a sending device performing steps of: maintaining a protocol register containing a first and second protocol; using the first protocol, and without knowing in advance whether a peer device is using the first protocol, attempting delivery of a message to the peer device; determining that the message was not successfully received by the peer device, thereby indicating that the peer device is using a protocol inconsistent with the first protocol; and responsive to determining the message was not successfully received by the peer device, retrieving the second protocol from the protocol register; and without knowing in advance whether the peer device is using the second protocol, attempting delivery of a message from the sending device to the peer device using the second protocol; wherein the step of maintaining a protocol register comprises: storing, in a first register of the sending device, a current protocol; storing, in a second register of the sending device, a previous protocol; and upon the sending device receiving a new protocol, in the first register, replacing the current protocol with the new protocol, the new protocol defining the first protocol and the current protocol defining a former current protocol; in the second register, replacing the previous protocol with the former current protocol, the former current protocol defining the second protocol.