Patent ID: 9565216
Date: 2017-02-07
CPC Classifications: H04L,H04W

Claim:
1. A method, comprising: receiving, at a registration server in an internet protocol multimedia subsystem network, a security protocol identification message from user equipment, wherein the security protocol identification message identifies a list of security protocols supported by the user equipment and comprising a first security protocol, a second security protocol, and a third security protocol, which are ordered by preference, with the first security protocol being indicated as more preferred relative to the second security protocol by the user equipment, wherein the security protocol identification message is received prior to receiving a first secured registration request message from the user equipment; sending, prior to receiving the first secured registration request message from the user equipment, a message from the registration server to the user equipment proposing the first security protocol; receiving, at the registration server in the internet protocol multimedia subsystem network, the first secured registration request message from the user equipment, wherein the first secured registration message is secured using the first security protocol, wherein the first secured registration request message is received from the user equipment at the registration server in response to sending the message from the registration server to the user equipment proposing the first security protocol; determining, at the registration server, that the first secured registration request message cannot be decoded using the first security protocol; determining, based on the list of security protocols that includes the first security protocol, the second security protocol, and the third security protocol, that the third security protocol is associated with a greater probability of successful registration of the user equipment than the second security protocol even though the second security protocol is preferred by the user equipment over the third security protocol; sending, to the user equipment, a message from the registration server proposing the third security protocol; and receiving, at the registration server, a second secured registration request message from the user equipment, wherein the second secured registration request message is secured using the third security protocol.