tokens: ['The', 'CS', 'Proxy', 'is', 'responsible', 'for', 'CSK', 'key', 'management', 'Hence', 'should', 'the', 'CSK', 'require', 'renewal', 'the', 'CS', 'Proxy', 'will', 'create', 'and', 'send', 'a', 'key', 'download', 'message', 'to', 'the', 'MC', 'client', 'containing', 'the', 'new', 'CSK', 'This', 'functionality', 'is', 'as', 'currently', 'defined', 'for', 'a', 'MCX', 'Server', 'As', 'signalling', 'proxies', 'may', 'present', 'the', 'one', 'or', 'multiple', 'SIP', 'URIs', 'externally', 'the', 'same', 'client', 'may', 'attempt', 'to', 'connect', 'to', 'the', 'same', 'CS', 'Proxy', 'twice', 'using', 'different', 'URIs', 'and', 'CSKs', 'each', 'time', 'In', 'this', 'scenario', 'the', 'CS', 'Proxy', 'may', 'remove', 'CSK', 'ambiguity', 'by', 'using', 'the', 'CSK', 'key', 'download', 'procedure', 'as', 'follows', '', 'The', 'MC', 'client', 'connects', 'to', 'the', 'CS', 'Proxy', 'using', 'the', 'URI', 'A', 'The', 'MC', 'client', 'provides', 'CSKA', '', 'The', 'CS', 'Proxy', 'receives', 'CSKA', 'and', 'the', 'MC', 'client', 'and', 'CS', 'Proxy', 'use', 'CSKA', 'to', 'protect', 'application', 'signalling', '', 'The', 'MC', 'client', 'connects', 'to', 'the', 'CS', 'Proxy', 'using', 'the', 'URI', 'B', 'The', 'MC', 'client', 'provides', 'CSKB', '', 'The', 'CS', 'Proxy', 'observes', 'that', 'the', 'same', 'client', 'has', 'connected', 'again', 'using', 'a', 'different', 'URI', '', 'The', 'CS', 'Proxy', 'performs', 'a', 'CSK', 'key', 'download', 'to', 'update', 'CSKB', 'The', 'CS', 'Proxy', 'sets']