The Tethering Control Channel Protocol is initialized after the transport protocol has created a communication channel with the server. After the communication channel is initialized, the client sends a BringUpStartRequest message (section 22.214.171.124) to the server. If the client is not paired to the server, the BringUpStartRequest MUST contain the optional HMAC and Timestamp fields. The client SHOULD<6> include the HMAC and Timestamp fields regardless of pairing relationship. Providing the HMAC and Timestamp field regardless of pairing state provides resiliency when the server has broken the pairing relationship without the client’s knowledge.