Followed by a UTF-8 Encoded String which is used as the basis for creating a Response Topic. The way in which the Client creates a Response Topic from the Response Information is not defined by this specification. It is a Protocol Error to include the Response Information more than once. If the Client a Request Response Information with a value 1, it is OPTIONAL for the Server to send the Response Information in the CONNACK. Non-normative comment A common use of this is to pass a globally unique portion of the tree which is reserved for this Client for at least the lifetime of its Session. This often cannot just be a random name as both the requesting Client and the responding Client need to be authorized to use it. It is normal to use this as the root of a topic tree for a particular Client. For the Server to return this information, it normally needs to be correctly configured. Using this mechanism allows this configuration to be done once in the Server rather than in each Client. Refer to section 4.10 for more information about Request / Response. Server Reference 28 (0x1C) Byte, Identifier of the Server Reference. Followed by a UTF-8 Encoded String which can be used by the Client to identify another Server to use. It is a Protocol Error to include the Server Reference more than once. The Server uses a Server Reference in either a CONNACK or DISCONNECT packet with Reason code of 0x9C (Use another server) or Reason Code 0x9D (Server moved) as described in section 4.13. Refer to section 4.11 Server redirection for information about how Server Reference is used. Authentication Method 21 (0x15) Byte, Identifier of the Authentication Method. Followed by a UTF-8 Encoded String containing the name of the authentication method. It is a Protocol Error to include the Authentication Method more than once. Refer to section 4.12 for more information about extended authentication. Authentication Data 22 (0x16) Byte, Identifier of the Authentication Data. Followed by Binary Data containing authentication data. The contents of this data are defined by the authentication method and the state of already exchanged authentication data. It is a Protocol Error to include the Authentication Data more than once. Refer to section 4.12 for more information about extended authentication. CONNACK Payload The CONNACK packet has no Payload.
Followed by a UTF-8 Encoded String which is used as the basis for creating a Response Topic. The way in which the Client creates a Response Topic from the Response Information is not defined by this specification. It is a Protocol Error to include the Response Information more than once. If the Client a Request Response Information with a value 1, it is OPTIONAL for the Server to send the Response Information in the CONNACK. Non-normative comment A common use of this is to pass a globally unique portion of the tree which is reserved for this Client for at least the lifetime of its Session. This often cannot just be a random name as both the requesting Client and the responding Client need to be authorized to use it. It is normal to use this as the root of a topic tree for a particular Client. For the Server to return this information, it normally needs to be correctly configured. Using this mechanism allows this configuration to be done once in the Server rather than in each Client. Refer to section 4.10 for more information about Request / Response. Server Reference 28 (0x1C) Byte, Identifier of the Server Reference. Followed by a UTF-8 Encoded String which can be used by the Client to identify another Server to use. It is a Protocol Error to include the Server Reference more than once. The Server uses a Server Reference in either a CONNACK or DISCONNECT packet with Reason code of 0x9C (Use another server) or Reason Code 0x9D (Server moved) as described in section 4.13. Refer to section 4.11 Server redirection for information about how Server Reference is used. Authentication Method 21 (0x15) Byte, Identifier of the Authentication Method. Followed by a UTF-8 Encoded String containing the name of the authentication method. It is a Protocol Error to include the Authentication Method more than once. Refer to section 4.12 for more information about extended authentication. Authentication Data 22 (0x16) Byte, Identifier of the Authentication Data. Followed by Binary Data containing authentication data. The contents of this data are defined by the authentication method and the state of already exchanged authentication data. It is a Protocol Error to include the Authentication Data more than once. Refer to section 4.12 for more information about extended authentication. CONNACK Payload The CONNACK packet has no Payload.
mqtt-v5.0-csprd01.docx