2.2.2.2.6 Method-Key-Value

The METHOD-KEY-VALUE is an RPCKEY and RPCVALUE pair (section 2.2.2.2.5) which specifies the method used by the server.

 METHOD-KEY = RPCKEY 
 METHOD-VALUE = REQUEST-NAME-STRING [":" PROTOCOL-VERSION-STRING]
 METHOD-KEY-VALUE = METHOD-KEY METHOD-VALUE
  
  

The RPC-KEY-STRING (section 2.2.2.2.5) in the RPCKEY of a METHOD-KEY MUST be "method".