# Table of Contents 1. [Packet Format](#orgb2a43d1) 2. [Common Header](#org5ca4c69) 1. [Types](#org240efb3) 2. [Shared Flags](#org804fcce) 3. [Handshake Packet](#org6a73ea8) 4. [Forward Packet](#org39c753e) 1. [Flags](#org5177d26) 2. [Payload](#orgb29cbd7) 1. [Message Content map structure](#org75acfe6) 5. [Heartbeat Packet](#org388b69a) # Packet Format
 bytes    0     1     2     3           5             6 .. end    
            variable length       common header       payload     
The length of the remaining part(common header + payload) is indicated by the Length Header of each packet # Common Header
 bits    0     1     2     3     4     5     6     7  
             packet type            shared flags      
## Types
   type       usage   
    0       handshake 
    1        forward  
    2       heartbeat 
## Shared Flags The usage of each bit is determined by the type of packet # Handshake Packet
 bytes         0               1       
         common header      version    
# Forward Packet
 bits   0   1   2   3   4   5   6    7       ...    
      
      
       		               
  packet type  
                		             ACK             
  payload  
           
  forward flags  
## Flags
 flag                     usage                   
 ACK         This packet need a ACK response      
## Payload
 bytes    0     ..      n    n+1   ..     x  
          Content Length     Message Content 
- Content length is a variable length number. - Message content is a list in an opaque binary format whose element is a map structure ### Message Content map structure { id: "0006081CCFF3D48F03C10000058B0000", // unique message id qos: 1, flags: {dup: false, retain: false}, from: "clientid", topic: "t/1", payload: "hello, world", timestamp: 1697786555281 } # Heartbeat Packet
 bytes         0       
         common header