4.2 HTTP KeepAlive Encapsulation Examples

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HTTP KeepAlive encapsulation client creates a full duplex virtual connection that consists of two individual TCP connections. In the following examples, the connections to the server are named GET and POST. The POST connection is used to send data to the server; the GET connection is used to request data from the server. The following figure shows how the KeepAlive encapsulation connection is established.

KeepAlive Encapsulation connection establishment

Figure 24: KeepAlive Encapsulation connection establishment

The following are the messages exchanged to initialize a KeepAlive connection:

KeepAlive-GET-Request:

 ----------------------------------Message START ----------------------------------
 GET /2.0/server.domain.net/kicxp8rrgwqdwhf7c6xsgbagmcdnxm9phtvbj5a,ConnType=KeepAlive HTTP/1.0 
 Accept: */* 
 Content-Type: application/octet-stream 
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Win32) 
 Host: 10.150.1.226 
 Pragma: no-cache 
 Cache-Control: no-cache 
 Expires: 0  
 Connection: Keep-Alive 
 Cache-Control: max-age=0 
  
 ----------------------------------Message END ------------------------------------

KeepAlive-POST-Request:

 ----------------------------------Message START ----------------------------------
 POST /2.0/server.domain.net/kicxp8rrgwqdwhf7c6xsgbagmcdnxm9phtvbj5a,ConnType=KeepAlive HTTP/1.0 
 Accept: */* 
 Content-Type: application/octet-stream 
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Win32) 
 UserAgent: server.domain.net 
 Connection: Keep-Alive 
 Content-Length: 22 
 Pragma: no-cache 
 Cache-Control: no-cache 
 Expires: 0 
 Cache-Control: max-age=0 
  
 GroovePing: 1.0,Ping 
  
 ----------------------------------Message END ------------------------------------

KeepAlive-POST-Response:

 ----------------------------------Message START ----------------------------------
 HTTP/1.0 200 OK 
 Date: Wed, 26 Dec 2007 19:50:26 GMT
 Server: Groove-Relay/12.0
 Connection: Keep-Alive
 Content-Length: 15
  
 <HTML></HTML> 
  
 ----------------------------------Message END ------------------------------------

KeepAlive-GET-Response:

 ----------------------------------Message START ----------------------------------
 HTTP/1.0 200 OK 
 Date: Wed, 26 Dec 2007 19:50:26 GMT 
 Server: Groove-Relay/12.0 
 Connection: Keep-Alive 
 Content-Length: 22 
  
 GroovePing: 1.0,Ping 
  
 ----------------------------------Message END ------------------------------------

For a KeepAlive connection, each request results in a response from the server. The HTTP return codes of 200 on both responses indicates the successful creation of both HTTP connections. The GroovePing message is sent on the POST Request and received on the GET Response to complete the establishment of the virtual KeepAlive connection.

The following figure shows the message flow that is used to send and receive application data between protocol client and protocol server.

HTTP KeepAlive Encapsulation application data exchange

Figure 25: HTTP KeepAlive Encapsulation application data exchange

The following are examples of the messages that are exchanged to send and receive application data between the client and server.

KeepAlive-GET-Request:

 ----------------------------------Message START ----------------------------------
 GET /2.0/server.domain.net/kicxp8rrgwqdwhf7c6xsgbagmcdnxm9phtvbj5a,ConnType=KeepAlive HTTP/1.0 
 Accept: */* 
 Content-Type: application/octet-stream 
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Win32) 
 Host: 10.150.1.226 
 Pragma: no-cache 
 Cache-Control: no-cache 
 Expires: 0 
 Connection: Keep-Alive 
 Cache-Control: max-age=0 
  
 ----------------------------------Message END ------------------------------------

KeepAlive-POST-Request:

 ----------------------------------Message START ----------------------------------
 POST /2.0/server.domain.net/kicxp8rrgwqdwhf7c6xsgbagmcdnxm9phtvbj5a,ConnType=KeepAlive HTTP/1.0 
 Accept: */* 
 Content-Type: application/octet-stream 
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Win32) 
 UserAgent: server.domain.net 
 Connection: Keep-Alive 
 Content-Length: 188 
 Pragma: no-cache 
 Cache-Control: no-cache 
 Expires: 0 
 Cache-Control: max-age=0 
  
 Application-Data    
 ----------------------------------Message END ------------------------------------

KeepAlive-GET-Response:

 ----------------------------------Message START ----------------------------------
 HTTP/1.0 200 OK 
 Date: Wed, 26 Dec 2007 19:50:26 GMT
 Server: Groove-Relay/12.0
 Connection: Keep-Alive 
 Content-Length: 169 
  
 Application-Data
 ----------------------------------Message END ------------------------------------

KeepAlive-POST-Response: 

 ----------------------------------Message START ----------------------------------
 HTTP/1.0 200 OK 
 Date: Wed, 26 Dec 2007 19:50:26 GMT 
 Server: Groove-Relay/12.0 
 Connection: Keep-Alive 
 Content-Length: 0 
  
 ----------------------------------Message END ------------------------------------

KeepAlive-GET-Request:

 ----------------------------------Message START ----------------------------------
 GET /2.0/server.domain.net/g5u55h8rrgwqdwhf7c6xsgbagmcdnxm9pht2kop41a,ConnType=KeepAlive HTTP/1.0 
 Accept: */* 
 Content-Type: application/octet-stream 
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Win32) 
 Host: 10.150.1.226 
 Pragma: no-cache 
 Cache-Control: no-cache 
 Expires: 0 
 Connection: Keep-Alive 
 Cache-Control: max-age=0 
  
 ----------------------------------Message END ------------------------------------