When no filtering device drops the packet and it arrives at the destination, the destination host creates an ICMP ECHO _ REPLY packet with the same payload and sends it back as a response message.
22.
Internet based servers'market share can be measured with statistical surveys of publicly accessible servers, such as web servers, mail servers or DNS servers on the Internet : the operating systems powering such servers are found by inspecting raw response messages.
23.
If the response message size is unknown at the time of the call then the more primitive APIs ( BBOA1SRQ ( send request ), BBOA1RCL ( get response length ), BBOA1GET ( get message data ) ) would be more appropriate.
24.
Batch processing narrowly speaking ( processing multiple records through stage, one stage at a time ) is still pervasive in mainframe computing, but is less common in interactive online networked systems, particularly in client server systems such as the request response messages of web servers.
