Simrad ER60, Operator'S Manual

Page: 154 / 182

Simrad ER60 Operator manual
146
850-164692 / Rev.B
Keep connection alive
Once the client application is connected to the server application
a two-way monitoring of the application and communication
”health” must be started. This means that both the client and the
server application must send an ”alive” message,
AliveReport ,
periodically (each second).
AliveReport
The content of the AliveReport message is shown below.
struct AliveReport
{
char Header[4];
// ”ALI\0”
char Info[1024];
// e.g. ”ClientID:1,SeqNo:1\0”
};
The Info field in an AliveReport message from the client to the
server may contain (example):
ClientID:1,SeqNo:1\0
SeqNo
The SeqNo part of the Info field shall contain the sequence
number of the next request message from the client to the server
(the sequence number shall start on 1). The server will use this
to detect if any messages from the client have been lost, if a loss
is detected, the server will issue a retransmit request to the
client.
The AliveReportDef message from the server to the client may
contain (example):
SeqNo:1\0
Similar, the SeqNo part of the Info field shall contain the
sequence number of the next response message from the server
to the client. The client application can use this to detect if any
message from the server is lost, and may then issue a retransmit
request to the server.