The following figure is an example of the connectivity and protocols for a Metasys system using multiple engines and an ADS. Table 1 describes the protocols used in Figure 1.
Figure 1. Metasys System with Multiple Engines and an ADS
|
Interaction between callouts |
Protocol |
Communication direction |
|
|---|---|---|---|
|
1 |
2,3,5 |
HTTP |
Unidirectional |
|
1 |
4 |
Customer standard configuration |
Customer standard configuration |
|
2 |
3,5 |
HTTP |
Bidirectional |
|
2,3,5 |
4 |
DHCP, DNS, SMTP, SNMP, SNMP Trap, SNTP |
Unidirectional |
|
3,5 |
2 |
SNTP |
Unidirectional |
|
3,5 |
3,5 |
HTTP, BACnet, DNS |
HTTP, BACnet: Bidirectional DNS: Unidirectional |
1 In Unidirectional communication, only the
originating device initiates requests (assuming synchronous
response is allowed in the request).
2 To ensure proper
performance, a Web browser should never use an engine for
its SNTP server.