Specifications

Working with a Distributed Server Architecture
PlantScape Server and Client Configuration Guide 349
Accessing history data for remote points in real time might impact the overall
performance of a low bandwidth network, such as a WAN. For example, history
data trend displays is requested and returned in real time.
Multicasting
For any server in the distributed architecture, you can choose multicasting to
remote servers that are connected over a network that supports it. The
performance effects of multicasting depend on the network and the number of
servers. Contact your local Honeywell representative for information about the
network devices that support multicasting, and its appropriateness for your
system.
When multicasting is used, a server sends a single copy of its data over the
network to other servers. The other servers on the network need to know the
network address and port number the multicast packets use so that the
networking software can listen for data on that address. The benefit of
multicasting is to conserve bandwidth and reduce network traffic.
Some routers are not configured with multicasting enabled. In this situation
multicasting must be manually enabled on the router.
PlantScape uses multicasting to provide the status of both the server and the links
between servers in a distributed server architecture. Each server has a link
daemon which multicasts its status to the network. Daemons on the other servers
listen for these multicasts to obtain the status of other servers.
Synchronization Considerations
To share alarms and historical data, the servers need to be time synchronized.
However, the servers can be in different time zones, each showing its own local
time.
For information about how to synchronize servers, refer to “Re-Synchronizing the
Date and Time on the Servers” on page 315.
Server Redundancy and Networks
No special configuration is required for Distributed Server Architecture on
redundant server systems or dual network systems. The Distributed Server status
summary and status tabs show the redundancy architecture of each server.
plscpcg.book Page 349 Monday, May 28, 2001 10:11 AM