Specifications

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 4 Connecting with Direct Dial
Niagara Considerations
4–6
• The pass through management feature (which allows you to manage Niagara
hosts on the same LAN once you are dialed into a Niagara host) is not available
on the JACE-4/5s. It is a function of Windows RAS.
• Many IT departments prohibit setting up dial-up on hosts attached to their
network. This is considered by many departments to be a network security
violation. Therefore, it is advisable to check with them before implementing
dial-up between hosts.
Support for Interstation Links
Hosts that use dial-up to connect to other hosts do so only on demand. For instance,
a JACE in site 3 or 4 only initiates a connection to the Web Supervisor when it has
an alarm or archive to deliver. Conversely, the Web Supervisor will initiate a
connection only when it is used to maintain the hosts or answer an alarm. Therefore,
connections between hosts will connect and disconnect frequently.
Since interstation links were designed to be used across connections that
are always available, you cannot use them with direct dial.
When designing a
station you will be unable to make an interstation link to any host configured for
dial-up in the station address book.
Because interstation links are not available, if you require BUI access to remote hosts
you must license WebUI services on each remote JACE.
Connecting Multiple JACEs to One Web Supervisor
When you design a job with multiple JACEs dialing a single modem on a Web
Supervisor or JACE-NP you must keep in mind that the connection is shared. We
recommend that you:
• carefully plan your archiving strategy. For instance you could,
– use daily archiving, but stagger archive times for each JACE so they are
not attempting to send archives at the same time.
– limit the size of the logs so they do not time out when reaching the
maximum connect time for application-initiated connections.
– use trigger objects to send archives more frequently than daily so they are
not as large as a full day’s file.
• limit the number of JACEs connecting to a WS by how “busy” you expect them
to be. You can connect more lightly-loaded JACEs (ones that produce fewer
alarms and smaller or less frequent archive files) but fewer heavily-loaded
JACEs (ones that potentially alarm more and create larger or frequent archive
files).
• review your connection strategy after it has been running for a period of time.
If you find that the JACEs are not delivering information in a timely manner,
either add more modems to the Web Supervisor, or add additional Web
Supervisors.
If you find that you have too much traffic from the JACEs on a single connection you
can: