Schneider Electric 840 USE 106 0 manual Network Effects of Hot Standby Solution, Browsers

Ethernet Hot Standby So ution

Network Effects of Hot Standby Solution

Overview	The Hot Standby solution is a powerful feature of NOEs, a feature that increases the
	reliability of your installation. Hot Standby uses a network, and using the Hot
	Standby feature over a network can affect the behavior of

Browsers

Remote and Local clients

I/O Scanning service

lGlobal Data service FTP/TFTP server

The following are factors you may encounter while using the Hot Standby solution.

Browsers

Note: In Hot Standby configuration the NOE’s I/O scanner is enabled.

If a browser requests a page and during the process of downloading that page an IP Address swap occurs, the browser will either hang or time out. Click the Refresh or Reload button.

Remote Clients Hot Standby swaps affect remote clients.

An NOE will reset under the following conditions:

Remote Connection Request during Hot Standby Swap

If a remote client establishes a TCP/IP connection during a Hot Standby swap,

lthe server closes the connection using a TCP/IP reset.

Hot Standby Swap during Remote Connection Request

If a remote client makes a connection request and a Hot Standby swap occurs during the connection request, the sever rejects the TCP/IP connection by

lsending a reset.

Outstanding Requests

If there is an outstanding request, the NOE will not respond to the request, but the NOE will reset the connection.

The NOE will do a Modbus logout if any connection has logged in.

Local Clients During a swap, the NOE will reset all client connections using a TCP/IP reset.

174 840 USE 106 00 January 2003