Advantech ER75s, User Manual

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ER75s
8.9 VRRP configuration
To enter the VRRP configuration select the VRRP menu item. VRRP protocol (Virtual
Router Redundancy Protocol) is a technique, by which it is possible to forward routing from
main router to backup router in the case of the main router failure. If the
Enable VRRP is
checked, then it is possible to set the following parameters.
Item Description
Virtual Server IP Address This parameter sets virtual server IP address. This address
should be the same for both routers. A connected device
sends its data via this virtual address.
Virtual Server ID Parameter Virtual Server ID distinguishes one virtual router
on the network from others. Main and backup routers must
use the same value for this parameter.
Host Priority The router, with higher priority set by the parameter Host
Priority, is the main router. According to RFC 2338 the main
router has the highest possible priority - 255. The backup
router has priority in range 1 – 254 (init value is 100). The
priority value equals 0 is not allowed.
Table 22: VRRP configuration
It is possible to set Check connection flag in the second part of the window. The currently
active router (main/backup) will send testing messages to defined
Ping IP Address
at periodic
time intervals ( Ping Interval ) with setting time of waiting for answer ( Ping Timeout ). The func-
tion check connection is used as a supplement of VRRP standard with the same final result.
If there are no answers from remote devices (
Ping IP Address
) for a defined number of probes
( Ping Probes ), then connection is switched to the other line.
Item Description
Ping IP Address Destination IP address of ping queries. Address can not be spec-
ified as domain name.
Ping Interval Time intervals between the outgoing pings.
Ping Timeout Time to wait to answer.
Ping Probes Number of failed ping requests, after which the route is considered
to be impassable.
Table 23: Check connection
Ping IP address is possible to use for example a DNS server of mobile operator as a test
message (ping) IP address.
There’s an additional way for evaluating the state of the active line. It is activated by select-
ing Enable traffic monitoring parameter. If this parameter is set and any packet different from
ping is sent to the monitored line, then any answer to this packet is expected for
Ping Timeout
.
If Ping Timeout expires with no answer received then process of testing the active line contin-
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