System information

CONFIGURATION
1.9. 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.
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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 12: VRRP configuration
It is possible to set Check PPP 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 function check PPP 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.
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Ping IP Address Destinations IP address ping queries. Address can not specify 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 13: Check PPP 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 selecting 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 continues the same way like in the case of standard testing process after first
test message answer drops out.
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