Qtech QSW-3900-24-Т-DC [94/313] Backup s monitoring of the master state

Qtech QSW-3900-RAC [94/313] Backup s monitoring of the master state
QTECH Software Configuration Manual
7-93
7.2.3.3 Authentication Mode
VRRP provides three authentication modes:
No authentication: No authentication is performed for any VRRP packet,
without security guarantee.
Simple text authentication: You can adopt the simple text authentication
mode in a network facing possible security problems. A router sending a
VRRP packet fills an authentication key into the packet, and the router
receiving the packet compares its local authentication key with that of the
received packet. If the two authentication keys are the same, the received
VRRP packet is considered valid; otherwise, the received packet is
considered an invalid one.
MD5 authentication: You can adopt MD5 authentication in a network
facing severe security problems. The router encrypts a VRRP packet to be
sent using the authentication key and MD5 algorithm and saves the
encrypted packet in the authentication header. The router receiving the
packet uses the authentication key to decrypt the packet and checks
whether the validity of the packet.
7.2.4 Backup’s Monitoring of the Master State
In normal cases, a backup in a virtual router waits for Master_Down_Interval to become the master after the master
fails. During this time, the hosts in the LAN cannot communicate as no master can forward packets for them. To
solve the problem, VRRP provides the monitoring function for a backup to monitor the master state, making the
backup become the new master immediately after the master fails to maintain network communication.
The BFD technology is adopted for a backup to monitor the master state. With this function enabled on a backup, the
backup can automatically become the new master as soon as the master fails, with the Skew Time being reduced to
milliseconds.
7.3 Application Scenarios
7.3.1 4Master/Backup
In master/backup mode, only one router, the master, provides services. When the master fails, a new master is elected
from the original backups to take the responsibility of the master, as shown in Figure 3 .

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