Operation Manual – VRRPH3C S5500-EI Series Ethernet Switches Chapter 1 VRRP Configuration1-7z Auth Type: Authentication type. 0 means no authentication, 1 means simpleauthentication. VRRPv3 does not support MD5 authentication.z Adver Int: Interval for sending advertisement packets, in centiseconds. The defaultis 100.z Checksum: 16-bit checksum for validating the data in VRRPv3 packets.z IPv6 Address: Virtual IPv6 address entry of the standby group. The allowednumber is given by the Count IPv6 Addrs field.z Authentication Data: Authentication key. Currently, this field is used only for simpleauthentication and is 0 for any other authentication modes.1.1.5 Principles of VRRPz With VRRP enabled, the switches determine their respective roles in the standbygroup by priority. The switch with the highest priority becomes the master, whilethe others are the backups. The master sends VRRP advertisement packetsperiodically to notify the backups that it is working properly, and each of thebackups starts a timer to wait for advertisement packets from the master.z In preemption mode, when a backup receives a VRRP advertisement packet, itcompares the priority in the packet with that of its own. If its priority is higher, itbecomes the master; otherwise, it remains a backup.z In non-preemption mode, the switch in the standby group remains as a master orbackup as long as the master does not fail. The backup will no become the mastereven if the former is configured with a higher priority.z If the timer of a backup expires but the backup still does not receive any VRRPadvertisement packet, it considers that the master fails. In this case, the backupswitch considers itself as the master switch and sends VRRP advertisements tostart the election process to elect a new master switch for forwarding packets.1.1.6 VRRP Interface TrackingThe interface tracking function expands the backup functionality of VRRP. It providesbackup not only when the interface to which a standby group is assigned fails but alsowhen other interfaces on the switch become unavailable. This is achieved by trackinginterfaces. When a monitored interface goes down, the priority of the switch owning theinterface is automatically decreased by a specified value, allowing a higher priorityswitch in the standby group to become the master.1.1.7 VRRP Application (Taking IPv4-Based VRRP for Example)I. Master/backupIn master/backup mode, only one switch, the master, provides services. When themaster fails, a new master is elected from the original backups. This mode requires
