3com S7906E 설치 설명서

 

1-6 

z 

Auth Type: Authentication type. 0 means no authentication, 1 means simple text authentication, 

and 2 means MD5 authentication. VRRPv3 does not support MD5 authentication. 

z 

Adver Int: Interval for sending advertisement packets. For VRRPv2, the interval is in seconds and 

defaults to 1; for VRRPv3, the interval is in centiseconds and defaults to 100. 

z 

Checksum: 16-bit checksum for validating the data in VRRP packets. 

z 

IP Address/IPv6 Address: Virtual IPv4 or IPv6 address entry of the VRRP group. The Count IP 

Addrs or Count IPv6 Addrs field defines the number of the virtual IP v4 or IPv6 addresses. 

z 

Authentication Data: Authentication key. Currently, this field is used only for simple authentication 

and is 0 for any other authentication modes. 

z 

With VRRP enabled, the routers decide their respective roles in the VRRP group by priority and IP 

address. The router with the highest priority becomes the master, and the others are the backups; 

if the priority is the same, the router with a higher IP address becomes the master. The master 

sends VRRP advertisements periodically to notify the backups that it is working properly, and each 

of the backups starts a timer to wait for advertisements from the master. 

z 

In preemptive mode, when a backup receives a VRRP advertisement, it compares the priority in 

the packet with that of its own. If the priority of the backup is higher, the backup becomes the 

master; otherwise, it remains a backup. 

z 

In non-preemptive mode, the router in the VRRP group remains as a master or backup as long as 

the master does not fail. The backup does not become the master even if the backup is configured 

with a higher priority. 

z 

If the timer of a backup expires but the backup still does not receive any VRRP advertisement, it 

considers that the master fails. In this case, the backup considers itself as the master and sends 

VRRP advertisements to start a new master election. 

The interface tracking function expands the backup functionality of VRRP. It provides backup not only 

when the interface to which a VRRP group is assigned fails but also when other interfaces (such as 

uplink interfaces) on the router become unavailable.  

If the uplink interface of a router in a VRRP group fails, normally the VRRP group cannot be aware of the 

uplink failure. If the router is the master of the VRRP group, hosts on the LAN are not able to access the 

external network because of the uplink failure. You can solve the problem through the function of 

tracking a specified interface. In this case, it is the uplink interface. After you configure to monitor the 

uplink interface, when the uplink interface is down or removed, the priority of the master is automatically 

decreased by a specified value and a higher priority router in the VRRP group becomes the master. 

By monitoring a Track object, you can: 

z 

Monitor an uplink and modify the priority of the router according to the state of the uplink. If there is 

a fault on the uplink, hosts in the LAN cannot access the external network through the router. In this 

case, the state of the monitored Track object is negative and the priority of the router decreases by 

a specified value. After that, a higher priority router in the VRRP group becomes the master to 

maintain the proper communication between the hosts in the LAN and the external network.