3com 5500-ei pwr Instruccion De Instalación

 

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When the VLAN interface of the master goes down, if you want the specified backup to become the 

master, you can use the interface tracking function. With this function enabled for the VRRP group: 

z 

If the tracked VLAN interface of the master goes down, the priority of the switch decreases 

automatically by a specified value. 

z 

The decrease of the master priority makes the priority of the backup tracking the interface become 

higher, and thus the backup becomes the new master. 

When a physical port of the master goes down, if you want the specified backup to become the master, 

you can use the port tracking function. With this function enabled for the VRRP group: 

z 

If the tracked physical port of the master goes down, the priority of the master decreases 

automatically by a set value. 

z 

The decrease of the master priority makes the priority of the backup tracking the port become 

higher, and thus the backup becomes the new master. 

z 

With VRRP enabled, the switches determine their respective roles in a VRRP group by priority. The 

switch with the highest priority acts as the master, which will forward packets to outside networks, 

and the switches with lower priorities act as backups. The master sends VRRP advertisements 

periodically to notify that it is operating normally. 

z 

When a backup receives a VRRP advertisement, it compares its own priority with that in the 

advertisement. If its priority is lower, it remains as a backup. Otherwise, it becomes the master. 

z 

A backup starts the advertisement interval timer after it receives the advertisement to wait for the 

next one from the master. If the backup does not receive VRRP advertisements from the master 

after the timer expires, it considers that the master fails and starts the election process to elect a 

new master for forwarding packets. 

If a VRRP group exists on a network, the master sends gratuitous ARP packets periodically to hosts on 

the network, which then update their local ARP tables, ensuring that no device on this network uses the 

same IP address with the VRRP virtual router. 

As you can create mappings between the IP address and MAC address of the VRRP virtual router, 

there are two cases: 

z 

If the IP address of the virtual router corresponds to a virtual MAC address, the source MAC 

address in the gratuitous ARP packet will be the virtual MAC address. 

z 

If the IP address of the virtual router corresponds to an actual MAC address, the source MAC 

address in the gratuitous ARP packet will be the VLAN interface’s MAC address of the master in 

the VRRP group. 

 

For more information about ARP, refer to ARP Operation in this manual.