Link-Track Feature

Link-track feature is used when uplink on the master (ES1-24p-1) fails and the forwarding capability gets affected. If uplink on ES1-24p-1 goes down, a trigger is generated to decrement ES1-24p-1's current priority. The election process begins again with the new decremented priority and a new master is elected. The priority should be decremented such that it is less than the priority of the backup (ES1-24p-2). Hence, the backup (ES1-24p-2) becomes the master and forwarding capability is carried by ES1-24p-2. When the uplink on the ES1-24p-1 comes back, the reverse process occurs and the ES1-24p-1 advertises with original priority and after election process ES1-24p-1 again becomes the master.

1. Configure the VLAN interface (uplink) and number of links to track.

   ES1-24p-1 SEFOS# configure terminal 
   ES1-24p-1 SEFOS(config)# track 1 interface vlan 20
   ES1-24p-1 SEFOS(config)# track 1 links 1
   ES1-24p-1 SEFOS(config)# end
   

2. Configure the VLAN interface (VRRP) to decrement the priority to 100 for IPv4 and IPv6, incase the uplink goes down.

   ES1-24p-1 SEFOS# configure terminal 
   ES1-24p-1 SEFOS(config)# router vrrp
   ES1-24p-1 SEFOS(config-vrrp)# vrrp version v3
   ES1-24p-1 SEFOS(config-vrrp)# interface vlan 100
   ES1-24p-1 SEFOS(config-vrrp-if)# vrrp 1 ipv4 track 1 decrement 100
   ES1-24p-1 SEFOS(config-vrrp-if)# vrrp 1 ipv6 track 1 decrement 100
   ES1-24p-1 SEFOS(config-vrrp-if)# end
   

3. Shutdown the uplink.

   ES1-24p-1 SEFOS# configure terminal
   ES1-24p-1 SEFOS(config)# interface vlan 20
   ES1-24p-1 SEFOS(config-if)# shutdown
   ES1-24p-1 SEFOS(config-if)# end
   

4. Verify VRRP state changes.

   ES1-24p-1 SEFOS# show vrrp
   P indicates configured to preempt
   Interface vrID Prio P State  Master Address            VRouter Address 
   --------- ---- ---- - -----  ------------------------- -------------------------
   vlan100   1    100  P Backup 192.168.100.10            192.168.100.1 
   vlan100   1    100  P Backup fe80::210:e0ff:fe2a:fd41  fe80::210:e0ff:fe2c:fd21 
    
   ES1-24p-2 SEFOS# show vrrp
   P indicates configured to preempt
   Interface vrID Prio P State  Master Address            VRouter Address 
   --------- ---- ---- - -----  ------------------------- -------------------------
   vlan100   1    150  P Master 192.168.100.10            192.168.100.1 
   vlan100   1    150  P Master fe80::210:e0ff:fe2a:fd41  fe80::210:e0ff:fe2c:fd21
   

5. Enable the uplink.

   ES1-24p-1 SEFOS# configure terminal 
   ES1-24p-1 SEFOS(config)# interface vlan 20
   ES1-24p-1 SEFOS(config-if)# no shutdown 
   ES1-24p-1 SEFOS(config-if)# end
    
   ES1-24p-1 SEFOS# show vrrp
   P indicates configured to preempt
   Interface vrID Prio P State  Master Address            VRouter Address 
   --------- ---- ---- - -----  ------------------------- -------------------------
   vlan100   1    200  P Master 192.168.100.20            192.168.100.1 
   vlan100   1    200  P Master fe80::210:e0ff:fe2c:f21   fe80::210:e0ff:fe2c:fd21 
   ES1-24p-2 SEFOS# show vrrp
   P indicates configured to preempt
   Interface vrID Prio P State  Master Address            VRouter Address 
   --------- ---- ---- - -----  ------------------------- -------------------------
   vlan100   1    150  P Backup 192.168.100.20            192.168.100.1 
   vlan100   1    150  P Backup fe80::210:e0ff:fe2c:f21   fe80::210:e0ff:fe2c:fd21