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Redundancy

Configuring Etherchannels, HSRP and VRRP on a Cisco device.

Etherchannel​

Channel group modes​

  • on: activate Etherchannel if other is on (without protocol)

PAgP​

  • desirable: activate Etherchannel if other is desirable/auto
  • auto: activate Etherchannel if other is desirable

LACP​

  • active: activate Etherchannel if other is active/passive
  • passive: activate Etherchannel if other is active

Configuration​

interface range fa0/1 - 2
  channel-group 1 mode active
  no shutdown

interface port-channel 1
  no shutdown
  switchport mode trunk

  ! may not work on Cisco Packet Tracer together with port-channel
  switchport trunk allowed vlan 10,20

Evaluation​

#
show interfaces port-channel 1
show interfaces f0/1 etherchannel
show etherchannel summary
show etherchannel port-channel

HSRP​

sw-1-conf#
int vlan1
  ip address 10.0.0.2 255.255.0.0
  standby 1 preempt
  standby 1 priority 105
  standby 1 ip 10.0.0.1
  ! lowers the priority by 10, so 95 (default is 100) if gi1/1/1 goes down
  standby 1 track gi1/1/1
sw-2-conf#
int vlan1
  ip address 10.0.0.3 255.255.0.0
  standby 1 preempt
  standby 1 ip 10.0.0.1