Sunday, October 25, 2015

High Availability Protcol - HSRP , VRRP and GLBP










R1
interface FastEthernet0/0
 ip address 10.0.0.254 255.255.255.0
  standby 1 ip 10.0.0.1
end
R2
interface FastEthernet0/0
 ip address 10.0.0.253 255.255.255.0
 standby 1 ip 10.0.0.1
R3
interface FastEthernet0/0
 ip address 10.0.0.252 255.255.255.0
 standby 1 ip 10.0.0.1
end

********************************LOGS********************

R1
R1#sh standby
FastEthernet0/0 - Group 1
  State is Active
    2 state changes, last state change 00:16:20
  Virtual IP address is 10.0.0.1
  Active virtual MAC address is 0000.0c07.ac01
    Local virtual MAC address is 0000.0c07.ac01 (v1 default)
  Hello time 3 sec, hold time 10 sec
    Next hello sent in 2.904 secs
  Preemption disabled
  Active router is local
  Standby router is 10.0.0.253, priority 100 (expires in 7.884 sec)
  Priority 100 (default 100)
  Group name is "hsrp-Fa0/0-1" (default)
R1#

R2
FastEthernet0/0 - Group 1
  State is Standby
    4 state changes, last state change 00:15:00
  Virtual IP address is 10.0.0.1
  Active virtual MAC address is 0000.0c07.ac01
    Local virtual MAC address is 0000.0c07.ac01 (v1 default)
  Hello time 3 sec, hold time 10 sec
    Next hello sent in 2.492 secs
  Preemption disabled
  Active router is 10.0.0.254, priority 100 (expires in 8.540 sec)
  Standby router is local
  Priority 100 (default 100)
  Group name is "hsrp-Fa0/0-1" (default)
R2#

R3


R3#sh standby
FastEthernet0/0 - Group 1
  State is Listen
    3 state changes, last state change 00:17:10
  Virtual IP address is 10.0.0.1
  Active virtual MAC address is 0000.0c07.ac01
    Local virtual MAC address is 0000.0c07.ac01 (v1 default)
  Hello time 3 sec, hold time 10 sec
  Preemption disabled
  Active router is 10.0.0.254, priority 100 (expires in 8.824 sec)
  Standby router is 10.0.0.253, priority 100 (expires in 9.792 sec)
  Priority 100 (default 100)
  Group name is "hsrp-Fa0/0-1" (default)

Case 1 - interface is down 

R2(config)#int fa0/0
R2(config-if)#shut
R2#sh standby
FastEthernet0/0 - Group 1
  State is Init (interface down)
R3

R3#sh standby
FastEthernet0/0 - Group 1
  State is Standby   >>>> This is now in standby mode 

Case 2 Active router is down

R1
int f0/0
shut

R3#
*Mar  1 00:37:26.051: %HSRP-5-STATECHANGE: FastEthernet0/0 Grp 1 state Standby -> Active
R3#

R3#sh standby
FastEthernet0/0 - Group 1
  State is Active
    5 state changes, last state change 00:03:03
  Virtual IP address is 10.0.0.1
  Active virtual MAC address is 0000.0c07.ac01
    Local virtual MAC address is 0000.0c07.ac01 (v1 default)


10.0.0.1 icmp_seq=259 ttl=255 time=46.800 ms
10.0.0.1 icmp_seq=260 ttl=255 time=46.800 ms
10.0.0.1 icmp_seq=261 timeout       With a packet drop traffic switched over
10.0.0.1 icmp_seq=262 ttl=255 time=62.400 ms
10.0.0.1 icmp_seq=263 ttl=255 time=62.400 ms

*****************
Sh arp
***************
VPCS[1]> arp

00:00:0c:07:ac:01  10.0.0.1 expires in 111 seconds

R3#sh ip arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.0.0.1                -   0000.0c07.ac01  ARPA   FastEthernet0/0
Internet  10.0.0.10               4   0050.7966.6800  ARPA   FastEthernet0/0
Internet  10.0.0.252              -   c202.1850.0000  ARPA   FastEthernet0/0


If a router ,  which was active earlier , is up again, there will be no change in active gateway this router will be in standby mode.

R1(config)#int fa0/0
R1(config-if)#no shut
R1(config-if)#^Z
R#
R1#
*Mar  1 00:44:20.503: %HSRP-5-STATECHANGE: FastEthernet0/0 Grp 1 state Speak -> Standby
R1#

to make this  router again an active gateway preempt is used.


R1(config)#int fa0/0
R1(config-if)#standby 1 preempt delay minimum 3
R1(config-if)#standby 1 priority 200

R1#
*Mar  1 00:50:02.187: %SYS-5-CONFIG_I: Configured from console by console
R1#
*Mar  1 00:50:05.251: %HSRP-5-STATECHANGE: FastEthernet0/0 Grp 1 state Standby -> Active
R1#sh

in 3 second this router is again ACTIVE.


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