07-02-2012 09:10 PM - edited 03-07-2019 07:34 AM
Hi Everyone,
I have set up vrrp between 2 routers for testing.
R1 has this config
2691Router#sh vrrp
FastEthernet1/1 - Group 20
State is Backup
Virtual IP address is 192.168.7.3
Virtual MAC address is 0000.5e00.0114
Advertisement interval is 1.000 sec
Preemption enabled, delay min 60 secs
Priority is 100
Master Router is 192.168.7.2, priority is 100
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 3.369 sec)
2691Router# sh run int fa1/1
Building configuration...
Current configuration : 256 bytes
!
interface FastEthernet1/1
ip address 192.168.7.1 255.255.255.0
duplex auto
speed auto
vrrp 20 ip 192.168.7.3
vrrp 20 preempt delay minimum 60
end
***********************************************************************************************************************
R2 is master with config
R2# sh vrrp
Ethernet1/1 - Group 20
State is Master
Virtual IP address is 192.168.7.3
Virtual MAC address is 0000.5e00.0114
Advertisement interval is 1.000 sec
Preemption enabled, delay min 60 secs
Priority is 100
Master Router is 192.168.7.2 (local), priority is 100
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec
R2# sh run int eth
R2# sh run int ethernet 1/1
Building configuration...
Current configuration : 138 bytes
!
interface Ethernet1/1
ip address 192.168.7.2 255.255.255.0
half-duplex
vrrp 20 ip 192.168.7.3
vrrp 20 preempt delay minimum 60
end
Question
Right now 1 is master and other is backup .
Need to confirm if this is correct behaviour or not??
As R2 is master even though priority is 100 on both routers so R2 became master as it has higher IP address 192.168.7.2??????????????
***********************************************************************************************************
Question
On VRRP it says when you config timer on master then backup router also follows those hello timers.
But when i config the advertise timer on master then both routers R1 and R2 becomes master and they show different timers .Need to know why this happens????????
Thanks
Mahesh
Solved! Go to Solution.
07-03-2012 03:59 AM
Mahesh,
The virtual address in vrrp can be assigned as the physical address of a real interface. In other words, if you have 192.168.7.1 as in R1, then you can assign 192.168.7.1 as the vIP unlike with HSRP where it has to be different. When vrrp is assigned a virtual address that's equal to the real address, that router becomes the master. If the router were to go down, preemption is automatically enabled by default in vrrp and causes the router with the next higher priority to take over. The problem that I think you're seeing is that there's no real ip of 192.168.7.3 being used. In that case, neither of these are really being seen as the master of the group. So because of this, since both priorities are the same, the next check is going to be the highest ip address of the group will become the master. If you want to change this behavior, you can set the priority of the one that you want as the primary to something higher than 100 and it will take over as master after your configured time of 60 seconds.
The timers between the routers in the group need to match. The master is the router that controls the timers, so when you change the timer on the master you can learn the timers on the backup or set the timer to the same interval as the other router. The default is 1 second for advertisment. From what I see, if you change the backups timer, it becomes master. Now with 2 masters, you can't change the other (original master) timer to learn from the original master because it seems that the priority and highest address still comes into play. With the original master, you'd have to send the different timer or change your priority to prefer the other router as master before sending the timer from it. On the other router (whichever backup you want) you would need to either learn (vrrp
HTH,
John
07-03-2012 03:39 AM
Hi Mahesh,
Can you share the physical setup first...
HTH,
Sukanya
07-03-2012 03:59 AM
Mahesh,
The virtual address in vrrp can be assigned as the physical address of a real interface. In other words, if you have 192.168.7.1 as in R1, then you can assign 192.168.7.1 as the vIP unlike with HSRP where it has to be different. When vrrp is assigned a virtual address that's equal to the real address, that router becomes the master. If the router were to go down, preemption is automatically enabled by default in vrrp and causes the router with the next higher priority to take over. The problem that I think you're seeing is that there's no real ip of 192.168.7.3 being used. In that case, neither of these are really being seen as the master of the group. So because of this, since both priorities are the same, the next check is going to be the highest ip address of the group will become the master. If you want to change this behavior, you can set the priority of the one that you want as the primary to something higher than 100 and it will take over as master after your configured time of 60 seconds.
The timers between the routers in the group need to match. The master is the router that controls the timers, so when you change the timer on the master you can learn the timers on the backup or set the timer to the same interval as the other router. The default is 1 second for advertisment. From what I see, if you change the backups timer, it becomes master. Now with 2 masters, you can't change the other (original master) timer to learn from the original master because it seems that the priority and highest address still comes into play. With the original master, you'd have to send the different timer or change your priority to prefer the other router as master before sending the timer from it. On the other router (whichever backup you want) you would need to either learn (vrrp
HTH,
John
07-04-2012 11:25 AM
Hi John,
Thanks for detailed explanation.
Issue is fixed now.
In VRRP hello timers has to be matched to become master and backup.
When i config the timer on master then both became masters as they had different hello times.
So under other router i config the hello timer to learn from master.
Now VRRP is working fine 1 as MAster and other as Backup.
MAny thanks again for detailed explanation
Regards
MAhesh
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