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Re: VRRP with Multiple Vlan's and Mutiple Subnets

 
SantoshN
Occasional Advisor

VRRP with Multiple Vlan's and Mutiple Subnets

Hi,

I Have 2 numbers of HP 5412 R switches and configuring VRRP & MSTP. Also i have multiple Vlans and Multiple IP subnets.

My query is we should configure multiple virtual IP address for each VLAN or for all VLAN's and all subnets i can use  single virtual IP.

I configure as below..

vlan 34

   name "VLAN34"

   tagged A23-A24

   ip address 172.25.34.1 255.255.255.0

   ip helper-address 172.25.33.5

   vrrp vrid 34

      virtual-ip-address 172.25.34.3

      priority 254

      enable

      exit

   exit

vlan 35

   name "VLAN35"

   tagged A23-A24

   ip address 172.25.35.1 255.255.255.0

   ip helper-address 172.25.33.5

   vrrp vrid 35

      virtual-ip-address 172.25.35.3

      enable

      exit

 

But I want to use only one Virtual IP address for all VLANs. Is it possible or not. Can any one guide me.

 

 

4 REPLIES 4
Vince-Whirlwind
Honored Contributor

Re: VRRP with Multiple Vlan's and Mutiple Subnets

The VRRP virtual address is the router address for its subnet.
Each subnet needs a router address within that subnet.
So 10.10.34.3 is the router address for the 10.10.34.0 subnet, 10.10.35.3 is the router address for the 10.10.35.0 subnet, etc...

You don't need separate VRIDs for each subnet - in fact as the number of available VRIDs is much smaller than the number of possible VLANs, you should probably match VRIDs to MSTP instances instead of matching them to VLAN IDs.

Just as an aside, I personally much prefer to use, eg, 10.10.34.1 as the virtual address, with 10.10.34.2 on the VRRP master and 10.10.34.3 on the VRRP backup.
That way, you can remember that 10.10.x.1 is the router address for every 10.10.x.0/24 subnet.

SantoshN
Occasional Advisor

Re: VRRP with Multiple Vlan's and Mutiple Subnets

Thank-you. Will do the same today.
SantoshN
Occasional Advisor

Re: VRRP with Multiple Vlan's and Mutiple Subnets

Hi,

I have configure MSTP in my switch 1 & switch2  is  below config is correct.

On Switch 1:

spanning-tree
spanning-tree Trk1 priority 4
spanning-tree config-name "vrrp"
spanning-tree config-revision 1
spanning-tree instance 1 vlan 32-34
spanning-tree instance 1 priority 4
spanning-tree instance 1 Trk1 priority 4
spanning-tree instance 2 vlan 35-40
spanning-tree instance 2 priority 4
spanning-tree instance 2 Trk1 priority 4
spanning-tree priority 4

 

On Switch 2:

spanning-tree
spanning-tree Trk1 priority 3
spanning-tree config-name "vrrp"
spanning-tree config-revision 1
spanning-tree instance 1 vlan 32-34
spanning-tree instance 1 priority 3
spanning-tree instance 1 Trk1 priority 3
spanning-tree instance 2 vlan 35-40
spanning-tree instance 2 priority 3
spanning-tree instance 2 Trk1 priority 3
spanning-tree priority 3

 

 

Vince-Whirlwind
Honored Contributor

Re: VRRP with Multiple Vlan's and Mutiple Subnets

Frankly, I'm not a fan of MSTP, generally.

Splitting load across your two cores might seem like a fun thing to do, but as the whole point of redundancy is that any one of them should be fine carrying 100% of the load on its own, this begs the question of why you want to split the load in the first place, especially as it adds to the size of the configs and increases the complexity for whoever has to manage the network on a day-to-day basis.

Increased complexity = increased risk. You would want the increased complexity to deliver some tangible benefits to justify introducing it.

One thing I used to do is I would periodically change the STP priority and VRRP priority on my "master core" to force the "backup core" to take over. Then monitor. That way I would maximise the chance of any potential failover problems occurring within a planned change window instead of maybe occurring during an unplanned event, which could spoil a day at the beach for me...