VRRP with L3 Vlan set up

mozmarr124 · ‎12-24-2017

Hi, we have the following set up, R1 (887) to SW1 (2960) with VRRP providing redundancy to R2 and SW2.

7 vlans configured on the router each with its own IP address.

I am just trying to get in my head how this works. Can anyone comment on the config below with simple explanation of how the Group id, virtual IP, Virtual MAC and vlan ip's interact?, basically, how this works and what should happen? I can provide further output if required:

R1#

show ip int brie
(output omitted)
Vlan1 10.165.78.62 YES NVRAM up up
Vlan2 10.165.78.126 YES NVRAM up up
Vlan3 10.165.78.142 YES NVRAM up up
Vlan5 10.210.73.93 YES TFTP up up
Vlan6 10.165.78.254 YES NVRAM up up
Vlan8 10.165.78.158 YES NVRAM up up
Vlan9 10.165.78.190 YES NVRAM up up

show vrrp brie

Vlan1 - Group 6
State is Master
Virtual IP address is 10.165.78.62
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.62 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan2 - Group 6
State is Master
Virtual IP address is 10.165.78.126
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.126 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan3 - Group 6
State is Master
Virtual IP address is 10.165.78.142
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.142 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan6 - Group 6
State is Master
Virtual IP address is 10.165.78.254
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.254 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan8 - Group 6
State is Master
Virtual IP address is 10.165.78.158
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.158 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan9 - Group 6
State is Master
Virtual IP address is 10.165.78.190
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.165.78.190 (local), priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

Vlan5 - Group 5
State is Backup
Virtual IP address is 10.210.73.94
Virtual MAC address is 0000.5e00.0105
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.210.73.94, priority is 255
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 3.269 sec)

R2#

show ip int brie
(output omitted)

Vlan1 10.165.78.61 YES NVRAM up up
Vlan2 10.165.78.125 YES NVRAM up up
Vlan3 10.165.78.141 YES NVRAM up up
Vlan5 10.210.73.94 YES TFTP up up
Vlan6 10.165.78.253 YES NVRAM up up
Vlan8 10.165.78.157 YES NVRAM up up
Vlan9 10.165.78.189 YES NVRAM up up

Vlan1 - Group 6
State is Backup
Virtual IP address is 10.165.78.62 <-------- R1's Vlan 1 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.62, priority is 255 <---- R1's Vlan 1 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 2.733 sec)

Vlan2 - Group 6
State is Backup
Virtual IP address is 10.165.78.126 <------ R1's Vlan 2 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.126, priority is 255 <---- R1's Vlan 2 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 2.921 sec)

Vlan3 - Group 6
State is Backup
Virtual IP address is 10.165.78.142 <---R1's Vlan 3 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.142, priority is 255 <---R1's Vlan 3 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 2.893 sec)

Vlan6 - Group 6
State is Backup
Virtual IP address is 10.165.78.254 <---R1's Vlan 6 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.254, priority is 255 <---R1's Vlan 6 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 2.749 sec)

Vlan8 - Group 6
State is Backup
Virtual IP address is 10.165.78.158 <---R1's Vlan 8 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.158, priority is 255 <---R1's Vlan 8 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 3.285 sec)

Vlan9 - Group 6
State is Backup
Virtual IP address is 10.165.78.190 <---R1's Vlan 9 ip address
Virtual MAC address is 0000.5e00.0106
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 100
Master Router is 10.165.78.190, priority is 255 <---R1's Vlan 9 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.609 sec (expires in 2.701 sec)

Vlan5 - Group 5
State is Master
Virtual IP address is 10.210.73.94 <---R2's Vlan 5 ip address
Virtual MAC address is 0000.5e00.0105
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 255
Master Router is 10.210.73.94 (local), priority is 255 <---R2's Vlan 5 ip address
Master Advertisement interval is 1.000 sec
Master Down interval is 3.003 sec

SW1 ip default-gateway 10.165.78.126 (R1 Vlan 2 address)

SW2 ip default-gateway 10.165.78.126 (R1 Vlan 2 address)

R1 has the higher ip addresses so is the Master (?) (R1 vlan 1 ip is - 10.165.78.62, R2 vlan 1 ip is 10.165.78.61)

Julio E. Moisa · ‎12-25-2017

Hi,

I suggest use different group ID for each vlan, the reason is because the groud ID is used to create the virtual mac address, as you can see it is added to the last 2 values, so you could have problem with the arp/layer 2 communication.

Hope it is useful

:-)

>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

Georg Pauwen · ‎12-25-2017

Hello,

--> I am just trying to get in my head how this works. Can anyone comment on the config below with simple explanation of how the Group id, virtual IP, Virtual MAC and vlan ip's interact?, basically, how this works and what should happen? I can provide further output if required <--

1. Group ID: this is an arbitrary value chosen by you to identify the group that your VRRP routers (those that belong to the same subnet/cluster, or VLAN in your case) are in.

2. Virtual MAC: the virtual MAC address is the same for all VRRP routers except for the last byte of the address. This is just how IANA has defined VRRP in RFC 5798. A virtual router uses 00-00-5E-00-01-XX as MAC address. The last byte of the address (XX) is the Virtual Router IDentifier (VRID), which is different for each virtual router in the network. As Julio stated, it is identical to the VRRP group ID that you have configured (on a side note, you can define 255 VRRP groups).

3. Virtual IP: this is the IP address VRRP routers in the same cluster share to create redundancy. It is very similar to the HSRP standby address.

4. VLAN IP: on the VRRP Master, the Virtual IP address and the physical VLAN IP address are identical. On the backup, it is not...

Does that make sense ? I agree with Julio about (not) using the same group number in different clusters. I would also use a group ID that corresponds to the VLAN...