How does VRRP work with SVI's (887 router with built in LAN switch) - VLAN failover

mozmarr124 · ‎04-15-2018

Can anyone explain how VRRP works with Vlan interfaces? 2 routers, vlans and config duplicated on both routers.

How is VRRP configured and how does it operate when one (or more) vlans go down? How do they fail over to the other router?

Any help appreciated

Set up:

R1#show ip int brief
Interface IP-Address OK? Method Status Protocol
ATM0 unassigned YES NVRAM down down
ATM0.1 unassigned YES unset down down
Dialer1 10.10.91.211 YES IPCP up up
Ethernet0 unassigned YES NVRAM up up
Ethernet0.1 unassigned YES unset up up
FastEthernet0 unassigned YES unset up up
FastEthernet1 unassigned YES unset administratively down down
FastEthernet2 unassigned YES unset down down
FastEthernet3 unassigned YES unset up up <------------- interconnect to R2
Virtual-Access1 unassigned YES unset up up
Vlan1 10.163.84.62 YES NVRAM up up
Vlan2 10.163.84.126 YES NVRAM up up
Vlan3 10.163.84.142 YES NVRAM up up
Vlan5 10.210.50.126 YES NVRAM up up
Vlan6 10.163.84.254 YES NVRAM up up
Vlan8 10.163.84.158 YES NVRAM up up
Vlan9 10.163.84.190 YES NVRAM up up
Vlan99 unassigned YES NVRAM down down

pprt019740001#show vlan-switch

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa1
2 VLAN0002 active
3 VLAN0003 active Fa3
4 VLAN0004 active
5 VLAN0005 active
6 VLAN0006 active
8 VLAN0008 active
9 VLAN0009 active
1002 fddi-default act/unsup

R2#

Interface IP-Address OK? Method Status Protocol
ATM0 unassigned YES NVRAM down down
ATM0.1 unassigned YES unset down down
Cellular0 10.200.19.47 YES IPCP up up
Dialer1 unassigned YES NVRAM up up
Ethernet0 unassigned YES NVRAM administratively down down
FastEthernet0 unassigned YES unset up up
FastEthernet1 unassigned YES unset administratively down down
FastEthernet2 unassigned YES unset down down
FastEthernet3 unassigned YES unset up up <------------- interconnect to R1
Loopback0 10.201.11.47 YES NVRAM up up
Tunnel0 10.201.3.47 YES NVRAM up up
Virtual-Access1 unassigned YES unset up up
Vlan1 10.163.84.61 YES NVRAM up up
Vlan2 10.163.84.125 YES NVRAM up up
Vlan3 10.163.84.141 YES NVRAM up up
Vlan5 10.210.50.125 YES manual up up
Vlan6 10.163.84.253 YES NVRAM up up
Vlan8 10.163.84.157 YES NVRAM up up
Vlan9 10.163.84.189 YES NVRAM up up

pprt019740002#show vlan-switch

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa1
2 VLAN0002 active Fa2
3 VLAN0003 active Fa3
4 VLAN0004 active
5 VLAN0005 active
6 VLAN0006 active
8 VLAN0008 active
9 VLAN0009 active
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup

R1#sh vrrp brief
Interface Grp Pri Time Own Pre State Master addr Group addr
Vl1 6 255 3003 Y Y Master 10.163.84.62 10.163.84.62
Vl2 6 255 3003 Y Y Master 10.163.84.126 10.163.84.126
Vl3 6 255 3003 Y Y Master 10.163.84.142 10.163.84.142
Vl5 5 255 3003 Y Y Master 10.210.50.126 10.210.50.126
Vl6 6 255 3003 Y Y Master 10.163.84.254 10.163.84.254
Vl8 6 255 3003 Y Y Master 10.163.84.158 10.163.84.158
Vl9 6 255 3003 Y Y Master 10.163.84.190 10.163.84.190

R2#sh vrrp brief
Interface Grp Pri Time Own Pre State Master addr Group addr
Vl1 6 100 3609 Y Backup 10.163.84.62 10.163.84.62
Vl2 6 100 3609 Y Backup 10.163.84.126 10.163.84.126
Vl3 6 100 3609 Y Backup 10.163.84.142 10.163.84.142
Vl5 5 100 3609 Y Backup 10.210.50.126 10.210.50.126
Vl6 6 100 3609 Y Backup 10.163.84.254 10.163.84.254
Vl8 6 100 3609 Y Backup 10.163.84.158 10.163.84.158
Vl9 6 100 3609 Y Backup 10.163.84.190 10.163.84.190

Reza Sharifi · ‎04-15-2018

VRRP needs 2 IPs per vlan/subnet, one is for master and one is for backup. The routers/switches are configured the same except that the IPs that need to be different and if need to add priority and preemption and other optional commands. For the keep-alive to work correctly, there needs to be a layer-2 connection between the 2 switches or routers. This connection needs be configured as a trunk port and needs to have all vlans added. This way the routers/switches keep track of one another and if the active goes down, the backup will take over traffic forwarding.

https://networkengineering.stackexchange.com/questions/792/what-are-the-differences-between-vrrp-and-hsrp

HTH