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Configuring VRRP

The Virtual Router Redundancy Protocol (VRRP) provides redundant gateway service for switches and other IP end stations. In the Viptela software, you configure VRRP on an interface, and typically on a subinterface, within a VPN.

For a VRRP interface to operate, its physical interface must be configured in VPN 0:

vEdge(config-vpn-0)# interface ge-slot/port
vEdge(config-interface-ge)# no shutdown

For each VRRP interface (or subinterface), you assign an IP address and you place that interface in a VRRP group.

vEdge(config-vpn)# interface ge-slot/port.subinterface
vEdge(config-interface-ge)# ip address prefix/length
vEdge(config-interface-ge)# vrrp group-number

The group number identifies the virtual router. In a typical VRRP topology, two physical routers are configured to act as a single virtual router, so you configure the same group number on interfaces on both these routers.

For each virtual router ID, you must configure an IP address:

vEdge(config-vrrp)# ipv4 ip-address

Within each VRRP group, the vEdge router with the higher priority value is elected as master. By default, each virtual router IP address has a default master election priority of 100, so the router with the higher IP address is elected master. You can modify the priority value, setting it to a value from 1 through 254:

vEdge(config-vrrp)# priority number

The VRRP master periodically sends advertisement messages, indicating that it is still operating. If backup routers miss three consecutive VRRP advertisements, they assume that the master is down and elect a new master. By default, these messages are sent every second. You can change the VRRP advertisement time to be a value from 1 through 3600 seconds:

vEdge(config-vrrp)# timer seconds

By default, VRRP uses of the state of the interface on which it is running to determine which vEdge router is the master virtual router. This interface is on the service (LAN) side of the vEdge router. When the interface for the master goes down, a new VRRP master virtual router is elected based on the VRRP priority value. Because VRRP runs on a LAN interface, if a vEdge router loses all its WAN control connections, the LAN interface still indicates that it is up even though the router is functionally unable to participate in VRRP. To take WAN side connectivity into account for VRRP, you can configure one of the following:

  • Track the Overlay Management Protocol (OMP) session running on the WAN connection when determining the VRRP master virtual router:
vEdge(config-vrrp)# track-omp

If all OMP sessions are lost on the master VRRP router, VRRP elects a new default gateway from among all the gateways that have one or more active OMP sessions even if the gateway chosen has a lower VRRP priority than the current master. With this option, VRRP failover occurs once the OMP state changes from up to down, which occurs when the OMP hold timer expires. (The default OMP hold timer interval is 60 seconds.) Until the hold timer expires and a new VRRP master is elected, all overlay traffic is dropped. When the OMP session recovers, the local VRRP interface claims itself as master even before it learns and installs OMP routes from the vSmart controllers. Until the routers are learned, traffic is also dropped.

  • Track both the OMP session and a list of remote prefixes. list-name is the name of a prefix list configured with the policy lists prefix-list command on the vEdge router:
vEdge(config-vrrp)# track-prefix-list list-name

If all OMP sessions are lost, VRRP failover occurs as described for the track-omp option. In addition, if reachability to all the prefixes in the list is lost, VRRP failover occurs immediately, without waiting for the OMP hold timer to expire, thus minimizing the amount of overlay traffic is dropped while the vEdge routers determine the VRRP master.

As discussed above, the IEEE 802.1Q protocol adds 4 bytes to each packet's length. Hence, for packets to be transmitted, either increase the MTU size on the physical interface in VPN 0 (the default MTU is 1500 bytes) or decrease the MTU size on the VRRP interface. See the example configuration output below.

Here is an example of configuring VRRP on redundant physical interfaces. For subinterface 2, vEdge1 is configured to act as the master, and for subinterface 3, vEdge2 acts as the master.

vEdge1# show running-config vpn 1 
vpn 1
 interface ge0/6.2
  ip address 10.2.2.3/24
  mtu      1496
  no shutdown
  vrrp 2
   ipv4 10.2.2.1
   track-prefix-list vrrp-prefix-list1
  !
 !
 interface ge0/6.3
  ip address 10.2.3.5/24
  mtu      1496
  shutdown
  vrrp 3
   ipv4 10.2.3.11
   track-prefix-list vrrp-prefix-list1
  !
 !
!

vEdge2# show running-config vpn 1 
vpn 1
 interface ge0/1.2
  ip address 10.2.2.4/24
  mtu      1496
  no shutdown
  vrrp 2
   ipv4 10.2.2.2
   track-prefix-list vrrp-prefix-list2
  !
 !
 interface ge0/1.3
  ip address 10.2.3.6/24
  mtu      1496
  no shutdown
  vrrp 3
   ipv4 10.2.3.12
   track-prefix-list vrrp-prefix-list2
  !
 !
!

vEdge1# show interface vpn 1 
 
                             IF      IF                                                              TCP                                   
                             ADMIN   OPER    ENCAP  PORT                              SPEED          MSS                 RX       TX       
VPN  INTERFACE  IP ADDRESS   STATUS  STATUS  TYPE   TYPE     MTU   HWADDR             MBPS   DUPLEX  ADJUST  UPTIME      PACKETS  PACKETS  
-------------------------------------------------------------------------------------------------------------------------------------------
1    ge0/6.2    10.2.2.3/24  Up      Up      vlan   service  1496  00:0c:29:ab:b7:94  10     full    0       0:00:05:52  0        357      
1    ge0/6.3    10.2.3.5/24  Down    Down    vlan   service  1496  00:0c:29:ab:b7:94  -      -       0       -           0        0 

vEdge1# show vrrp interfaces       

                                                                                           MASTER                             TRACK   PREFIX  
              GROUP  VIRTUAL                                 VRRP    OMP    ADVERTISEMENT  DOWN                               PREFIX  LIST    
VPN  IF NAME  ID     IP         VIRTUAL MAC        PRIORITY  STATE   STATE  TIMER          TIMER   LAST STATE CHANGE TIME     LIST    STATE   
----------------------------------------------------------------------------------------------------------------------------------------------
1    ge0/6.2  2      10.2.2.1   00:0c:29:ab:b7:94  100       master  down   1              3       2015-05-01T20:09:37+00:00  -       -       
     ge0/6.3  3      10.2.3.11  00:00:00:00:00:00  100       init    down   1              3       0000-00-00T00:00:00+00:00  -       -     

In the following example, Router-1 is the VRRP master, because it has a higher priority value than Router 2:

Router-1# show running-config vpn 1
vpn 1
!
 interface ge0/1.15
  ip address 10.10.1.2/24
  mtu         1496
  no shutdown
  vrrp 15
   priority  110
   track-omp
   ipv4 10.20.23.1
  !
 !
!

Router-1# show vrrp vpn 1
                                                                                                MASTER                             TRACK   PREFIX  
               GROUP                                              VRRP    OMP    ADVERTISEMENT  DOWN                               PREFIX  LIST    
VPN  IF NAME   ID     VIRTUAL IP     VIRTUAL MAC        PRIORITY  STATE   STATE  TIMER          TIMER   LAST STATE CHANGE TIME     LIST    STATE   
---------------------------------------------------------------------------------------------------------------------------------------------------
1    ge0/1.1   1      10.20.22.1     00:0c:bd:08:79:a4  100       backup  up     1              3       2016-01-13T03:10:55+00:00  -       -       
     ge0/1.5   5      10.20.22.193   00:0c:bd:08:79:a4  100       backup  up     1              3       2016-01-13T03:10:55+00:00  -       -       
     ge0/1.10  10     10.20.22.225   00:0c:bd:08:79:a4  100       backup  up     1              3       2016-01-13T03:10:55+00:00  -       -       
     ge0/1.15  15     10.20.23.1     00:0c:bd:08:79:a4  110       master  up     1              3       2016-01-13T03:10:56+00:00  -       -       
     ge0/1.20  20     10.20.24.1     00:0c:bd:08:79:a4  100       backup  up     1              3       2016-01-13T03:10:56+00:00  -       -       
     ge0/1.25  25     10.20.25.1     00:0c:bd:08:79:a4  110       master  up     1              3       2016-01-13T03:10:56+00:00  -       -       
     ge0/1.30  30     10.20.25.129   00:0c:bd:08:79:a4  100       backup  up     1              3       2016-01-13T03:10:56+00:00  -       -   


Router-1# show vrrp vpn 1 interfaces ge0/1.15 groups 15

                                                                               MASTER                             TRACK   PREFIX  
GROUP                                            VRRP    OMP    ADVERTISEMENT  DOWN                               PREFIX  LIST    
ID     VIRTUAL IP   VIRTUAL MAC        PRIORITY  STATE   STATE  TIMER          TIMER   LAST STATE CHANGE TIME     LIST    STATE   
----------------------------------------------------------------------------------------------------------------------------------
1      10.20.33.1  00:0c:bd:08:79:a4  110       master  up     1              3       2016-01-13T03:10:56+00:00  -       -       

Router-2# show running-config vpn 1
vpn 1
!
 interface ge0/1.15
  ip address 10.10.1.3/24
  mtu         1496
  no shutdown
  vrrp 15
   track-omp
   ipv4 10.20.23.1
  !
 !
!

Router-2# show vrrp vpn 1 interfaces groups

                                                                                           MASTER                             TRACK   PREFIX  
          GROUP                                              VRRP    OMP    ADVERTISEMENT  DOWN                               PREFIX  LIST    
IF NAME   ID     VIRTUAL IP     VIRTUAL MAC        PRIORITY  STATE   STATE  TIMER          TIMER   LAST STATE CHANGE TIME     LIST    STATE   
----------------------------------------------------------------------------------------------------------------------------------------------
ge0/1.1   1      10.20.32.1     00:0c:bd:08:2b:a5  110       master  up     1              3       2016-01-13T00:22:15+00:00  -       -       
ge0/1.5   5      10.20.32.193   00:0c:bd:08:2b:a5  110       master  up     1              3       2016-01-13T00:22:15+00:00  -       -       
ge0/1.10  10     10.20.32.225   00:0c:bd:08:2b:a5  110       master  up     1              3       2016-01-13T00:22:15+00:00  -       -       
ge0/1.15  15     10.20.33.1     00:0c:bd:08:2b:a5  100       backup  up     1              3       2016-01-13T03:10:56+00:00  -       -       
ge0/1.20  20     10.20.34.1     00:0c:bd:08:2b:a5  110       master  up     1              3       2016-01-13T00:22:16+00:00  -       -       
ge0/1.25  25     10.20.35.1     00:0c:bd:08:2b:a5  100       backup  up     1              3       2016-01-13T03:10:56+00:00  -       -       
ge0/1.30  30     10.20.35.129   00:0c:bd:08:2b:a5  100       master  up     1              3       2016-01-13T00:22:16+00:00  -       -    

Router-2# show vrrp vpn 100 interfaces groups 15

                                                                                         MASTER                             TRACK   PREFIX  
          GROUP                                            VRRP    OMP    ADVERTISEMENT  DOWN                               PREFIX  LIST    
IF NAME   ID     VIRTUAL IP   VIRTUAL MAC        PRIORITY  STATE   STATE  TIMER          TIMER   LAST STATE CHANGE TIME     LIST    STATE   
--------------------------------------------------------------------------------------------------------------------------------------------
ge0/0.15  15     10.20.33.1   00:0c:bd:08:2b:a5  100       backup  up     1              3       2016-01-13T03:10:56+00:00  -       -
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