User`s guide
Configuring VRRP
9-2 Configuring VRRP
Configuring VRRP
ThissectionpresentsthefollowingsampleVRRPconfigurations:
•AbasicVRRPconfigurationwithonevirtualrouter(page9‐3)
•AsymmetricalVRRPconfigurationwithtwovirtualrouters(page9‐5)
•Amulti‐backupVRRPconfigurationwiththreevirtualrouters(page9‐8)
master The router assigned to forward traffic designated for the virtual router. The master
sends an advertisement to all other VRRP routers declaring its status and assumes
responsibility for forwarding packets associated with its VRID.
backup The router that takes over and begins forwarding traffic for the virtual router if the
master router becomes unavailable. When more than one backup is configured for a
VRID, then the priority value (as described below) will determine whether a router will
act as a primary or secondary backup.
virtual router Designates an IP address and VRID associated with a default route to use if the
master router becomes unavailable. As long as one of the routers in a VRRP
configuration is up, the IP addresses assigned to the virtual router are always
available, and the end hosts can send packets to these IP addresses without
interruption.
owner A value used in setting a VRRP address which indicates if a router owns an IP
address. A value or 1 indicates the router owns the address and is, therefore, the
master router for that interface. A value of 0 indicates the router does not own the
address and is a backup for the interface.
priority Specifies a VRRP priority value to associate with a VRID. Valid values are from 1 to
254, with the highest value setting the highest priority. If the virtual router IP address
is not owned by any of the VRRP routers, then the routers compare their priorities
and the higher priority owner becomes the master. If priority values are the same,
then the VRRP router with the higher IP address is selected master.
Note: Priority value of 255 is reserved for the VRRP router that owns the IP
address associated with the virtual router. Priority 0 is reserved for signaling
that the master has stopped working and the backup router must transition
to master state.
Table 9-1 VRRP Terms and Definitions (continued)
Term Definition
Important Notice
The configuration examples provided in this section assume that IP routing has been enabled on all routing
modules as described in Chapter 7, Configuring IP. Examples use VLAN 1 as the configured routing
interface. Depending on your configuration, your router and VLAN IDs may be different.
Notes: In some instances, a heavy load on a VRRP master may delay VRRP packet transmission
and cause the backup router to assume the role of master.
Each Matrix DFE Series routing module or N-SA device supports up to 64 VRRP sessions. A
session is defined as one virtual router running on one interface. Running a single virtual router on
four interfaces is considered four sessions of VRRP, as is running four virtual routers on a single
interface.
Do not use an IP address for VRRP that is already configured for load-balancing.