Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 434)

416 Brocade ICX 6650 Layer 3 Routing Configuration Guide
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VRRP and VRRP-E overview
NOTE
Regardless of the setting for the preempt parameter, the Owner always becomes the Master again
when it comes back online.
Track ports and track priority
The Brocade implementation of VRRP enhances the protocol by giving a VRRP router the capability
to monitor the state of the interfaces on the other end of the route path through the router. For
example, in
Figure 31 on page 413, interface e1/1/6 on Switch 1 owns the IP address to which
Host1 directs route traffic on its default gateway. The exit path for this traffic is through the
Switch 1 e1/1/2 interface.
Suppose interface e1/1/2 goes down. Even if interface e1/1/6 is still up, Host1 is cut off from
other networks. In conventional VRRP, Switch 1 would continue to be the Master router despite the
unavailability of the exit interface for the path the router is supporting. However, if you configure
interface e1/1/6 to track the state of interface e1/1/2, if e1/1/2 goes down, interface e1/1/6
responds by changing the Switch 1 VRRP priority to the value of the track priority. In the
configuration shown in
Figure 31 on page 413, the Switch 1 priority changes from 255 to 20. One
of the parameters contained in the Hello messages the Master router sends to its Backup routers is
the Master router priority. If the track port feature results in a change in the Master router priority,
the Backup routers quickly become aware of the change and initiate a negotiation to become the
Master router.
In Figure 31 on page 413, the track priority results in the Switch 1 VRRP priority becoming lower
than the Switch 2 VRRP priority. As a result, when Switch 2 learns that it now has a higher priority
than Switch 1, Switch 2 initiates negotiation to become the Master router and becomes the new
Master router, thus providing an open path for the Host1 traffic. To take advantage of the track
port feature, make sure the track priorities are always lower than the VRRP priorities. The default
track priority for the router that owns the VRID IP addresses is 2. The default track priority for
Backup routers is 1. If you change the track port priorities, make sure you assign a higher track
priority to the Owner of the IP addresses than the track priority you assign on the Backup routers.
Suppression of RIP advertisements for backed-up interfaces
The Brocade implementation also enhances VRRP by allowing you to configure the protocol to
suppress RIP advertisements for the backed-up paths from Backup routers. Normally, a VRRP
Backup router includes route information for the interface it is backing up in RIP advertisements.
As a result, other routers receive multiple paths for the interface and might sometimes
unsuccessfully use the path to the Backup router rather than the path to the Master router. If you
enable the Brocade implementation of VRRP to suppress the VRRP Backup routers from
advertising the backed-up interface in RIP, other routers learn only the path to the Master router for
the backed-up interface.
Authentication
The Brocade implementations of VRRP and VRRP-E can use simple passwords to authenticate
VRRP and VRRP-E packets. VRRP-E can also use HMAC-MD5-96 to authenticate VRRP-E packets.
VRRP and VRRP-E authentication is configured on the router interfaces. The VRRP authentication
configuration of every router interface must match. For example, if you want to use simple
passwords to authenticate VRRP traffic within a router, you must configure VRRP simple password
authentication with the same password on all of the participating router interfaces.