Quanta Cloud Technology QuantaMesh QNOS5, Configuration Manual

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7.3.1.3. VRRP Accept Mode
The accept mode allows the switch to respond to pings (ICMP Echo Requests) sent to the VRRP virtual IP
address. The VRRP specification (RFC 3768) indicates that a router may accept IP packets sent to the virtual
router IP address only if the router is the address owner. In practice, this restriction makes it more difficult
to troubleshoot network connectivity problems. When a host cannot communicate, it is common to ping the
host's default gateway to determine whether the problem is in the first hop of the path to the destination.
When the default gateway is a virtual router that does not respond to pings, this troubleshooting technique
is unavailable. In the QNOS-based switch VRRP feature, you can enable Accept Mode to allow the system to
respond to pings that are sent to the virtual IP address.
This capability adds support for responding to pings, but does not allow the VRRP Master to accept other
types of packets. The VRRP Master responds to both fragmented and un-fragmented ICMP Echo Request
packets. The VRRP Master responds to Echo Requests sent to the virtual router's primary address or any of
its secondary addresses.
Members of the virtual router who are in backup state discard ping packets destined to VRRP addresses, just
as they discard any Ethernet frame sent to a VRRP MAC address.
When the VRRP master responds with an Echo Reply, the source IPv4 address is the VRRP address and
source MAC address is the virtual router's MAC address.
7.3.1.4. VRRP Route and Interface Tracking
The VRRP Route/Interface Tracking feature extends VRRP capability to allow tracking of specific routes and
interface IP states within the router that can alter the priority level of a virtual router for a VRRP group.
VRRP interface tracking monitors a specific interface IP state within the router. Depending on the state of
the tracked interface, the feature can alter the VRRP priority level of a virtual router for a VRRP group.
Note: An exception to the priority level change is that if the VRRP group is the IP address owner, its
priority is fixed at 255 and cannot be reduced through the tracking process.
With standard VRRP, the backup router takes over only if the router goes down. With VRRP interface tracking,
if a tracked interface goes down on the VRRP master, the priority decrement value is subtracted from the
router priority. If the master router priority becomes less than the priority on the backup router, the backup
router takes over. If the tracked interface becomes up, the value of the priority decrement is added to the
current router priority. If the resulting priority is more than the backup router priority, the original VRRP
master resumes control.
VRRP route tracking monitors the reachability of an IP route. A tracked route is considered up when a
routing table entry exists for the route and the route is accessible. When the tracked route is removed from
the routing table, the priority of the VRRP router will be reduced by the priority decrement value. When the
tracked route is added to the routing table, the priority will be incremented by the same.
7.3.2. VRRP Configuration Example
This section contains the following VRRP examples:

VRRP with Load Sharing