HP ProCurve 5300xl Series Management Manual page 580

Router Redundancy Using XRRP
Overview of XRRP Operation
Figure 12-5.Standard XRRP Fail-Over with Total VLAN Failure
12-8
Standard Fail-Over. In the multiple-VLAN situation in which all communi-
cation between the routers in the Protection Domain is lost, the standard
XRRP fail-over occurs. As shown in figure 6, Router-2 has lost communications
on all of its XRRP virtual router interfaces. In this case, Router-1 will no longer
hear XRRP packets coming from Router-2. If that condition persists for 3
advertisement intervals, Router-1 then takes over all of the virtual routers from
Router-2.
If the cause of the total VLAN access failure, as shown in figure 17-5, is because
of a complete router failure (due to building power loss, for example), the
router that remains active will wait for the three XRRP advertisement intervals
and will then take control of the failed router's IP and MAC addresses. If both
routers are still active but the all network connections between them have
been severed, then both routers will take over for each other. This means that
identical IP and MAC addresses will exist on both routers, but in a completely
severed network, there will be no duplicated MAC or duplicate IP address
errors.