Product guide

Router Redundancy Using XRRP
Terminology
■ Fail-Back Router: In a given protection domain, this is the XRRP-
enabled router that takes over the routing functions transferred from its
XRRP peer in the domain when the peer loses access to one or more of
its XRRP VLANs. The fail-back router must have access to all of its XRRP
VLANs at the time of the fail-over. See also Fail-Over Router.
■ Fail-Over Router: In a given protection domain, this is an XRRP-enabled
router that loses access to one or more of its XRRP VLANs, causing a fail-
over of its routing functions to the other XRRP router (peer) in the domain.
The peer must have access to all of its XRRP VLANs at the time of the fail-
over, and is designated as the “fail-back” router. See also Fail-Back
Router.
■ Infinite Fail-Back: The operating mode of an XRRP router in which the
router does not automatically allow fail-back when its peer in the protec-
tion domain recovers from a fail-over condition.
■ Primary Control: The mode in which the XRRP VLANs configured on a
router in a protection domain are controlled by that router.
■ Secondary Control: The mode in which the XRRP VLANs configured on
one router in a protection domain are controlled by the other (fail-back)
XXRP router in the domain. A fail-back router advertising XRRP packets
for the failed (peer) router’s backed-up IP addresses has both primary and
secondary control of the XRRP VLANs in the domain.
■ Permanent Control: The mode associated with infinite fail-back in
which a fail-over has occurred in a protection domain and the resulting
fail-back router has both primary control and secondary control of the
XRRP VLANs in the domain. See also Primary Control and Secondary
Control.
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