Xrrp - Router Redundancy Protocol - HP ProCurve 5308XL-48G Supplementary Manual

Other ProCurve switches that support Switch Meshing, such as the ProCurve Switch 4000M
family, will work together in a mesh with the ProCurve 5300xl Switch Series. There are a few
corner case caveats in this type of mixed environment that are covered in the ProCurve 5300xl
documentation. The ProCurve 5300xl documentation can be found at:
under the Technical Support section.
A white paper with more details on Switch Meshing can be found in the information library on
ProCurve's networking web site at http://www.procurve.com.
XRRP – Router Redundancy Protocol
One form of high availability in a Layer 3 environment is having two routing switches back each
other up. In the event of a connection failure with one of the routing switches, the other routing
switch transparently takes over the routing function. XRRP, the XL Router Redundancy Protocol,
provides the mechanism in the ProCurve 5300xl Switch Series routing switches for this backup
functionality.
Similar in concept to VRRP (Virtual Router Redundancy Protocol), XRRP presents a virtual router
to the end node connections whose IP and MAC address can transition from the master
ProCurve 5300 Switch to the backup ProCurve 5300 Switch on master ProCurve 5300 Switch
interface failure. Since the end node connections are tied to the virtual router using the virtual
router IP and MAC addresses, they are unaware as to whether the actual physical routing
services are being provided by the master ProCurve 5300 Switch, or, after a switch-over, to the
backup ProCurve 5300 Switch, making any switch-over transparent to the end nodes. An XRRP
interface failure is defined as the inability of the master physical interface in the 5300 pair to be
heard by the backup interface. This could be caused by a cable failure, module failure, whole
5300 failure, or operator error (such as a disconnected cable).
Some XRRP specifications:
•
Number of physical routers in a backup group (XRRP calls this a 'protection domain'): 2
•
Number of protection domains allowed per VLAN: 16
•
Time to failure detection and switchover: default – 15 seconds. Minimum time by making a
configuration change – 3 seconds. If a VLAN is lost on one of the 5300 pairs, but the 5300
doesn't go down, fail-over occurs in under 1 second as the 5300 with the failed VLAN reports
the loss directly to the other 5300 via a different VLAN.
•
Backed-up interfaces should be configured identically between the routers. XRRP checks and
warns if interface configurations do not match.
•
Master interfaces can be split between the two 5300 switches, allowing a split of traffic
between the two 5300s under normal network conditions.
•
If a failure is detected on any master interface, all the XRRP master interfaces on that 5300
are switched over to the back-up router. This allows easier troubleshooting, or module or box
replacement. When all interfaces on the failed 5300 are restored, the master relationship is
re-established as it was before the fail-over. There is a time interval (XRRP fail back – default
10 seconds, configurable to 999 seconds) before master re-establishment can take place to
prevent master interface flapping due to interfaces that may be going up and down.
•
When infinite fail-back is enabled, the back-up router does not automatically allow fail-back
when its peer recovers from a failed condition. This is useful in cases where a fail-over/fail-
back cycle occurs repeatedly causing frequent network disruptions.
•
Those interfaces not defined as part of the XRRP set on a 5300 will continue to run on that
5300 (unless, of course, the whole 5300 is down) even as the XRRP interfaces switch over to
the backup 5300. This has value for low priority interfaces where the cost of redundant
resources across two 5300s for these interfaces is not justified.
•
If a 5300 Management VLAN is enabled it cannot be defined as an XRRP interface – SNMP
management requests to a particular 5300 need to go to that physical switch regardless of
fail-over status.
XRRP does not interoperate with VRRP, but can coexist in a VRRP environment without
interference.
For more details see the ProCurve 5300xl Switch Series documentation located at:
http://www.procurve.com under the Technical Support section.
http://www.procurve.com
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