Release L.10.07 Enhancements; Uni-Directional Link Detection (Udld) - HP ProCurve J8766A Release Note

Enhancements

Release L.10.07 Enhancements

Release L.10.07 Enhancements
Release L.10.07 includes the following enhancements:
Added support for Unidirectional Fiber Break Detection.
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Uni-Directional Link Detection (UDLD)

Uni-directional Link Detection (UDLD) monitors a link between two ProCurve switches and blocks
the ports on both ends of the link if the link fails at any point between the two devices. This feature
is particularly useful for detecting failures in fiber links and trunks. Figure 6 shows an example.
Scenario 1 (No UDLD): Without UDLD, the switch ports
remain enabled despite the link failure. Traffic continues to
be load-balanced to the ports connected to the failed link.
Scenario 2 (UDLD-enabled): When UDLD is enabled, the
feature blocks the ports connected to the failed link.
Trunk
ProCurve
Switch
Figure 6. UDLD Example
In this example, each ProCurve switch load balances traffic across two ports in a trunk group. Without
the UDLD feature, a link failure on a link that is not directly attached to one of the ProCurve switches
remains undetected. As a result, each switch continues to send traffic on the ports connected to the
failed link. When UDLD is enabled on the trunk ports on each ProCurve switch, the switches detect
the failed link, block the ports connected to the failed link, and use the remaining ports in the trunk
group to forward the traffic.
Similarly, UDLD is effective for monitoring fiber optic links that use two uni-direction fibers to
transmit and receive packets. Without UDLD, if a fiber breaks in one direction, a fiber port may
assume the link is still good (because the other direction is operating normally) and continue to send
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Third Party
Switch
Link Failure
ProCurve
Switch