20.1.3 IEEE 802.3 ah/UDLD important reminder for use
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(1) When a device that does not support IEEE802.3ah/OAM function is connected between devices for which IEEE802.3ah/UDLD function is set
Because a standard switch does not forward control frames used by IEEE 802.3ah/OAM functionality, information cannot be transmitted between switches, and a unidirectional link failure is detected on a port configured with the efmoam active udld configuration command. Accordingly, IEEE 802.3ah/UDLD functionality cannot be used.
(2) When a relay device such as a media converter is connected between devices for which IEEE802.3ah/UDLD function is set
If a media converter that does not automatically disconnect the link when the other link is disconnected is installed between switches, recognition of the link status varies between the switches. Accordingly, a unidirectional link failure is detected even if the remote device is not operating on a port configured with the efmoam active udld command. When you attempt recovery from a failure, you must synchronize both switches, making operation more difficult. Use a media converter that automatically disconnects the link status if the other link is disconnected.
(3) Connecting with UDLD functions of other companies
The IEEE 802.3ah/UDLD functionality of the Switch and the UDLD functionality of other manufacturers' switches cannot be connected because UDLD functionality specifications differ by manufacturer.