IBM Nways 8260 Manual page 193

Because these modules do not have switching capabilities, the URA cannot be
switched onto the faulty segment. In order to execute the unwrapping tests, the
module must wrap the backplane and wrap all the lobe ports. This allows the
URA to be on a segment isolated with the trunk under the test. Obviously, this is
disruptive to the stations on the module, so it is not desirable to try this every 5
minutes.
Note
URA cannot transmit Downstream Converter Presence because the Recovery
ASIC MAC cannot transmit on token. Also, if LNM is on the ring, it does not
get a MAIN RING PATH WRAPPED TO BACKUP alert.
Chapter 8. 8260 Token-Ring Support
171