Observium (as of 0.15.9.6997) displays ifAlias / ifDescr as label for Brocade Fabric OS SAN switches. Brocade, however, uses “portnames”, which can be found at OID 1.3.6.1.4.1.1588.2.1.1.1.6.2.1.36

Is this per design or just because very few have Fabric OS devices in Observium?