The Port alias column represents ifAlias, whose
description is rather ambiguous. It's same kind of alternative name in addition to ifName and ifDesc.
Anyway, since it does not indicate the physical location of a port, it's probably in some other OID. It's pretty hard to determine what OID it may be though, without having access to the switch.
You mentioned one switch has ports labelled as T1, T2, B1, B2. Could you perhaps run
snmpwalk against that switch and
send me the output?