Defines the type of VDSL physical line entity that exists, by defining whether and how the line is channelized. If the line is channelized, the value will be other than noChannel(1). This object defines which channel type(s) are supported. Defined values are: noChannel(1) fastOnly(2) interleavedOnly(3) fastOrInterleaved(4) fastAndInterleaved(5) Note that 'slow' and 'interleaved' refer to the same channel. In the case that the line is channelized, the manager can use the ifStackTable to determine the ifIndex for the associated channel(s).