This attribute specifies the type of framing protocol that will be
used for frames transmitted to the link interface and received from
the link interface. If the value of this attribute is set to the default
interrupting, then a Proprietary hdlc protocol is used which allows
for voice cells to interrupt transmission of data frames, transmit the
voice cell, and then continue transmitting the data frame. If the
value of this attribute is set to hdlc, then the standard hdlc procotol
is used for the sequential transmission of individual frames.