The TTP mode. The associated interface, itsSrcTtpLocalIf,
must have the capability to support the property when the
administrative state of the TTP is set to up.
unicast(1). The trail termination point shall establish a
unicast connection.
multicast(2). The trail termination point shall established a
multicast connection. It will set the corresponding
capability in chmgrODescrCapabilites.
compatible(3). The trail termination point shall be
compatible with early systems releases, and is acting as to
connect to a remote system with an earlier system release.