This attribute indicates the current state of the MSC/IWF Interface
Protocol (MIP) Message Router (MMR) for an IWF element. This
attribute has one of the following values:
idle: Startup state of IWF element.
setup: This call half is being set up.
active: This call half has been connected by both the MTX and IWF
and is active.
release: This call half is being released.