This object specifies the type of network service provided by
the target service:
'other'
The implementation of this MIB module does not recognize
the configured network service.
'none'
The target subscriber service does not provide a network
service to subscribers sessions.
'local'
The target subscriber service provides local termination
for subscriber sessions.
'vpdn'
The target subscriber service provides a Virtual Private
Dialup Network service for subscriber sessions.
This column is valid only if the 'networkSrv' bit of the
corresponding instance of cdtSrvValid is '1'.