This object indicates the source of the mapping.
'configured' indicates that the mapping is manually
configured by user.
'arp' indicates that the mapping is dynamically learnt
from tagged ARP replies.
'localAuthenticated' indicates that the mapping is
dynamically learnt from the device authentication of
a host.
'sxp' indicates that the mapping is dynamically learnt
from SXP (SGT Propagation Protocol).
'internal' indicates that the mapping is automatically
created by the device between the device IP addresses
and the device own SGT.
'l3if' indicates that Interface-SGT mapping is configured
by user.
'vlan' indicates that Vlan-SGT mapping is configured by user.
'cached' indicates that sgt mapping is cached.
Only 'configured' value is accepted when setting this
object.