X.25 addresses and Frame Relay DLCIs can be mapped in
two different ways: by using IPX network numbers
as previously implemented (OldNbrMap) or by using the
Ethernet address of the remote NETBuilder currently
implemented (NewNbrMap). This option is set to
NewNbrMap by default, but OldNbrMap should be selected
to interoperate with a neighbor running earlier than
5.0 bridge/router software.