/usr/lib/lua/luci/model/cbi/admin_network/proto_ppp.lua
/usr/lib/lua/luci/model/cbi/admin_network/proto_pppoe.lua
/usr/lib/lua/luci/model/cbi/admin_network/proto_pppoa.lua
/usr/lib/lua/luci/model/network/proto_ppp.lua
