+- Provide ways to:
+ + set the IP address, possibly based on the peer's identity
+ + have external checking of PAP user/password, CHAP response
+ + supply the PAP user/password, CHAP secret
+ + decide which tty to use (locking, DTR issues)
+
+- Integrate callback stuff?
+
+- Implement link quality monitoring
+
+- Implement other network control protocols