Specifies the type(s) of authentication, if any, to be negotiated with the peer: none No authentication is negotiated. pap PAP negotiation only. chap CHAP negotiation only. papChap PAP negotiation is attempted first; if fails, attempt CHAP. chapPap CHAP negotiation is attempted first; if fails, attempt PAP. If authentication negotiation is not supported for this PPP interface, then any attempt to explicitely set this object will result in a notWritable error and it will be implicitily set to the DEFVAL on row creation. Setting this object to none(0) will set juniPppLinkConfigAuthenticatorVirtualRouter object to an empty string. This object returns a null(0) value on the get operation. New object juniPppLinkConfigAuthentication2 will reflect the configured values. Setting this object along with the juniPppLinkConfigAuthentication2 object will return an inconsistentValue error.