Landslide only support the figure of section 2 of RFC 4951 as follows:
Two GGSNs acting as LACs and Primary LNS server. One GGSN is mirroring the active GGSN prepared to step in if active GGSN fails. Upon failure of active GGSN, other GGSN steps in and does tunnel recovery AVP (and possibly other AVP per RFC4951) to keep from having to rebuild all the L2TP tunnels from scratch