NLSP is an IPX link state routing protocol that was developed to respond to limitations that arise when implementing IPX RIP and SAP in larger internetworks, particularly over WAN links. Link state routers exchange information about the state of their network connections or links. Using this information, each router can construct the topology of the internetwork and derive routing information.
NLSP offers the following advantages over IPX RIP
Faster convergence of router information tables
First hand routing information
Generates less traffic