To understand the differences between NetWare Link Services Protocol (NLSP) and Routing Information Protocol (RIP), you must compare how NLSP devices determine the best route to send a packet with how RIP devices determine the best route. A RIP device assumes that it takes one tick (approximately 1/18th of a second) to cross any network segment. For example, Router 1 in Figure 5 would determine that the FS1 server's internal IPX network was six ticks away from Fred's workstation through path 1. Router 1 would also determine that the FS1 server's internal IPX network was five ticks away from Fred's workstation through path 2.
If Fred sent packets addressed to the FS1 server's internal IPX address, which path would Router 1 use when routing these packets? Router 1 would send Fred's packets through path 2 because this RIP device defined path 2 as only five ticks away.
In reality, however, path 1 is probably faster than Path 2. LAN B is a 100 Mbit/s Fiber Distributed Data Interface (FDDI) ring network, LAN C is a 155 Mbit/s Asynchronous Transfer Mode (ATM) network, and LAN F is a 4 Mbit/s Token Ring network. (See Figure 6.) Because path 1 includes a 100 Mbit/s network and a 155 Mbit/s network, this path is probably much faster than crossing the 4 Mbit/s network of path 2.
Instead of using a tick count, NLSP devices use costs, which are metric values used to differentiate links based on their available throughput. A slower link has a higher cost than a faster link, and the best route has the lowest cost from end to end. (See Figure 7.) Using default costs, an NLSP device would determine that path 1 was the better route and send packets through path 1. (See Figure 8.)