Service nodes, which are usually servers, provide address resolution and routing services to clients , which represent the leaves of the tree. The service node assigns VIP addresses to clients. When a client is powered on, it broadcasts a request for servers, and all servers that hear the request respond. Client subnetwork addresses typically are assigned sequentially, starting with 8001H. Server subnetwork addresses are always 1. Clients always choose their own server as a first-hop router, even if another server on the same cable provides a better route to the ultimate destination.
Clients can learn about other routers by receiving redirect messages from their own server.
The servers themselves send routing updates to other servers periodically to alert other routers to changes in node addresses and network topology. If the current server is the destination, the server handles the request appropriately. If the packet is a broadcast, the current server checks to see whether the packet came from the least-cost path. If not, the packet is discarded. If so, the packet is forwarded on all interfaces except the one on which it was received.