4.1 Introduction
Direct TP - a client sends a request to a server, waits (synchronously) for the server to run the transaction and possibly return a reply (e.g., RPC)
Problems with Direct TP
- Server or client-server communications is down when the client wants to send the request
- Client or client-server communications is down when the server wants to send the reply
- If the server fails, how does the client find out what happened to its outstanding requests?
- Load balancing across many servers
- Priority-based scheduling of busy servers