With CVS's pserver, you are required to log in to the server (using the cvs login command) before performing any read or write operation—you sometimes even have to log in for anonymous operations. With a Subversion repository using Apache httpd or svnserve as the server, you don't provide any authentication credentials at the outset—if an operation that you perform requires authentication, the server will challenge you for your credentials (whether those credentials are username and password, a client certificate, or even both). So if your repository is world-readable, you will not be required to authenticate at all for read operations.

相对于CVS，Subversion会一直在磁盘(在你的~/.subversion/auth/目录)缓存凭证，除非你通过--no-auth-cache选项告诉它不这样做。

这个行为也有例外，当使用SSH管道的svnserve服务器时，使用svn+ssh://的URL模式这种情况下，ssh会在通道刚开始时无条件的要求认证。