Maven: meaning of repository ID

In my POM file, I'm specifying two repositories: ``` <repositories> <repository> <id>myid</id> <url>http://url1</url> </repository> <repository> <id>myid</id> <url>http://url2</url> </repository> </repositories> ``` So, from the Maven documentation, I got the impression that the `id` element should cross-reference with a `settings.xml` `server` entry, to specify authentication information. Both `http://url1` and `http://url2`, in my case, require the very same authentication data; that is why I'm using the same `id` for both. Still, Maven complains, saying that the `id` element must be unique. What gives? What exactly is that purpose of the `id` element? I know (for sure) that Maven uses it to get authentication data - which is why things work when I only specify one repository. Why do I have to duplicate my authentication data? what am I missing?