3. Internationalization Considerations

User-ids or passwords containing characters outside the US-ASCII character repertoire will cause interoperability issues, unless both communication partners agree on what character encoding scheme is to be used. Servers can use the new 'charset' parameter (Section 2.1) to indicate a preference of "UTF-8", increasing the probability that clients will switch to that encoding.

The 'realm' parameter carries data that can be considered textual; however, [RFC7235] does not define a way to reliably transport non-US-ASCII characters. This is a known issue that would need to be addressed in a revision to that specification.

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