Hi, Larger frames than the MTU are not just a problem to Diameter; they also complicate the normal handshake in DTLS which is a bit of a misfit with DTLS delivery semantics.
Since the version is bit-swapped in DTLS, each record can easily be distinguished as being either DTLS or TLS. Then, why not allow the mixing of those records in a stream, and map them differently to the transport protocol? I suppose the records could be marked as being the first and/or last in a large user message, and this could be meaningfully translated to properties and behaviour of the transport. Below the DTLS MTU, information is sent as DTLS, and above it, it is sent as a sequence of TLS frames -- or are rejected, if the transport cannot handle that. Plain TLS could be a special case where the DTLS MTU is set to 0. Datagrams may have a number of meanings, too, that translate to different transport meanings. Diameter differs from RTP in that it wants reliable delivery (which is why it does not carry over UDP) but it is like RTP in that it does not want ordered delivery. Plain TLS applications would present the usecase of reliable ordered delivery. Hopefully helpful, -Rick _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
