>>>>> "Robert" == Robert Sayre <sayrer@xxxxxxxxx> writes:
Robert> On 9/5/06, Sam Hartman <hartmans-ietf@xxxxxxx> wrote:
>> There are a lot of complexities--for example while we hope
>> every IP stack works with every other IP stack, two machines
>> may not share a common upper-layer protocol or application
>> protocol.
Robert> I worry that such text will encourage sprawling
Robert> specifications that make requirements across many
Robert> layers. I think the example you give is a little
Robert> misleading, since it can be harmful for specifications to
Robert> make requirements on lower layers as well. For example,
Robert> HTTP requires a reliable transport, but I think it's good
Robert> that RFC2616 does not include text like "HTTP
Robert> implementations MUST support TCP/IP, but may support other
Robert> transport protocols".
To be clear, I think I'm documenting what is a long-standing consensus
in the IETF. And I do consider it a bug that HTTP does not require
TCP. It's typical for protocols to require a transport. For example
, I believe SIP requires UDP (and possibly TCP). Kerberos requires
TCP.
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