At the meeting last week in Norfolk, the BACnet/IP working group
discussed JB-016-1, a document that outlines some usage scenarios and
requirements for a new point-to-point protocol for BACnet that uses SSL.
The attached document (JB-016-2) reflects that discussion, with
significant changes highlighted.
There was some discussion in Norfolk about the differences between SSL
and TLS. Here is what RFC 2246 says: "This document and the TLS
protocol itself are based on the SSL 3.0 Protocol Specification as
published by Netscape. The differences between this protocol and SSL 3.0
are not dramatic, but they are significant enough that TLS 1.0 and SSL
3.0 do not interoperate (although TLS 1.0 does incorporate a mechanism
by which a TLS implementation can back down to SSL 3.0)." It seems
reasonable for BACnet/SSL to be designed to support both SSL and TLS as
I hope to have a complete design document for review at our meeting in
January 2006. I would appreciate input from people who have some
knowledge about the requirements or design issues.
- Jim Butler