Imported from previous forum
[ original email was from Steven Grossman - steven.grossman@transacttools.net ]
The SCP 1.1 Template Definition message is SCP’s representation of the normative template definition defined in the FAST 1.1 specification. How does the SCP specification intend to deal with the introduction of FAST 1.2 where, say, a new operator or field instruction is introduced? How will an SCP implementation be able to take advantage of the new template definition? If a new version of SCP is required, will an implementation need to handle any new additions to the SCP session? Will there be a way to keep the old SCP session while using the new template structures?
Steven
New versions of SCP will have all its messages and templates within that version. My suggestion is that if a template is structurally compatible and the semantics of its message type are compatible with a previous version, the template identifier should be retained. An exception from this rule is the Hello message that should always have fresh a TID. The intention is that a decoder should be able to identify the overall SCP version in play by locking at just the Hello message.
It is up to a particular decoder implementaton if it can handle multiple versions. It is further up to future revisions of the SCP spec to decide through conformance rules if mixed versions are allowed.
/David
The SCP 1.1 Template Definition message is SCP’s representation of the
normative template definition defined in the FAST 1.1 specification. How
does the SCP specification intend to deal with the introduction of FAST
1.2 where, say, a new operator or field instruction is introduced? How
will an SCP implementation be able to take advantage of the new template
definition? If a new version of SCP is required, will an implementation
need to handle any new additions to the SCP session? Will there be a way
to keep the old SCP session while using the new template structures?Steven