[This message was posted by Rolf Andersson of Pantor Engineering <[EMAIL PROTECTED]> to the "FAST Protocol" discussion forum at http://fixprotocol.org/discuss/46. You can reply to it on-line at http://fixprotocol.org/discuss/read/f2e0fd06 - PLEASE DO NOT REPLY BY MAIL.]
I've had a look at the current spec (FAST for OPRA version 02.00 dated January 23, 2008) and I have the following observations: The Template specification is not compliant with FAST 1.1 for the following reasons: - Fields are not in pmap sequence Some pmap slots are unused for each of the specified messages. - The presence of some fields depend on the value of another field. The presence of best bid/ask fields depend on the BBO indicator field - A proprietary framing protocol is used. To add insult to injury, the FAST standard specifies an alternative that provides the same function. In my view, the use of one "generic" template creates much of the compatibility problem. Careful use of a few templates would have made it possible to efficiently use FAST-api 1.0 in a FAST 1.1 compliant manner. I found a way to specify a single FAST template that can be used by a compliant FAST 1.1 decoder to process the individual messages after removing the proprietary framing. The resulting output however contains superfluous incorrect content and additional processing is required to remove the incorrect data generated by the decoder. In summary: While not _impossible_ to use together with a proprietary de-framer, the generic OPRA template prevents recipients from efficiently using a standard FAST 1.1 implementation and requires a custom built decoder in order to get decent performance. /Rolf (on a side-note: The FAST for OPRA specification needs to be reviewed and improved. It is incomplete, ambiguous and contains a number of errors. It doesn't differentiate clearly between FAST 1.0 and 1.1. It mixes snippets of text from the FAST 1.0 and 1.1 specs. The text is partly presented out of context. Some information is not relevant to the current implementation of FAST for OPRA (eg. deltas are not used, but the spec contains a partly erroneous description of delta coding)) > OK. Ignore these individual templates for your evaluation. > Just refer to general template on page 8. > > Thanks, Shwetang [You can unsubscribe from this discussion group by sending a message to mailto:[EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Financial Information eXchange" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/FIX-Protocol?hl=en -~----------~----~----~----~------~----~------~--~---
