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FAST Protocol
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Re: Fast SCP
Rolf Andersson / Pantor Engineering
1 Aug 2008 3:57AM ETFAST 1.1 section 10 (transfer Encoding) specifies that a FAST stream consists of a sequence of messages or a stream of blocks. A block is a sequence of one or more messages. One of the reasons for including blocks into the std was to enable skipping of a sequence of messages.
The block construct could be used to make it possible to add fields at the end of a message. there is still a question of how operators may be used for added fields. The current rules for pmap content must be reviewed and possibly updated.
/Rolf
> First of all thanks to everybody for chipping in and commenting on
> my problem.
>
> The most interesting case (which we have had in the past) is the
> addition of a field that is linked to functionality which can optionally
> be used by the member. It would be great if a member would not be forced
> to update the template and simply ignore the new field(s). This is the
> only way he can avoid retesting of his application. If the member needs
> the new functionality, he has to test this anyway and then a new
> template is not an issue.
>
> For more complex changes such as field deletions, operator changes, data
> type changes, I do not see an actual benefit in terms of being able to
> skip re-testing.
>
> Regards, Hanno.
>
> > our posts crossed. So you're suggesting a message length to handle
> > *added* fields. So what about field operator changes, added fields to
> > repeating groups, etc?
> >
> > > <-- would be a is_a relationship.
> > > i/o implement this one would need , as suggested by Hanno, to carry
> > > the length so that slicing can be operated properly
> > >
> > >> No.
> > >>
> > >> Given T1 <-- T2 and M encoded with T2
> > >>
> > >> If I have both T1 & T2, I can chose either.
> > >>
> > >> If I don't need the extra data added per T2, I can chose to use T1.
> > >>
> > >> By definition of T1 <-- T2 then a message encoded with T2 *must* be
> > >> decodable by T1.
> > >>
> > >> If you decode M with T1, then you will "slice" your message
> > >> somewhat, but that might be something you want, or still better
> > >> that nothing when you don't have T2.
> > >>
> > >> This would allow senders to "evolve" their templates, giving the
> > >> choice to receiver to use or not this "evolution"
> > >>
> > >>> Hm, I'm still not sure how this should be used. If you have both
> > >>> T1 and T2 then you can use the right template to decode. If you
> > >>> don't have T2 then you're in trouble as T1 doesn't contain the
> > >>> info need? Am I missing something?
> > >>>
> > >>> /Rolf
Fast SCP Dimitry London / Morgan Stanley 30 Jul 2008 10:16PM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 31 Jul 2008 3:28AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 31 Jul 2008 6:17AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 31 Jul 2008 9:05AM ET Re: Fast SCP Hanno Klein / Deutsche Börse Systems 31 Jul 2008 10:06AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 31 Jul 2008 10:15AM ET Re: Fast SCP Greg Orsini / Cameron Systems 31 Jul 2008 11:44AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 1 Aug 2008 2:06AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 1 Aug 2008 2:39AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 1 Aug 2008 3:13AM ET Re: Fast SCP Hanno Klein / Deutsche Börse Systems 1 Aug 2008 3:33AM ET Re: Fast SCP
Rolf Andersson / Pantor Engineering 1 Aug 2008 3:57AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 1 Aug 2008 4:10AM ET Re: Fast SCP Rolf Andersson / Pantor Engineering 1 Aug 2008 3:06AM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 1 Aug 2008 6:28AM ET Re: Fast SCP Jacob Northey / The LaSalle Technology Group 1 Aug 2008 8:21AM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 1 Aug 2008 9:33AM ET Re: Fast SCP Greg Orsini / Cameron Systems 1 Aug 2008 10:01AM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 1 Aug 2008 10:16AM ET Re: Fast SCP Greg Orsini / Orc Software w/CameronFIX 1 Aug 2008 10:32AM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 1 Aug 2008 10:58AM ET Re: Fast SCP Jean-Marie Sulmont / RTS 31 Jul 2008 10:19AM ET Re: Fast SCP Jean-Marie Sulmont / RTS 31 Jul 2008 10:41AM ET Re: Fast SCP David Rosenborg / Pantor Engineering AB 31 Jul 2008 11:10AM ET Re: Fast SCP Dimitry London / Morgan Stanley 7 Aug 2008 10:53PM ET
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