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FAST Protocol
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Re: Fast SCP
David Rosenborg / Pantor Engineering AB
1 Aug 2008 9:33AM ETYes, it would work in some situations, but it requires you to use blocks in general which might not be desired. Furthermore, you'd have to restrict a block to contain exactly one message (at least in situations where you know you're using extended templates (as percieved by the receiver, which might not always be possible to know)).
Also, the constraint list would have to be extended to prohibit the bytes that constitute the extension from looking like the start of a message, which is rather tricky in the general case. It's probably solvable by always adding two pad bytes at the start of the extension the first always having the value 0xc0, and the second having the value of some unused tid.
This last constraint is not necessary if you enforce the one message per block constraint for all messages. But if a decoder make use of this constraint it will suddenly behave in a non standard way.
/David
> I think the easiest approach is to create a FAST best practices guide
> that includes instructions for achieving support for multiple message
> template versions at the same time. Summarizing what has been said
> before, this would require:
>
> 1) Length prefixed blocks
> 2) Fields cannot be added to sequences
> 3) Fields can only be added to a
> group if the group is the last field instruction in a template and
> the added fields do not affect the groups use of a presence map (e.g.
> a group that does not need a presence map can only have fields added
> that don't require entries in the presence map).
> 4) New fields cannot use operators that would affect shared
> dictionary values.
>
> Jake
>
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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