[CAP] update segments

[Art Botterell]

Mick -

We wrestled with this and ultimately went with the simple approach...  
an update or a cancel refers to the entire message, so if you want  
some parts to persist you use an update that includes all the new and/ 
or continuing content.  That's consistent with our general philosophy  
of allowing receiving clients be as simple as possible by having  
senders do as much of the logic as they can, once and for all.  It  
also ensures that nodes that joined the net since the original  
message will be able to go forward based on the update alone.

- Art


On Sep 20, 2006, at 9/20/06 12:19 PM, Mick Jagger wrote:

> Hi,
> 	In working(slowly) on an implementation guide for CAP to be added  
> to the CAP cookbook, there are some cases that I wanted to get this  
> group's opinion on.  What are the best methods to handle update and  
> cancel messages that add or remove a data segment like area or  
> resource?
> 	For example, an alert is issued for area A.  Then an update is  
> issued for the same alert that now includes area B and C.  Should a  
> seperate alert message go out for B and C, or just an update to the  
> original that includes A, B, C?  Now, how about a cancel message  
> for just area B.  Should it be an actual cancel message for B, or  
> an update for just area B with the description saying that its  
> cancelled for that area, or an update to A, B, C saying that B is  
> not longer covered and future messages drop the B area?
> 	I wanted to get a sense of the actual intended method of handling  
> these situations and the methods any current implementations have  
> chosen.  Thanks,
>
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