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-rw-r--r-- | proposals/340-packed-and-fragmented.md | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/proposals/340-packed-and-fragmented.md b/proposals/340-packed-and-fragmented.md index f760e0e..cd98cfd 100644 --- a/proposals/340-packed-and-fragmented.md +++ b/proposals/340-packed-and-fragmented.md @@ -269,8 +269,23 @@ conflux bundle. ### An exception for `DATA`. -Data messages may not be fragmented. (There is never a reason to do -this.) +Data messages may not be fragmented. When packing data into a cell containing +other messages is desired, the application can instead construct a DATA message +of an appropriate size to fit into the remaining space. + +While relaxing this could simplify the implementation of opportunistic packing +somewhat (by allowing code that constructs `DATA` messages not to have to know +about packing or fragmentation), doing so would have several downsides. + +First, on the receiver side a naive implementation that receives the first cell +of a fragmented `DATA` message would not be able to pass the data in that +fragment on to the application until the remaining cells of that message are +received. An optimized implementation might choose to do so, but that +complexity seems worse than the complexity we'd be avoiding by allowing `DATA` +fragmentation in the first place. + +Second, as with any sort of flexibility permitted to implementations, allowing +flexibility here adds opportunities for fingerprinting and covert channels. ### Extending message-length maxima |