Re: [tsvwg] comments draft-tuexen-tsvwg-sctp-prpolicies-01

[Michael Tuexen <[e-mail]>]

On Jul 10, 2013, at 11:48 AM, Jamal Hadi Salim <[e-mail]> wrote:

> 
> Hi Michael,
> 
> On Wed, Jul 10, 2013 at 3:42 AM, Michael Tuexen <[e-mail]> wrote:
> 
> Assume the sender sends a user message which is approximately of size 3*MTU.
> So SCTP will fragment it into 3 DATA chunk and send them. If the user
> has specified that the number of retransmissions is limited to 0 and
> the last fragment gets lost in the network, the sender will increment
> sprstat_abandoned_sent.
> 
> Ok,  so the last fragment essentially doesnt get acknowledged before we 
> abandon ship. And the other stat indicates we abandoned while we still had some
> sitting locally. Is the intersection of the two (some are sent but not acked and
> some are still sitting locally) implying both stats will be incremented?
> 
> Other than the perceived ambiguity -  why do i care to know about the
> two types of abandoned messages in a user app? I  will have to sum
> those two, so why not just give me one stat?
>  
> BTW: the doc will benefit from such a small description as you gave me
> above.
The new revision contains some clarification:
http://tools.ietf.org/html/draft-tuexen-tsvwg-sctp-prpolicies-02

Best regards
Michael
> 
> What will happen at the receiver side if you assume that the first two
> fragments have been received. If partial delivery was started, you will
> get a SCTP_PARTIAL_DELIVERY_EVENT event indicating SCTP_PARTIAL_DELIVERY_ABORTED.
> Without partial delivery being started, the receiver could also drop the
> first part of the message.
> 
> 
> You answered the essence of my question.
> Silly follow up: I am assuming that event will come with an EOR?
> To use your example (at receiver):
> EPOLLIN, recvmsg chunk1, chunk2, EAGAIN
> EPOLLIN, recvmsg SCTP_PARTIAL_DELIVERY_EVENT, EOR
> 
> cheers,
> jamal