Re: M2PA - SIB vs. SCTP association level flow-control

Stanislav,

Please see comments inline...

Stanislav Ivanovich wrote:                                      (Tue, 09 May 2006 04:14:30)
> 
>    Hello colleagues,
> 
> 
> 
>    M2PA  RFC defines the protocol which is to provide the MTP L2 services
>    and  functions together with underlying SCTP protocol. I see that most
>    important  MTP  L2  features  (like  error  detection  and correction,
>    supervision,  alignment  etc...)  are replaced with corresponding SCTP
>    functions.
> 
> 
> 
>    However  I am wondering why would one need SIB (or in M2PA terminology
>    "Link Status Busy") if:
> 
> 
> 
>    a) the relationship between SCTP association and M2PA link is 1:1
> 
> 
> 
>    b)  SCTP  provides the means to stop acknowledging incoming traffic if
>    the  local  user  stops to read the messages (i.e. local user function
>    does  not  invoke  recvmsg() on the socket API thus causing filling of
>    the receiving buffer at local SCTP thus causing stop of acknowledgment
>    of  incoming  traffic  which in turn causes closing of the cwnd at the
>    remote SCTP at the sender side)
> 
> 
> 
>    I am asking this question since maybe I missed something...

M2PA provides its own acknowlegdement of messages separate from SCTP.  This
is for a number of reasons.  SIB is necessary for the receiver to indicate
that it might not acknowledge a message within T7.

> 
> 
> 
> 
> 
>    I  am  also  wondering  is  there  any preliminary version of the M2PA
>    Implementor's guide available?

Not that I know of.

--brian


-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/