Something improper with ASP state change procedures.

Hi All,

We are seeing some strange in the M3UA ASP state change procedures.  Please
find the description of the problem below.

ASP                                                              SGP
=======================================
ASPUP               -------------->  Processes ASPUP and sends ASPUP_ACK

Move ASP to
INACTIVE state   <-------------   ASPUP_ACK

SCTP-SACK
for ASPUP_ACK  ------------->  Missed or lost in the network

ASPAC               -------------->  Processes ASPAC and sends ASPAC_ACK

Move ASP to
ACTIVE state      <-------------   ASPAC_ACK

 SCTP-SACK
for ASPAC_ACK  ------------->  Missed or lost again in the network

 Move ASP to
INACTIVE state   <-------------   SCTP layer at SGP retransmits the
ASPUP_ACK, ASPAC_ACK because of lost SACKs.
because of
ASPUP_ACK
in ACTIVE state

SCTP-SACK        ------------->  Reached the SCTP layer of SGP

In the above behavior the M3UA at SGP thinks that the ASP is in ACTIVE state
whereas it is not the case.  Since ASP is in INACTIVE state, all the data
packets that were sent by SGP will be dropped (without sending any error
message back to network).  The above problem will lead to a potential
message loss in the network.

Considering the above behavior, I think the state machine should be tuned
accordingly.

Please pass on the comments on this.

Thanks & Regards,
Naveen.

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