Resend Request and LogOut Response

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1

Imported from previous forum

2

I have got this situation :
Part A ask to Part B logging:

A:<-- Logon (SeqNm=50)
B:–> Logon (SeqNum=84)
B:–> Resend (SeqNum=85, asking for BeginSeqNum=48 and EndSeqNum=49)
A:<-- Logout (SeqNum=51, Error=Seq error, reporting the Part B Logon SeqNum=84)

Why Part A sends a Logout ?
Shouldn’t Part A implement one of three possible Resend procedures ?

Is possible that Part B sends LogOut because the Logon SeqNum is less than that one expected ?
Anyway, is that correct ?

Thanks
Alessandro Fiorilli

3

I guess the answer to your question depends upon what B’s last MsgSeqNum value sent to A was before the scenario you described below.

If B had sent A a message with MsgSeqNum > 84 (TOO LOW), then termination of the connection due to too low of a MsgSeqNum is correct.

If A received B’s last MsgSeqNum of 83 (NO GAP), then B’s behavior does not look correct.

If A received B’s last MsgSeqNum < 83 (SEQ NUM GAP), then B should have issued a ResendRequest.

Note also that the Technical Committee recommends using infinity vs. a specific end value as your EndSeqNum on ResendRequest scenarios such as this.

> I have got this situation :
> Part A ask to Part B logging:
>
> A:<-- Logon (SeqNm=50)
> B:–> Logon (SeqNum=84)
> B:–> Resend (SeqNum=85, asking for BeginSeqNum=48 and EndSeqNum=49)
> A:<-- Logout (SeqNum=51, Error=Seq error, reporting the Part B Logon SeqNum=84)
>
> Why Part A sends a Logout ?
> Shouldn’t Part A implement one of three possible Resend procedures ?
>
> Is possible that Part B sends LogOut because the Logon SeqNum is less than that one expected ?
> Anyway, is that correct ?
>
> Thanks
> Alessandro Fiorilli
>