[SIPForum-discussion] need help from people who know all the rules by heart

[Michael Trank]

I have a situation where some sessions between a UAC and a UAS look like 
this:

It looks like this:

       UAC                                    UAS

      INVITE         ===>>
      200 OK    <<===
      ACK         ===>>

some seconds pass by....

      Re-INVITE   <<====  ( with "BlackHole" SDP )  
      100 Trying   ===>
      BYE        ===> 
       100 Trying    <===  ( provisional for BYE  )
        BYE      ===>
       100 Trying    <===  ( provisional for BYE  )
       BYE      ===>
       100 Trying    <===  ( provisional for BYE )
       BYE      ===>
       100 Trying    <===  ( provisional for BYE  )
       BYE      ===>
       100 Trying    <=== ( provisional for BYE  )


and thats it, things kind of get stuck like this. The BYE's stop, but 
the call finished somewhat un-gracefully.

What is supposed to happen  when  a  re-INVITE gets sent in one 
direction and  a BYE gets sent in the other, ignoring the re-INVITE?