Subject: out of order commands

From: Manish Rao <[email-masked]>
Date: Wed, 1 Dec 1999 16:50:04 -0700

Hi!
    I need to know how to resolve the following case where commands are sent out of order.

Create Connection on both sides (local and remote) has suceeded.  The Call Agent now applies ring-back tone to the local end (S: v).  This message does not reach the gateway (UDP loss), and hence will be retransmitted after a certain time.  Mean while,  the remote end goes off hook, and the MDCX is applied to the local end to put the endpoint in full duplex mode, ie., the call is now up.  X milli-seconds later, the retransmission of the ring-back signal-request occurs, and now the gateway applies ring-back tone on the already established call, which is an error.
    My question is: should the call-agent maintain state such that when a ring-back request has been sent but response has not yet been received, and the remote end goes off-hook, remove the ringback RQNT from the retransmission queue, and just apply the MDCX to establish the call; or, should the ringback retransmission go ahead as planned, and the gateway recognizes that a call is currently up, and ignores the "late" RQNT for ring-back.

Thanx
Manish

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<DIV><FONT face=Arial size=2>Hi!</FONT></DIV>
<DIV><FONT face=Arial size=2>&nbsp;&nbsp;&nbsp; I need to know how to resolve
the following case where commands are sent out of order.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>Create Connection on both sides (local and remote)
has suceeded.&nbsp; The Call Agent now applies ring-back tone to the local end
(S: v).&nbsp; This message does not reach the gateway (UDP loss), and hence will
be retransmitted after a certain time.&nbsp; Mean while,&nbsp; the remote end
goes off hook,&nbsp;and the MDCX is applied to the local end to put the endpoint
in full duplex mode,&nbsp;ie., the call is now up.&nbsp; X milli-seconds later,
the retransmission of the ring-back signal-request occurs, and now the gateway
applies ring-back tone on the already established call, which is an
error.&nbsp;</FONT></DIV>
<DIV><FONT face=Arial size=2>&nbsp;&nbsp;&nbsp; My question is: should the
call-agent maintain state such that when a ring-back request has been sent but
response has not yet been received, and the remote end goes off-hook, remove the
ringback RQNT from the retransmission queue, and just apply the MDCX to
establish the call; or, should the ringback retransmission go ahead as planned,
and the gateway recognizes that a call is currently up, and ignores the "late"
RQNT for ring-back.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>Thanx</FONT></DIV>
<DIV><FONT face=Arial size=2>Manish</FONT></DIV></BODY></HTML>