Cell Relay Archive

["ytq@hwbji.co.cn" <ytq@hwbji.co.cn>]

                                                     (leaf 1)
          ______       |-----------------|          /
         | root |------|                 |  |------/
          ------       | public switch A |--| B   |
                       |_________________|  |____ |\
                                                    \
                                                     (leaf 2)         

      root send SETUP(p-mp) to tell A that the root want to add the
first
 party leaf1,so A send SETUP to B ,B send SETUP to leaf1,leaf1 response
with
 ALERTING,B and A deliver ALERTING to root.
      now,the call link state of A <--> B ,is AlertingReceived state(N7
,U7).
      when root received ALERTING,root send ADD PARTY to A ,A send ADD
PARTY
to B,and B send SETUP to leaf2,leaf2 response with CONNECT,so now,the
call
link state of A<-->B , is ConnectRequest state (N8,U8).
      when A response CONNECT with CONNECT ACK,B must check the party
state of
leaf1 and leaf2 because CONNECT ACK has no EndpointReference ,to decide
which
leaf send CONNECT;otherwise B should remember that leaf2 has just send
CONNECT.
      The party leaf2 state of B( B is the user of public switch A)is
changed from PU2(AddPartyReceivedState) to PU7(Active) after B receive
CONNECT ACK.
      Now ,the party leaf1 state of B( B is the user of public switch
A)is in PU3(AddpartyAlertingDelived state);the call link state between A
and B is ActiveState(N10,U10).

      if CONNECT ACK has EndPointRef,B  quickly know which has just send
CONNECT.

****Notice: Above Discussion is concerned with UNI4.0 and Q.2971,not
UNI3.1.

Thanx all responses.
Thank Cell Relay List Manager.

-- 
                ("`-T'-/").___..--''"`-._
                 `Q_ Q  )   `-.  (     ).`-.__.`)
                 (_Y_.)'  ._   )  `._ `. ``-..-'
               _..`--'_..-_/  /--'_.' ,'
              (il),-''  (li),'  ((!.-'

Yuan Tingqiu  ytq@hwbji.co.cn Tel : +86 010 62561600 Fax: 68744460
Shenzhen Huawei Tech. Co.,Ltd.P.O.Box:2708-48 Beijing China(100080)

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>Cell Relay List Manager wrote:
> 
> regards,
> 
> Allen Robel
> cell-relay list janitor
> 
> From: "naveen rajanikantha" <rnavina@hotmail.com>
> To: comp.dcom.cell-relay@indiana.edu
> Subject: RE:Why CONNECT ACK does not EndpointRef ?
> Content-Type: text/plain
> Date: Fri, 25 Jul 1997 07:56:44 PDT
> 
> Hi,
> 
> >From my understanding, it seems to work fine with CONNECTACK(having no
> endpoint reference).
> Let us keep in mind that CALL REF is not end to end, it is unique in a
> UNI.
> The root connects to a Leaf through a NETWORK entity.
> 
> >  I have a question:
> >Under UNI4.0, Assume that the root sends a SETUP (1) to leaf 1,leaf 1
> >responded with the ALERTING, Now root sends an ADD PARTY(2) to leaf
> >2,but leaf 2 responds with the CONNECT even before leaf 1 can respond
> >with CONNECT .In this case the root will first receive a CONNECT (2).
> >that is to say,when network side receive a CONNECT(2), it will
> >response with CONNECT ACK ( having no EndPointReference),so user
> >(i.e,PBX switch) should remember (2) which send CONNECT.
> > if CONNECT ACK has EndpointReference,that will be okay?
> 
> Let me try to explain what is happenning,
> 
> 1. ROOT sends a SETUP to the switch (NETWORK UNI + Call control + ..)
>    orignating side, say the call ref is "X" and endpoint ref = 1
> 2. Call control asks NETWORK UNI to send a SETUP to the destination side
> (leaf) say the call ref is "Y". Only the call control knows that "X" and
> "Y" are the interconnected calls. UNI Network is going to handle it as
> two independent calls. The call control maintains a mapping between the
> interconnected call, the call ref's at the destination to the endpoint
> ref at the originating side.
> 3. Leaf(1) reponds with ALERTING("Y") and the call control maps this to
> ALERTING ("X" + endpoint ref "1") and asks UNI NETWORK to send it root.
> 4. Root sends ADDPARTY ("X" + "2"), the call control at the SWITCH
> (NETWORK UNI) maps this to second leaf and asks the UNI to send SETUP to
> the second leaf ("Z")
> UNI Handles originating and destination calls seperately.
> call control maintains a mapping, in this case it looks like
>              ORIGINATING                DESTINATION
>          CALL_REF, END_PT_REF       CALL_REF,  END_PT_REF
>              X           1             Y            1
>              X           2             Z            1
> 
> Depending on how the call control is implemented, the Destination maybe
> a POINT-TO-POINT call or a POINT-TO-MULTIPOINT call.
> 
> 5. Leaf 2 responds with a CONNECT("Z") the call control maps it to the
> originating side and asks the UNI to send a CONNECT with call ref "X"
> and end point "2". and sends a CONNECT ACK "Z" to leaf 2.
> The link state on the destination call ref "Z" goes to active state.
> 
> The party state of endpoint ref 2 will go to party active on sending the
> connect("X" + "2").
> 
> 6. The root receives the connect("X"+"2") and sends a CONNECT ACK ("X")
> to the NETWORK. On this side also party state of endpoint 2 becomes
> party active and also the link state with call ref X becomes active.
> 
> 7. The network on receipt of CONNECT ACK ("X"), changes the link state
> of call ref X to active.
> 
> 8. When leaf 1 responds with a CONNECT("Y"), the call control will ask
> UNI to send ADDPARTYACK("X" + "1") to root.
> 
> I don't see the need of having the end point reference in the CONNECT
> ACK message.
> 
> Hope this helps
> 
> Naveen R
> 
> ____________________________________________________________
> Unless otherwise stated, all these are my personal views
> - -------------------------------------------------------------
> 
> 
> 
> 
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> ------- End of Forwarded Message
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