Cell Relay Archive

[Yu Ning <yuning@mindless.com>]

Let's better have a detail look at the Q.2931:

(from Q.2931)

5.1.2	Connection identifier (VPCI/VCI) allocation/selection - Origination
Two cases exist:
i)	associated signalling
The layer 3 signalling entity exclusively controls the VCs in the VPC which
carries its signalling VC.
ii)	non-associated signalling
The layer 3 signalling entity controls the VCs in the VPC which carries its
signalling VC and may control VCs in other VPCs.
The network and user shall support the non-associated signalling procedures
and may as an option support the associated signalling procedures. The
associated signalling procedures are used only by bilateral agreement between
the user and the network.
 When the network receives a connection identifier information element with
the VP-associated signalling field (see Table 4-16) coded with a value not
supported by the network, the call shall be rejected with cause No. 36,
"VPCI/VCI assignment failure".
5.1.2.1	Associated signalling
For associated signalling, the user requests a VC in the VPC carrying the
signalling VC. The VPC carrying the signalling VC is implicitly indicated.
In the Connection identifier information element, the VP-associated
signalling field is coded as "VP-associated signalling" and one of the
following values is indicated in the preferred/exclusive field:
a)	"exclusive VPCI; any VCI"; or
b)	"exclusive VPCI; exclusive VCI".
In case a), the network selects any available VCI within the VPC carrying the
signalling VC.
In case b), if the indicated VCI within the VPC carrying the signalling VC is
available, the network selects it for the call.
The selected VCI value is indicated in the Connection identifier information
element in the first message returned by the network in response to the SETUP
message (e.g. CALL  PROCEEDING message). The VP-associated signalling field
is coded as "VP-associated signalling". The preferred/exclusive field is
coded as "exclusive VPCI; exclusive VCI". 
In case a), if no VCI is available, a RELEASE  COMPLETE message with cause No.
45, "no VPCI/VCI available", is sent by the network.
In case b), if the indicated VCI is not available, a RELEASE  COMPLETE
message with the cause No. 35, "requested VPCI/VCI not available", is sent by
the network.
5.1.2.2	Non-associated signalling
In the user's request for a VC in the SETUP message, the user shall indicate
one of the following:
a)	"exclusive VPCI; any VCI";
b)	"exclusive VPCI; exclusive VCI"; or
c)	no indication is included (i.e. the Connection identifier information
element is not included in the SETUP message).
In cases a) and b), the VP-associated signalling field is coded as "explicit
indication of VPCI" in the Connection identifier information element.
In cases a) and b), if the indicated VPCI is available, the network selects
it for the call. In case a), the network selects any available VCI in the
VPCI. In case b), if the indicated VCI is available within the VPCI, the
network selects it for the call.
In case c), the network selects any available VPCI and VCI.
The selected VPCI/VCI value is indicated in the Connection identifier
information element in the first message returned by the network in response
to the SETUP message (e.g. CALL  PROCEEDING message). The VP-associated
signalling field is coded as "explicit indication of VPCI". The
preferred/exclusive field is coded as "exclusive VPCI; exclusive VCI".
In cases a) and b), if the specified VPCI is not available, a RELEASE 
COMPLETE message with cause No. 35, "requested VPCI/VCI not available", is
sent by the network.
In case a), if no VCI is available, a RELEASE  COMPLETE message with cause No.
45, "no VPCI/VCI available", is sent by the network.
In case b), if the VCI in the indicated VPCI is not available, a RELEASE 
COMPLETE message with cause No. 35, "requested VPCI/VCI not available", is
sent by the network.
In case c), if the network is not able to allocate a VCI in any VPCI, a
RELEASE  COMPLETE message with cause No. 45, "no VPCI/VCI available", is sent
by the network.
In case a), if the VPCI values in the first response message is not the VPCI
value indicated by the user, a RELEASE message with cause No. 36, "VPCI/VCI
assignment failure", shall be sent to the network.
 In case b), if the VPCI and VCI values in the first response message are not
the VPCI and VCI values indicated by the user, a RELEASE message with cause
No. 36, "VPCI/VCI assignment failure", shall be sent to the network.



Hope it will help.

Good Luck.


Yu Ning
>On Thu, 23 Jul 1998 15:27:09 -0700
>mukul@trillium.com (Mukul Katiyar) wrote:

>
>
>
>
>
>Mailer snapped part of the response, resending.
>
>> Hi Ronald,
>> 
>> If you are doing your signaling in some VPI (say 10) other than the
>> default VPI 0, then then data VCC should also be created in the same
>> VPI (10) in which signaling is done. This is called associated
>> signaling. 
>
>Associated signalling has nothing to do with the VPI of the signalling
>channel,
>Associated signalling is one, for which the signalling VC signals for all the
>VCs
>in the given VP only and for no other VC not present within the VP carrying
>the
>signalling VC. 
>
>You can have the signalling channel within the VP numbered VPI-10 and still
>perform
>the signalling for VCs beyond those within the VPI-10, or for a group of
>VPs, or even for all the VCs.
>
>
>
>> 
>> This associated signaling what you have asked, is not allowed in
>> UNI3.1 and UNI4.0. This is allowed only in PNNI Signaling right now.
>
>True Q.2931 and PNNI supports associated signalling.
>
>
>_______________________________________
>
>On Thu, 23 Jul 1998, Ronald Yap wrote:
>
>> Hi Folks,
>> 
>> I have a basic question on UNI3.1/UNI4.0...
>> 
>> If I create a PVP (vpi=10) and enable UNI signalling on that path, will all
>> subsiquent data-VCC created (via signalling) contained within the same PVP??
>
> The problem with this configuration is that at the access switch the VPC (
>irrespective 
> of SVPC or PVPC) shall be completely switched to the egress port, 
> not giving the signalling entity to look into the signalling messages
>flowing through the
> signalling channel within this VP. 
> 
> You shall not be able to signal for any VC within the VP far aside outside
>the VP that has been
> configured to PVP, with the standard implementation of signalling protocols. 
> Yes but an end to end signalling should be possible with the either ends
>understanding the 
> proprietry VP/VC assignments for each call, 
>
>> 
>> Is this specified in the standard documents? Or can the data-VCC be on
>> different PVPs?
>> 
>> Please advice...thanks.
>> /ronald
>> 
>------------- End Forwarded Message -------------
>
>

----------------------------------------------------------------------*
Yu Ning
ATM R&D Center
BUPT (Beijing U. of Posts&Telecom)
Beijing  (ZIP: 100876,  MBox: 147#),   P. R. China
BUPT: http://www.bupt.edu.cn
mailto:yuning@mindless.com or  yuning@263.net
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