Subject: RE: [Sigtran] POINT CODES

From: Kasiraju Srinivasa Raju <[email-masked]>
Date: Fri, 24 Jan 2003 17:08:46 +0530

Hi,
thanks for the explainatory answer provided.
Could anyone help me for designing an ss7 overlay network with following
details/rules :
1.	Link load capability for A, B, C, D, E links for Sigtran and TDM
links.
2.	Since IP overhead is realtively high assuming LSL links of 64kbps
where is the point of Trade-off arriving between SCTP and TDM links.
3.	General Gateway screening rules for efficient network.
4.	Can the load-sharing capability of an STP overcome a network
element's in capability to do so.
5.	Global Title translation rules for efficient network.

::      Thanks and Regards,     :: 
        K.Srinivasa Raju, 
        Adv. Services,TTL- Hyd 
        Tatatel ] +91-40-55554064 
        Mobitel ] +91-40-56109064 
        email * [email-masked] 

-----Original Message-----
From: Coene Lode [mailto:[email-masked]]
Sent: Friday, January 24, 2003 4:20 PM
To: 'amit somani'; Sigtran
Subject: RE: [Sigtran] POINT CODES

> -----Original Message-----
> From: amit somani [mailto:[email-masked]]
> Sent: Friday, January 24, 2003 9:33 AM
> To: Sigtran
> Subject: [Sigtran] POINT CODES
> 
> 
> hello everyone!
> 
> i`m working on gtt i.e. global title translation.
> i could not understand the significance of PC-point
> code in calling & called party fields?
> can some one tell to which node these PC refer to?

I assume that you will do a GTT in the initiating endpoint. 

the pointcode in the Called party fields(=CLD) refers to the node which will
be a intermediate relay node(SRP) or the terminating endpoint node(SEP). 
the pointcode in the calling party fields(=CLG) refers to the node which
will be a intermediate relay node or the the initiating endpoint.
the pointcode in the CLG/CLD has the same significance as the OPC/DPC in the
MTP/M3UA routing label, they are only valid within that same network. 
The way in which the msg is routed is based on the routing indicator:
- route on GT: the msg may pass through intermediate SRP nodes(which will
yield different pointcodes for each translation)
- route on SSN: the msg is supposed to go directly to the final terminating
endpoint. It may pass SRP nodes but the GTT function must not be involved(as
it could possibly change Pointcodes AND the routing indicator). If invoking
GTT would happen then there is a strong possibility that the the response
msg going back would not be routable in the network.(none of us is
interested in blackholing traffic, I think)

> 
> if these r the PC to which the query message is to be
> sent then what is the significance of DPC-destination
> point code.
the DPC in the MTP routing label and the PC in the CLD should be the same
and the same is true for the OPC and the PC in the CLG.
it looks like redundant information but that is the way it is done. 
This way supports network architectures where the initiating endpoint does a
GTT which yield the final endpoint immediatly, so the endpoint can route
directly on PC alone(routing indicator set to route-on-SSN).(which should be
faster)
The drawback is that the msg cannot cross network borders. 

> 
> can someone plz lemme know what r the significances of
> various point codes.

Another network architecture  might be to put the GTT capability not in the
endpoint but distributed throughout the network and then the CLG and CLD
consists of a GT (PC may or may not be present). The DPC in the MTP routing
label could be the PC of the intermediate SCCP node doing GTT or the final
endpoint. The OPC would be the PC of the node which was the initiating
endnode or the node which did a intermediate GTT.
This methods allows for network border crossings and should be the one used
in all wireless networks.

> 
> also let me know whether called part field carries
> actually dialled number and calling party the phone
> number of the dialler?

Depends on the application:
- supplementary services such as CCBS: CLD = the dialled number, CLG= number
of the dialler
- wireless: mobility managment: CLD= dialled number, CLG= number of the
MSC/SGSN to which the subscriber is presently attached.
- wireless: MO-SMS( mobile origniating SMS): CLD= SMS service center number,
CLG = number of the MSC/SGSN to which the subscriber is presently attached.
- wireless: MT-SMS(mobile terminating SMS): CLD= number of the MSC/SGSN to
which the subscriber is presently attached, CLG = SMS service center number
....

as you can see there are a lot of possibilities...
> thank you.

Hope this helps...

yours sincerly,
Lode Coene

Siemens atea
atealaan 34          2200 Herentals, Belgium
E-mail: [email-masked]
Tel: +32-14-252081
Fax: +32-14-253212
 
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