RE: SUA: Data limitation based on SS7 SCCP specification.

It depends whether you are going to use SUA only in the IPSP
configuration or will be interworking with SS7 networks through a
signalling gateway. If you intend to pass through a gateway, you have to
be sensitive to the characteristics of the gateway, the network on the
other side, and the destination signalling point.

The network will have a limit on the size of a message, most likely the
traditional SS7 payload size of around 256 octets (less than that for
data in an SCCP message). So if there is no message segmentation, the
originating SP has to hold to that.

Segmentation requires support at the originating ASP or signalling
gateway and at the destination point (and the support should be assumed
to be absent unless known to be otherwise). 

Stewart Patch
Engineering
NewStep Networks Inc.
+1 416 979 5404 x485
 

-----Original Message-----
From: Sulakshan Vajipayajula [mailto:[email protected]] 
Sent: 23 October 2007 10:58
To: [email protected]
Subject: [Sigtran] SUA: Data limitation based on SS7 SCCP specification.

Hi all,

I have a question pertaining to limiting the data size in SUA connection
oriented messages such as CORE or RELRE. 

The RFC says the following.  My question is, if the implementation
should follow SS7 SCCP specification in limiting the data size or should
it allow the data size based on the section 3.10.11.  The SCCP spec
limits the data to 128 octets. Does this apply to SUA as well?

RFC 3868                          SUA                       October 2004


3.10.11.  Data

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Tag = 0x010b         |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   /                             Data                              /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Data parameter field contains the SS7 SCCP-User application
   Message, for example an INAP/TCAP message.



SCCP Specification:
-------------------
Parameter Reference Type (F V O) Length (octets)
--------------------------------------------------
Data  |     3.16   |      O   |        3-130


Thank you
Sulakshan



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