Subject: [Sigtran] Adding more lines to M2UA and M3UA for TTC PRI bits

From: "Otsuka.Hiroshi" <[email-masked]>
Date: Thu, 31 Jan 2002 19:16:35 +0900

Dear Lyndon, Greg and Ken,

We (TTC) have been interested in adding some comments related 
to PRI on current M2UA and M3UA drafts, to make sure that the
everybody has the same idea for the location of PRI bits.   We think
people can understand how the PRI bits should be placed in M2UA
and M3UA from the drafts.   But we would like to add a few more 
comments in each drafts to give more clear understanding of PRI.
Since we asked to include the TTC spec. to M2UA and M3UA in 
2000, we believe it is our responsibility to give clear explanation to 
avoid any confusion.   So please consider to add following lines to 
current M2UA and M3UA drafts.

M2UA:
We would like to make sure the location of PRI bits in LI octet for
M2UA PDU.   I believe the LI octet appears twice in this draft (Section
3.3.1.1 Data and Section 3.3.1.11 Retrieval Indication).   We would like
to insert following lines after the sentence of "The Japanese TTC 
variant uses the spare bits of the LI octet for priority. "
in Section 3.3.1.1 Data (Page 19) of m2ua-13.txt.
----------------------------------------------------------------------------
-----------
The format of LI octet is;

    0               
    0 1 2 3 4 5 6 7 
   +-+-+-+-+-+-+-+-+
   |   spare   |PRI| (followed by SIO, SIF) 
   +-+-+-+-+-+-+-+-+
----------------------------------------------------------------------------
-----------

M3UA:
The existing MP explanation will be good enough to give understanding
of how the PRI bits are placed in MP field.   But we appreciate if 
following lines can be added after the sentences of MP description
(Page 31) of Section 3.3.1 Payload Data Message in m3ua-11.txt.
----------------------------------------------------------------------------
-----------
For example, the MP field for TTC-style would be;

    0 1 2 3 4 5 6 7 
   +-+-+-+-+-+-+-+-+
   |0 0 0 0 0 0|PRI| 
   +-+-+-+-+-+-+-+-+
----------------------------------------------------------------------------
-----------

Also we believe it will be nice to have following TTC document in the 
references of M2UA and M3UA, to provide the reference of PRI;
----------------------------------------------------------------------------
-----------
[x] Telecommunication Technology Committee (TTC) Standard JT-Q704,
    'Message Transfer Part Signaling Network Functions', 
    April 28, 1992.  
----------------------------------------------------------------------------
-----------

We believe these additional lines will not give any changes to the 
contents of M2UA and M3UA, but it will give more description of PRI
location.   We also believe it will be nice to have similar level of 
description among M2UA, M2PA and M3UA.

Again we appreciate if you consider to add above lines to these drafts.   
If you have any difficulties or comments, please let me know.

Best regards,
Hiroshi Otsuka

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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 31 Jan 2002 12:56:23 -0600

Otsuka,

A few comments below...

Otsuka.Hiroshi wrote:                              (Thu, 31 Jan 2002 19:16:35)
> in Section 3.3.1.1 Data (Page 19) of m2ua-13.txt.

Actually, I think that the LI octet (as present in the SS7 message)
looks like this:

      0
      0 1 2 3 4 5 6 7
     +-+-+-+-+-+-+-+-+
     |PRI|  ignored  |
     +-+-+-+-+-+-+-+-+

If the first byte of the message is not to be formatted the same
as it appears in the SS7 message, it should be separated into it's
own TLV parameter.

> (Page 31) of Section 3.3.1 Payload Data Message in m3ua-11.txt.

This is the same as for other protocol variants supporting message
priorities where the octet can take on the valies 0, 1, 2, 3.  IMHO
there is no need to separate out a TTC format here.

> references of M2UA and M3UA, to provide the reference of PRI;

I agree that it would be useful to add the reference.

--brian

-- 
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/