Subject: RE: [SUA issues 3,6,7] text

From: [email-masked]
Date: Mon, 3 Sep 2001 15:49:54 +0530

John ,

You  can blame me for being stuck with a trivial issue , I still request ( once
again) for following clarifications in the text.

Best Regards,
-Sandeep

[email-masked] on 09/03/2001 03:50:38 PM

Please respond to [email-masked]

To:   "sigtran" <[email-masked]>
cc:   [email-masked] (bcc: Sandeep Mahajan/HSS)

Subject:  RE: [SUA issues 3,6,7] text

Hi all,

Here is my (final) proposal for these issues.  Please check if they
are sufficient.

John

3.10.1 SS7 Hop counter

   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 = 0x0101          |             Length = 8        |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                unused                         | SS7 Hop Count |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

SS7 Hop Counter (3.18/Q.713)

The value of the SS7 Hop Counter is decremented with each global title
translation and should be in the range 15 to 1.

Optional in CLDT, CLDR, CORE.

Sandeep >> I suggest the term "global title translation" be changed with "relay
node".

========================================================================

3.10.e Sequence Control

   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 = 0x010e         |             Length = 8         |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                               | Seq  Control  |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Sequence Control (1.1.2/Q.714)

The field is coded with the value of the sequence control parameter
associated with a group of messages and are chosen so as to ensure  proper
loadsharing of message groups over SLS values while ensuring that sequence
control values within message groups have the sequence control value coded
with the same value as the initial message of the message group.

Mandatory in CLDT, CORE, COAK, COIT.

Sandeep >> Above definition of sequence control is very encrypted and it is not
clear how SUA recommends this parameter to be used. As this parameter is used
for
a) Transporting "sequence control" parameter of N-UNITDATA request primitive
from SCCP/SUA user to SCCP in a backhaul case
b) Something similar to how SCCP uses SLS in RL of incoming SS7 message for
maintaining sequence of messages and loadsharing purposes in IPSP (peer to peer)
case

I suggest following text to start with

For Class 1
At originating SUA node, SUA user passes "sequence control" parameter to SUA in
N-UNITDATA request primitive. SUA use this parameter as input to AMF function
for SCTP asssociation and stream selection and copy the same in CLDT message.
While processing CLDT message (for protocol Class 1) at relay node , sequence
control parameter received in the CLDT
message SHOULD be used by AMF function for selecting next hop SCTP association
and stream. While processing CLDT message the terminating end SUA passes the
sequence control parameter received in CLDT message to SUA-USER using N-UNITDATA
indication primitive. Above procedure insures sequencing of class 1 messages
that are transferred either between IP and SS7 networks or within IP network.

For Class 0, 2 and 3
For these protocol classes SUA User does not pass sequence control parameter to
SUA. While processing N-CONNECT request, N-CONNECT response , and N-UNITDATA
request (protocol class 0) primitives , SUA based on some implementation
dependent loadsharing algorithm chooses a value of sequence control parameter.
This should be used as input to AMF for choosing next hop SCTP association and
stream and should be copied in CORE, COAK and CLDT (class 0) messages. At relay
node while processing these message SUA MAY use this sequence control value for
selecting next hop SCTP association and stream.
Note: There is no usage of this parameter for messages of these protocol class
transferred between IP to SS7 network, as for these protocol classes this
parameter can not be passed across IP and SS7 networks.

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