Subject: Fwd: Re: [Sigtran] Ali again " Brain please check this for M2PA

From: ali ovaisi <[email-masked]>
Date: Wed, 11 Jul 2007 10:27:26 -0700 (PDT)

Note: forwarded message attached.
 
---------------------------------
We won't tell. Get more on shows you hate to love
(and love to hate): Yahoo! TV's Guilty Pleasures list.

Subject: Re: [Sigtran] Ali again " Brain please check this for M2PA
From: ali ovaisi <[email-masked]>
To: [email-masked]
Date: Wed, 11 Jul 2007 05:20:32 -0700 (PDT)

dear Brian
   
  i am sending this summary, please have a look at it.
  and you have said about data chunk header in last email plz tell whether by this u mean the M2PA, M3UA, M2UA headers or some other headers. and also u have written that i am missing "possibly Ethernet or IEEE 802.something header"
  where and why?
   
  KR
   
  ali

  For M2PA
   
  If we take average message length as 40 octet for an ISUP message than 
  After reaching the SG (signalling gateway), SIGTRAN’S M2PA encapsulated the SS7 message data and attached headers in it.
   
  The headers are of 2 type’s “Common message header” and “M2PA header” in M2PA.
  The common message header is of 8 bytes and M2PA header is also of 8 bytes. 
   
  The User data or SS7 ‘Message data’ is the data from MTP3. so it don’t contains ‘flag 1 byte’, ‘BSN and BIB 1 byte’, ‘FSN and FIF 1 byte’, ‘Length indicator 1 byte’, and ‘ check sum 2 bytes’. Which all together make 6 bytes. After subtracting 6 bytes from average message length of 40 bytes we get 34 bytes.
   
   So estimated value, after adding M2PA header will be 40 bytes (ISUP) - 6 bytes (FSN/BSN not included) + 16 bytes (M2PA HEADER) = 50 bytes  (where I have to further add IP and SCTP header in it as well). 

  For M3UA
   
  In m3ua it add similar 8 byte common header as in m2pa. And there is no m3ua header in it.
   
  Common header         Mandatory       8 bytes (ver, reserved, msg class, msg type, length)
   
  As there are 6 message types in M3UA, but the only message type I am concern for SS7oIP rate is of the Transfer Messages, which contains payload data (which contains the SS7 MTP3-User protocol data).
  Payload Data Message contains
   
  1 Network appearance                        Optional                       8 bytes (tag, length, value)
  2 Routing context                                Conditional                  8 bytes (tag, length, value)
  3 Protocol data (MTP3 PDU)              Mandatory                   4 bytes for (tag, length)
                                                              +         12bytes for (OPC, DPC, SI, NI, MP, SLS)
                                                              =          16 bytes plus (MTP3 user protocol data)
   
  4 Correlation id                                    Conditional                  8 bytes (tag, length, value)

  So for M2UA, it adds header of 8+4+12= 24 bytes with the protocol data (MTP3 data)
   
  If we take average message length as 40 octet for an ISUP message and since The User data or SS7 ‘Message data’ is the data from MTP3 user, so it don’t contains ‘flag 1 byte’, ‘BSN and BIB 1 byte’, ‘FSN and FIF 1 byte’, ‘Length indicator 1 byte’, and ‘ check sum 2 bytes’. Which all together make 6 bytes)
   
  So estimated value after adding M3uA header will be 40 bytes (ISUP) - 6 bytes (FSN/BSN not included) + 24bytes (M3UA HEADER) = 58 bytes  (where I have to further add IP and SCTP header in it as well). 

   
  Q1 Network Appearance is Optional so whether we add it normally in our estimation or not and why?
   
  Q2 Routing Context is Conditional so whether we take this or not and why?
   
  Q3 Correlation id is also conditional whether we take this or not and why?

  And please also tell the RFC number for SCTP and IP.  
   
  M2UA
   
  In M2UA it add similar 8 byte common header as in M2PA.
   
  1 Common header      Mandatory       8 bytes (ver, reserved, msg class, msg type, length)
   
  MUPA contains the M2UA message header which is of 8 bytes
   
  2 M2UA message header       Mandatory (for MAUP only)       8 bytes (tag, length, 
                                                                                                  Interface Identifier (integer))
   
  As there are 5 message types in M2UA, but the only message type I am concern for SS7oIP rate is of the MUAP, which contains payload data (which contains the SS7 MTP2-User protocol data).
   
  3 Pay load data messages contain: 
   
  1 Protocol Data (MTP2 user data)      Mandatory       4 bytes (tag, length)
                                                                                      Plus protocol data (MTP3 data)      
   
  2 Correlation Id                                    Optional           8 bytes (tag, length, value)

  So for M2UA, it adds header of 8+8+4= 20 bytes with the protocol data (MTP3 data)
   
  If we take average message length as 40 octet for an ISUP message and since The User data or SS7 ‘Message data’ is the data from MTP3, so it don’t contains ‘flag 1 byte’, ‘BSN and BIB 1 byte’, ‘FSN and FIF 1 byte’, ‘Length indicator 1 byte’, and ‘ check sum 2 bytes’. Which all together make 6 bytes)
   
  So estimated value after adding M2PA header will be 40 bytes (ISUP) -6 bytes (FSN/BSN not included) +20bytes (M2PA header) = 54 bytes (where I have to further add IP and SCTP header in it as well). 
   
  Q1 Correlation id is also conditional whether we take this or not and why?

"Brian F. G. Bidulock" <[email-masked]> wrote:  ali,

> 
> "If we take average message length as 40 octet for an ISUP message
> than
> 
> After reaching the SG (signalling gateway), SIGTRANS M2PA encapsulated
> the SS7 message data and attached headers in it.
> 
> The headers are of 2 types Common message header and M2PA header.

You are missing the DATA chunk header, SCTP packet header, IP packet header
and possibly Ethernet or IEEE 802.something header.

--brian

> 
> The common message header is of 8 bytes and M2PA header is also of 8
> bytes.
> 
> The User data or SS7 Message data is the data from MTP3. so it dont
> contains flag 1 byte, BSN and BIB 1 byte, FSN and FIF 1 byte, Length
> indicator 1 byte, and check sum 2 bytes. Which all together make 6
> bytes. After subtracting 6 bytes from average message length of 40
> bytes we get 34 bytes.
> 
> 
> So SS7oIP for M2PA generates 34+16 bytes = 50 bytes of data per ISUP
> message.
> 
> As there are 5 messages in typical ISUP call so 50 * 5= 250 bytes of
> SS7oIP data is generated per ISUP call."
> 

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

---------------------------------
Bored stiff? Loosen up...
Download and play hundreds of games for free on Yahoo! Games.

_______________________________________________
Sigtran mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/sigtran