MIME media types for DPNSS Objects in SIP {draft-mukundan-sipping-dpnss-02.txt : R Mukundan, V Seshasayee/ K Morneault/ R Shiroor/ N Mangalpally/ S Naganathan Wipro/ Cisco/ Sasken/ Nortel/ Hughes}

1
MIME media types for DPNSS Objects in
SIPdraft-mukundan-sipping-dpnss-02.txt R
Mukundan, V Seshasayee/ K Morneault/ R Shiroor/ N
Mangalpally/ S NaganathanWipro/ Cisco/ Sasken/
Nortel/ Hughes

• Ranjith Mukundan
• Wipro Technologies

2
What is DPNSS (in 30 secs)??

• DPNSS Digital Private Network Signaling
  System 1 Peer-to-peer (Symmetric),
  private-NNI protocol. Spec Oftels
  ND13012001/03 (previously BTNR 188)
• Industry standard for PBX inter-connection (or
  Centrex customers hosted off COs) Deployed in
  UK, NZ, Australia, India and parts of NA
  ISDN-like similar to QSIG (Europe/Germany)
• Approximately 250 suppl services (like Call
  Back When Free, Call Back When Next Used,
  Executive Intrusion, Travelling Class of Service,
  Do Not Disturb, Night Service, Private Network
  Route Optimization, Centralized Operator, Three
  Party Takeover, Remote Diversion Registration etc
  .).

Deployment Scenario 1 Basic
PBX
PBX
DPNSS
T1/E1
Deployment Scenario 2 VPN
ISUP (DPNSS tunnel)
CO
CO
PBX
PBX
PSTN
H.323 (DPNSS tunnel)
H323GW
H323GW
3
Is there a Need for DPNSS MIME in SIP??

• DUA is already past the WGLC on SIGTRAN. For
  inter-MGC scenarios we need DPNSS-MIME is SIP.
• Service Provider trials (e.g., H.323 to SIP
  migration in VPN/Enterprises that have DPNSS
  PBXs).
• As discussed on the list DPNSS is the only
  missing link (QSIG and ISUP MIME exist) so we are
  not opening a flood-gate.
• DPNSS?SIP translation is a complementary
  mechanism we are working on it NOT an
  alternative.
• Translation is required to complete calls along
  routes/nodes that supports only partial DPNSS
  service transparency.
• DPNSS MIME is required for complete service
  transparency would be almost impossible to map
  every detail of DPNSS to SIP (as is the case with
  ISUP and QSIG)

4
What is the (primary) difference between DPNSS
MIME and QSIG/ISUP MIME??

• Similar to RFC 3204 (MIME objects for ISUP/QSIG)
  i.e., same Content-Disposition Header etc..
• Mandates single binary coded octet message
  length field appended to the DPNSS PDU as the
  first byte.
• Specifies message Buffering Option (Detailed
  description of the usage examples).
• Mandates DPNSS ? SIP gateway to be modeled as a
  Transit PBX (Explained with an example).
• Mandates single DPNSS call per SIP dialogue.
• Specifies use of Version Parameter in DPNSS
  context.

5
Does the DPNSS Message Semantic Match with SIP??
DPNSS SIP
ISRM (Initial Service Req Msg) INVITE
NIM (Network Indication Msg) 100 TRYING
NAM (Number Ack Msg) 180 RINGING
CCM (Call Connected Msg) 200 OK
CRM (Clear Req Msg) BYE
CIM (Clear Indication Msg) 200 OK
EEM (End-to-End Msg) INFO

• Not an exhaustive list e.g., messages like
  Recall Message (RM) does not find a equivalent
  match (hence have to use SIP INFO Method)
• DPNSS Maintenance Messages are of local
  significance and hence need not be tunneled)

6
Conclusion

• Can be progressed as a WG I-D.
• Does not seem to be orthogonal to what SIPPING
  set out to do.
• Has been fairly (sufficiently?) discussed and
  reviewed on the list.
• Submit a DPNSS ? SIP translation I-D that
  complements the MIME I-D. (shall provide a Oftel
  and/or BTNR contact at that stage to assist in
  reviews)