1、 TECHNICAL REPORT ATIS-0500028 Analysis of Unwanted User Service Interactions with NG9-1-1 Capabilities As a leading technology and solutions development organization, the Alliance for Telecommunications Industry Solutions (ATIS) brings together the top global ICT companies to advance the industrys
2、most pressing business priorities. ATIS nearly 200 member companies are currently working to address the All-IP transition, network functions virtualization, big data analytics, cloud services, device solutions, emergency services, M2M, cyber security, network evolution, quality of service, billing
3、support, operations, and much more. These priorities follow a fast-track development lifecycle from design and innovation through standards, specifications, requirements, business use cases, software toolkits, open source solutions, and interoperability testing. ATIS is accredited by the American Na
4、tional Standards Institute (ANSI). The organization is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a founding Partner of the oneM2M global initiative, a member of and major U.S. contributor to the International Telecommunication Union (ITU), as well a
5、s a member of the Inter-American Telecommunication Commission (CITEL). For more information, visit www.atis.org. Notice of Disclaimer Service principles4Ref 104: 3GPP TS 22.173 IP Multimedia Core Network Subsystem (IMS) Multimedia Telephony Service and supplementary services; Stage 1 Ref 105: 3GPP T
6、S 24.229 IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 1This document is available from the National Emergency Number Association (NENA). 2This document is available from the National Institute of Standards and Technolo
7、gy (NIST). . 3This document is available from the Alliance for Telecommunications Industry Solutions (ATIS), 1200 G Street N.W., Suite 500, Washington, DC 20005. 4This document is available from the Third Generation Partnership Project (3GPP) at . ATIS-0500028 2 3 Definitions, Acronyms, there is no
8、coverage of equivalent capabilities for other forms of communication such as IM. b) Some supplementary services can be implemented in the SIP client in the UE rather than the legacy CS presumption that all supplementary services are implemented in the network. Hence the network may not have knowledg
9、e of some service interactions. c) Devices will have different levels and forms of support for simultaneous IP communication services. For example one device could support video PIP and another device may not support it. d) Different types of multi-media have different levels of user cognitive abili
10、ties to support or deal with multiple simultaneous disparate sessions (“multi-tasking” abilities). For example, users have limited abilities to handle multiple simultaneous audio conversations whereas users often will be engaged in multiple IM sessions with different social contacts at the same time
11、. 5.6 Emergency SIP registration in RATs with emergency bearers Short Descriptions 3GPP TS 24.229 specifies SIP emergency registration procedures when the Radio Access Technology (RAT) supports emergency bearer procedures. However these emergency registration procedures are based on a single voice e
12、mergency service, using a single public user identity. This limits the ability to support multi-media emergency communication. Actors Oklahoma Mobile a wireless network operator. Curly McLain a user of Oklahoma Mobile. Will Parker the PSAP call taker in the PSAP with jurisdiction over the political
13、area Curly McLain is present in. Normal Pre-Conditions Curly McLain has two public user identities his MSISDN of 555-555-1212 and Curly.McL. Normal Post-Conditions Multi-media emergency communication may not work correctly with multiple user identities. Will Parker may not be able to initiate emerge
14、ncy callbacks even though Curly McLains UE is active and has sufficient radio signal conditions to communicate. Normal Flow 1. Curly McLain sees a tornado forming and decides to alert the authorities. 2. Curly McLain initiates a 911 voice call. 3. The UE requests an emergency bearer and initiates an
15、 emergency registration with his MSISDN 555-555-1212. 4. The UE then initiates the voice emergency call using the MSISDN registration. 5. The noise of the tornado becomes too loud and Curly McLain decides to switch to IM session. 6. Curly McLain initiates an IM session to 911. 7. The UE initiates a
16、new emergency registration using the Curly.McL public user identity. 8. The Oklahoma Mobile SIP registry deletes the 555-555-1212 emergency registration and registers Curly.McL as the emergency registration. 9. Curly McLain disconnects the emergency voice session, but maintains the IM session. 10. W
17、ill Parker decides it is important to continue the voice communication and initiates a callback to Curly McLains MSISDN. 11. Since the MSISDN is not registered, the Oklahoma Mobile call processing system sends the call back to voice mail handling. ATIS-0500028 10 Impact Considerations The procedures
18、 in 3GPP TS 24.229 appear to be based on the assumption that only one user identity would be active at a time during emergency communication (probably voice only) and this seems to limit having multiple user identities being used for multi-media emergency service. This is used at least for call back
19、 purposes and routing the signaling and media properly through the emergency bearers. So the following aspects at a minimum should be reviewed in terms of using multiple identities simultaneously for multi-media emergency services (MMES) (there may be additional aspects to consider as well): a) The
20、requirement of using the first public user identity in the ISIM or equivalent for the emergency registration. b) Only allowing one public user identity at a time for the emergency registration. c) Assuming that the previous emergency public user identity registration to be expired when a new emergen
21、cy public user identity is registered. 5.7 Emergency Callback Blocked by Whitelists or Privacy Settings Short Descriptions Many internet messaging services provide the ability to maintain a Personal Network Whitelist (PNW) of the only identities which are allowed from to contact the user. Others hav
22、e privacy settings that only allow specific social network connections or classes of social network connections (like family) to contact the user. Actors Pitcairn PCS a wireless network operator. William Bligh a user of Pitcairn PCS who is on a ship which has foundered on a rocky coast. Fletcher Chr
23、istian the PSAP call taker who is selected by the PSAPs network elements to receive William Blighs emergency communication. Pre-Conditions Pitcairn PCS supports Rich Communication Services (RCS) 5.1 and has separate CPM, file store, and voice servers operating as Application Servers (AS) in their IM
24、S network. William Bligh is subscribed to voice, the one-to-one instant message, and file delivery services of Pitcairn PCS and has a smartphone with a camera and an embedded RCS 5.1 client. His IM public user identity is BountyPitcairnPCS.net. His privacy settings only allow those in his social net
25、work connections to contact him through IM those are the senior officers on the ship. Post-Conditions William Blighs interrupted emergency communication cant be re-established to complete Fletcher Christians gathering of the foundering details. Normal Flow 1. William Bligh is on a ship which founder
26、s on a jagged headland on a coast. He decides to communicate with emergency services through IM. 2. William Blighs UE establishes communication with Fletcher Christian using the identity bountypitcairnPCS.net and a few details of the foundering ship are communicated. 3. Radio conditions deteriorate
27、temporarily and the emergency session is disconnected. 4. Radio conditions improve to a level where William Blighs UE reattaches to the Pitcairn PCS network. 5. Fletcher Christian attempts to re-establish an IM session with William Bligh using the identity from the initial emergency communication se
28、ssion bountypitcairnPCS.net. 6. The Pitcairn PCS IM service recognizes that Fletcher Christians identity is not one of William Blighs social network connections and due to William Blighs privacy setting and rejects the request to establish a callback emergency communication session. ATIS-0500028 11
29、Impact Considerations It may be desirable to merely indicate that any “callback” with an emergency service indicator by-pass the personal network whitelist or any privacy settings. However there are several considerations which add complications to the issue and require further study: a) There is no
30、 consistency for the originators identity presented on an emergency “callback” among the PSAPs. If we assume without any form of consistency, not only could the PSAPs have their own individual identity, they may also have different identities based on the specific communication service. So for examp
31、le a PSAP could have its main non-emergency phone number as the caller for voice services, it could also have Plainville_emergency_serviceplainville.state.gov as its IM identity. Further, some PSAPs could also have a separate identity for each call taker such as their first name, so another possibil
32、ity is john_plainville_emergency_serviceplainville.state.gov. The result is that there could be close to 20,000 identities for PSAPs that would have to be checked in a global override of PNW and privacy setting database, and if call taker identities were used as well, there could be well over 100,00
33、0 identities with frequent changes due to PSAP staffing turnover that would need to be verified in a global override of PNW and privacy setting database. b) The use of an emergency service indicator in a callback to by-pass the PNW and privacy settings can open up an easily exploitable opportunity f
34、or fraud and spoofing for normal communication to bypass the PNW and privacy settings unless the use of the emergency service callback indicator incorporated an authorization and authentication mechanism. 5.8 Users Multiple Devices Linked through Globally Routable UA URI (GRUU) Short Descriptions A
35、user is able to have multiple UEs and through GRUU they all share the same public user identity. SIP/IMS provides a capability to signal all the users devices or distinguish specific devices when appropriate. Actors TransNet a wireless network operator. Janet Weiss a user of TransNet who has is expe
36、riencing dropsy. Brad Majors the PSAP call taker who is selected by the PSAPs network elements to receive Janet Weiss emergency communication. Pre-Conditions Janet Weiss has two mobile devices one a smartphone and the other a high resolution wireless camera. Both are associated with her subscription
37、 under the public user identity of RHPS. The camera does not support any voice or text messaging services. Post-Conditions Brad Majors IM communication during the emergency communication may not reach Janet Weiss and callbacks may fail to reach Janet Weiss as well. Normal Flow 1. Janet Weiss dropsy
38、condition flares up and she decides to IM 911. 2. Janet Weiss, on her smartphone establishes an emergency IM session with Brad Majors using her identity RHPS. 3. TransN adds the smartphone instance to the session invitation. 4. Janet Weiss takes a picture on her camera of the dropsy affliction and s
39、ends it to 911 using her identity RHPS as well as asking “does this look bad?” in the IM session. 5. TransN adds the camera instance to the photo transfer session invitation. 6. Brad Majors PSAP infrastructure is able to associate the two sessions (IM and photo) based on the same user identity, howe
40、ver the PSAP infrastructure does not support GRUU and only retains the latest user identity and instance that it received (from the camera). 7. Brad Majors next IM message is sent to Janet Weiss camera instance (last identity stored) rather than to the smartphone. ATIS-0500028 12 8. Janet Weiss came
41、ra does not support IM messaging and hence ignores Brad Majors IM messages. 9. Radio conditions deteriorate temporarily and any emergency sessions to Janet Weisss devices are disconnected. 10. Radio conditions improve to a level where both of Janet Weiss UEs reattach to the network. 11. Brad Major i
42、nitiates an IM callback to Janet Weiss. However since the PSAP infrastructure uses the last known identity, this identity includes her cameras instance. 12. Janet Weiss camera receives an emergency IM session establishment request but does not support IM services and rejects or refuses the request.
43、Impact Considerations PSAP and NG9-1-1 networks will need to support GRUU and utilize the capability appropriate to specific scenarios and policies. It may be worthwhile to standardize some level of appropriate support and policy on addressing GRUU in PSAP and NG9-1-1 infrastructure. 5.9 Multiple Us
44、ers Sharing a Single GRUU Public User Identity Short Descriptions Multiple users are able to share the same public user identity through the use of GRUU. SIP/IMS provides a capability to signal all the users registered for the public user identity or distinguish specific users when appropriate. Acto
45、rs Big Apple Zone a wireless network operator. Peter Venkman a user of TransNet. Raymond Stantz a user of TransNet. Egon Spengler a user of TransnNet. Dana Barrett the PSAP call taker who is selected by the PSAPs network elements to receive Peter Venkman emergency communication. Pre-Conditions Peter
46、 Venkman, Raymond Stantz, and Egon Spengler share a public user identity related to their business . The PSAP does not support GRUU instance identifiers. Normal Flow Post-Conditions Dana Barretts IM communication during the emergency communication may reach the wrong person and an emergency callback
47、 may be answered by the wrong person. Normal Flow 1. Peter Venkman witnesses a criminal activity - talking in a library and decides to IM 911. 2. Peter Venkman, on his smartphone establishes an emergency IM session with Dana Barrett using his public identity . 3. Big Apple Net adds the smartphone in
48、stance to the session invitation. 4. Dana Barretts PSAP does not support GRUU instance identifier and drops them from subsequent signaling. 5. When Dana Barrett sends a text message to Peter Venkman, some are received instead by Raymond Stantz and some received by Egon Spengler. 6. Radio conditions deteriorate temporarily and any emergency sessions to Peter Venkmans UE are disconnected. 7. Radio conditions improve to a level where Peter Venkmans UE reattaches to the network. 8. Dana Barrett initiates an IM callback to without an instance identifier. 9. All three users registered fo
