1. Interworking between P2PSIP Overlays and IMS Networks: Why? How?
International SIP 2008
Interworking between P2PSIP Overlays and IMS Networks: Why? How?
Enrico Marocco and Gianni Canal
Telecom Italia Lab
{enrico.marocco,

2. Outline Real-time communications are changing Peer-to-peer SIP
Services vs. applications
What has been done so far?
What else can be done?
Peer-to-peer SIP
Why is it better than other technologies?
P2PSIP/IMS interworking scenarios
What is missing?
Conclusions

3. What's happening to real-time communications?
Telephony Service Providers
Exploit IP to build one access- agnostic service architecture
Legacy requirements
Easy deployment of new services
Enter the new (Internet) world
e.g IM, Chat, Second Life
Internet Companies
Enrich the web experience with new and low-cost real-time communications applications
e.g. GTalk, Yahoo!
Big success factor: cheap calls towards regular phones
e.g. Skype, SIPphone, Jajah

4. What can we do? Ignore Impede Leverage
We cannot compete in the “Internet” world
All in all, they push more bits in our pipes and pay us for call termination
Impede
Technically feasible
Saved earnings exceed loss due to unsatisfied subscribers
Leverage
Let our subscribers call their “net buddies”
Let third party applications access our telecom capabilities
e.g. identity, voic , payments, storage
Take care of the “interconnection” part
Provision of PSTN/PLMN interconnection requires big investments

5. What have we done so far? Branded VoIP+IM+telephone applications
Better than the originals
Connect with GTalk, Yahoo!, MSN [...] for free
Let make calls just as regular phones!
But users do not like them (YMMV)

6. The “Wengo” lesson One of the few Skype competitors
Open source application bound to Wengo SIP service
Free VoIP/IM, cheap calls/SMS
Worldwide community
Service ecosystem
Wengo is NEUF Telecom...
Direct connection with paying users
vs. skypeout earnings, split between Skype and local operators
... but users do not feel it
The operator can work as a back-end for communities
Contribute resources and sell services
Let the control to people

7. Dealing with people over the Internet
Approach established communities
Different technologies
Need agreements
Establish new communities
Significant investment
Extreme competition

8. Peer-to-peer SIP Hardware Bandwidth Fault Tolerance Configuration
INVITE
REGISTER
INVITE
REGISTER
INVITE
INVITE
INVITE
Fault Tolerance
Configuration
Management

9. P2PSIP: SIP for everyone
Good for Internet companies/communities
Build cheap solutions
Public service providers
Ad-hoc networks
Small scale IP-PBX
Connect with other networks
Good for Telecoms
Provide traditional services in other market segments
Calls between phones and web applications
Subscribers easily access their home network profiles
Free competition for service provision
e.g. interconnections, conferences, payments...
 peer-to-peer
 SIP
 SIP
 peer-to-peer

10. Calls between heterogeneous clients
telecomitalia.it
tel:
p2psip.org

11. Providing services to peer-to-peer clients
REGISTER sip:p2psip.org SIP/2.0
To:
From:
Contact:
telecomitalia.it
REGISTER sip:telecomitalia.it SIP/2.0
To:
From:
Contact:
p2psip.org

12. Gaps P2PSIP IMS Traffic relay in limited connectivity environments
Global reachability (DNS)
Service discovery
IMS
IPv4/IPv6 gateways
NAT traversal enabled on clients
SIM-less authentication
Peering policies

13. Conclusions Differentiation in real-time communications
“Services and applications” better than “services vs. applications”
“Offer” rather than “control” to succeed on the Internet
P2PSIP can enable IMS-friendly cheap communication services
P2PSIP overlays can be a marketplace for telecom operators
Topical issues to be addressed in IETF and 3GPP