1. Sridhar Ramachandran Chief Technology Officer sri@nextone.com Core Session Controller

2. NexTone Customers NexTone’s Session Controllers are deployed in over 100 carrier and service provider networks for a total capacity of over 2 BILLION minutes a month

3. What is a Session Controller? Point of control for multimedia signaling and media − Service protection − Network isolation and insulation Other names − IP-IP Gateway − Back to back gateway − Session Border Control − Border Session Control Point of control for multimedia signaling and media − Service protection − Network isolation and insulation Other names − IP-IP Gateway − Back to back gateway − Session Border Control − Border Session Control

4. Problems where VoIP has proven effective Transport Switching Interconnect − Carrier – Carrier − Enterprise – Carrier Applications Transport Switching Interconnect − Carrier – Carrier − Enterprise – Carrier Applications Top and bottom line enhancing Flexibility and enforceability are key Control points

5. Growth in VoIP Peering ITXC Carries Record Voice Call Volumes for Holidays http://www.itxc.com/pages/press/release229.html http://www.itxc.com/pages/press/release229.html “In past years, our carrier customers used ITXC to complete their subscribers’ calls because our VoIP technology allowed us to provide them high quality at low prices. Usually, the only VoIP involved was within our network. Now carriers also choose ITXC for interconnection because they themselves are deploying VoIP equipment in their own networks or even at their subscribers’ premises. Our technology allows these carriers to connect their VoIP networks to ours at much less cost than a legacy PSTN interconnect and with much greater flexibility.” In the fourth quarter of 2003, over one third of ITXC's traffic was originated or terminated through a direct VoIP interconnect between ITXC.net® and the network of another carrier. ITXC has VoIP interconnects with over 140 carriers or service providers in 60 countries and supports VoIP traffic exchange with a wide variety of network equipment vendor platforms based on either Session Initiation Protocol (SIP) or H.323 call control protocol. iBasis Posts Record VoIP Call Volume During New Year's Day http://www.ibasis.com/news/PR2004/pr01072004.htm "In addition to setting an overall record for traffic, we are experiencing a record volume of traffic that enters or exits the iBasis Network as IP traffic," said Ofer Gneezy, president and CEO of iBasis. "Major carriers have been deploying VoIP infrastructure to support both retail services and direct VoIP carrier interconnects. At the same time, new service providers are delivering VoIP services directly to residential and business consumers. Both can realize significant cost efficiencies by establishing direct VoIP interconnections with our proven global VoIP infrastructure. "More than 70% of iBasis traffic either originates or terminates through our direct VoIP interconnects with service providers. Direct VoIP interconnects require significantly less capital expense in the iBasis network than legacy TDM interconnects. In addition, we are enabling our customers to more fully benefit from the efficiencies of VoIP and the public Internet for global telecommunications."

6. VoIP Peering Requirements − Flexibility Media and Signaling Routing based on trust boundaries “Any-to-any” interworking – SIP, H.323, multiple vendor interoperability High Performance and Scale “On-demand” Media Processing − Leverage and enforce existing peering agreements Call Admission Control  Prevent Denial of Service attacks and service abuse/theft Call accounting  Call Detail Record (CDR) generation and reporting Topology Hiding  Go across address boundaries − Control Points Segmentation/classification of traffic

7. What are Carriers’ session control needs? Call routing with multiple business models: − Wholesale − Transit − Pre-paid − Post-paid/retail Service brokerage Special applications − Permissive dialing Call routing with multiple business models: − Wholesale − Transit − Pre-paid − Post-paid/retail Service brokerage Special applications − Permissive dialing

8. Edge SC Session Controller Placement SIP Network Enterprise Peering PSTN Broadband H.323 Network Carrier Peering Broadband NAT Traversal PSTN Orig/Term Edge SC Softswitch Core SC Edge SC

9. Aggregation Multiple interconnects between same carriers Multi-stage and hierarchical call admission control Core SC maintains notion of aggregate capacity Multiple interconnects between same carriers Multi-stage and hierarchical call admission control Core SC maintains notion of aggregate capacity Partner Carrier IP Network Carrier IP Network Edge SC Core SC Edge SC

10. Merits of this Approach No “control” protocol Call admission control based on network egress policies Ability to add other service selection logic − Applications − Quality of Service demanded or provisioned Call routing with mixed business models − Wholesale − Pre-paid or post-paid − Transit Normalized and vendor independent call routing − SIP only No “control” protocol Call admission control based on network egress policies Ability to add other service selection logic − Applications − Quality of Service demanded or provisioned Call routing with mixed business models − Wholesale − Pre-paid or post-paid − Transit Normalized and vendor independent call routing − SIP only

11. Other Advantages Implementation flexibility − Redirect server − Stateful SIP proxy − B2BUA Core SC function can be integrated into Edge SC Leverage TRIP (rfc 3219) and TGREP View Edge SCs and Gateways as originators and terminators of sessions Implementation flexibility − Redirect server − Stateful SIP proxy − B2BUA Core SC function can be integrated into Edge SC Leverage TRIP (rfc 3219) and TGREP View Edge SCs and Gateways as originators and terminators of sessions

12. What about the “Softswitch”? “Control” paradigm has limited effectiveness − Gateway control − Call control Softswitch designed for a “closed” network − MGCP/MEGACO to provide total control of internal network How does one build a fabric of softswitches? “Control” paradigm has limited effectiveness − Gateway control − Call control Softswitch designed for a “closed” network − MGCP/MEGACO to provide total control of internal network How does one build a fabric of softswitches?

13. Summary Session Controllers are essential for VoIP peering Core Session Controllers provide higher level functionality, based on SIP signaling Session Controllers are essential for VoIP peering Core Session Controllers provide higher level functionality, based on SIP signaling

14. Thank You. sri@nextone.comsri@nextone.com ; +1-240-912-1301

15. What about the “Softswitch”? “Control” paradigm has not proven effective Softswitch designed for a “closed” network − MGCP/MEGACO to provide total control of internal network VoIP interconnects challenge the Softswitch “control” paradigm − Interconnects = carrier peering, and MGCP/MEGACO “control” of 3 rd party networks not viable − SIP/H323 typically added as after-thought to interwork trusted devices Softswitch domains (and VoIP interconnects should never be trusted) VoIP Interconnect Solution: − Keep SS7 and MGs at the edge of the VoIP network, Softswitch as “cluster controller” to help handle SS7/C7 − Introduce Session Controllers to manage VoIP peering and interconnects between carriers and enterprises − Overcome lower layer (Layer 2/3) IP issues call-by-call – NAT/PAT, security, VLANs etc “Control” paradigm has not proven effective Softswitch designed for a “closed” network − MGCP/MEGACO to provide total control of internal network VoIP interconnects challenge the Softswitch “control” paradigm − Interconnects = carrier peering, and MGCP/MEGACO “control” of 3 rd party networks not viable − SIP/H323 typically added as after-thought to interwork trusted devices Softswitch domains (and VoIP interconnects should never be trusted) VoIP Interconnect Solution: − Keep SS7 and MGs at the edge of the VoIP network, Softswitch as “cluster controller” to help handle SS7/C7 − Introduce Session Controllers to manage VoIP peering and interconnects between carriers and enterprises − Overcome lower layer (Layer 2/3) IP issues call-by-call – NAT/PAT, security, VLANs etc

16. Core Session Controller Introduction What is a session controller? Growth in VoIP peering Need for more control at the core View of softswitch Core session controller fabric Introduction What is a session controller? Growth in VoIP peering Need for more control at the core View of softswitch Core session controller fabric