Barriers to Enum What VoIP providers ask about Enum Dr. Dorgham Sisalem

1. Barriers to EnumWhat VoIP providers ask about EnumDr. Dorgham Sisalem

2. Scope • Peering: why bother • Current status of VoIP peering • What VoIP providers ask for • Open questions about Enum!!

3. Status AVM Box AVM Box AVM Box

4. Why Bother • VoIP works, is cheap and is nearly stable so why Bother about peering, Enum ….? • Each VoIP service is a separate island • Suboptimal routing -> Interconnection Costs over PSTN • Number portability • Will be a requirement when VoIP becomes first line • Solution should support providers with „rented“ E.164 number ranges

5. Current Practices: PSTN Interconnect AVM Box AVM Box AVM Box • Connect over PSTN • Inefficient routing • Higher costs • Possible lower QoS • Services restricted to common denominator • LNP • Use current LNP database • No support for rented numbers • Need to couple IP devices with legacy infrastructure

6. Current Practices: Direct Interconnect AVM Box AVM Box AVM Box • Inter-provider agreements • All numbers with prefix X are routed to provider Y • Exchange E.164 number ranges • Administration overhead is a nightmare • LNP nearly impossible • High level of trust and cooperation between competing providers

7. Current Practices: Private Number Exchange AVM Box AVM Box AVM Box • Efforts lead by certain providers to allow exchange of numbers • No wide acceptance • No clear funding and support structure • No clear technical evaluation • Scalability • Privacy and security NEX

8. What are VoIP providers looking for • An entity that provides the technological infrastructure for supporting • Number routing • LNP • This entity must be • A service provider for VoIP providers • Politically independent • Technologically capable • Based on LNP/MNP Experience • Central Database for consistency • Distributed caches for performance • Open interfaces • Announce number ranges • Announce ported numbers • Specify provider specific rules

9. Proposed Solution AVM Box AVM Box AVM Box Central DB

10. ENUM AVM Box AVM Box AVM Box • The magic cure for everything? • Technology is rather understood but still many open questions ENUM

11. ENUM: VoIP providers • Control: Who is running the infrastructure? • Do the providers have a say on • how the system should look like? • How much things should cost? • What the interfaces should look like? • Providers in Germany are looking at industry organizations for playing this rule • Privacy: Who sets the policy? • Can the providers set their own privacy and number transparency policies? • Show my numbers to provider A but not to provider B?

12. ENUM: Technology • Scalability: ENUM is NOT as scalable as DNS • Caching is useless • Would be similar to have a mail server to cache email addresses • Transport: NAPTR records can very easily exceed the UDP size • Fragmentation problems • Bandwidth load on the central ENUM server • Performance • Measurements suggest query times between 500 msec and 2500 msec • LNP and Delegation: With delegation only complete number ranges are delegated to another server • With LNP some central server will need to maintain all the numbers

13. ENUM: Privacy • Some privacy advocates claim: • Anonymity is no longer supported • To be reached one has to publish the phone number • Too much information about the users in a central location • Could be misused by governments

14. ENUM: Conclusion • To successfully sell the technology one should concentrate less on technology and provisioning interfaces and more on • Address concerns of VoIP providers and privacy advocates • Conduct large scale performance tests taking into account: • Scalability • Answer times with complex NAPTR records • LNP • The results of such tests and answers should be easily accessible