Based on experience at iptel.org, we review current issues related to operation of SIP services on the public Internet. The issues include operational challenges such as NAT traversal, service reliability, scalability, and deployability. We show current practices and identify gaps that still need to be addressed by manafacturers.

Topics to be covered include:

• Status update: existing deployments, available services, interoperability
• Problem summary: NAT traversal, reliability, scalability, miscellaneous
• Operational practices
  • NAT: ALGs, manual configuration, UPnP, STUN, relay
  • reliability: use of DNS/SRV versus other solutions, replication mechanisms
  • deployability: scaling concerns, request routing in distributed networks, routing troubleshooting
• Conclusions: summary of current issues that still need to be addressed

About the Presenter
Jiri Kuthan is founder of iptel.org, a know-how organisation based in Berlin, Germany. Iptel runs a public SIP site and produces a free implementation of a high-performance SIP server. Jiri is responsible for planning the architecture of iptel.org's site and server.