1. IP Telephony Accounting and WAN Deployment Experience Sven Ubik ubik@cesnet.cz

2. CESNET A not-for-profit organization for development and operation of Czech NREN 2.5 Gb/s backbone (CESNET2 network) Member of Géant and TERENA Partner of Internet2 Gigabit network testing laboratory

3. Project goals Interconnect PBXs of largest universities on CESNET2 network Create VoIP testbed (e.g., for QoS for VoIP tests on a real WAN network) Reduce cost of telephone calls between interconnected universities and to PSTN Develop means for statistical measurement of VoIP traffic allowing optimization of PSTN / mobile phone gateway locations Phase 2: QoS tests, IVR applications

4. Pilot project

5. Current VoIP network

6. 16000 users 11 voice gateways (Cisco) 9 PBXs (Erricson, Siemens, Alcatel, Matra) PSTN / mobile phone network gateway Connection to CERN, Switzerland (Bremen and Hannover, Germany) Mostly H.323

7. Statistical measurement - features Flexible accounting plans and using multiple accounting plans in parallel Output at different levels of aggregation Modular architecture - using multiple protocols for gathering call data Based on open software Resilience against network configuration changes Recovery from broken and lost call data

8. Statistical measurement - design 3 layers: Call data gathering (e.g., RADIUS, syslog) Data processing Presentation Where to account calls?

9. Statistical measurement - architecture Linux MySQL database LDAP authorization

10. Call legs

11. Using RADIUS messages Predefined set of attributes (RFC2865, RFC2866) does not contain some important information (e.g., start and end time of a session) 2 solutions: Vendor-specific attributes Overloading of AcctSessionId attribute

12. Using RADIUS messages (cont.) Vendor-specific attributes h323-gw-id=AS2-OV.ten.cz h323-conf-id=4776D8CD B9A60177 0 37DBD1 74 h323-call-origin=answer h323-call-type=VoIP h323-connect-time=16:17:16.256 MET Mon Jan 22 2001 h323-disconnect-time=16:17:16.256 MET Mon Jan 22 2001 h323-disconnect-cause=10 h323-remote-address=195.113.134.240 427/10:08:23.785 MET Thu Nov 23 2000/Voice-OV.ten.cz/ 9662886D A66029F 042FD97B4/answer/Telephony/ 10:08:54.544 MET Thu Nov 23 2000/10:08:57.194 MET Thu Nov 23 2000/10/195.113.134.240 Overloading AcctSessionId attribute

13. Caching legs Unneeded legs (may be needed later) Broken legs (may be replaced by other legs)

14. Statistical measurement - summary Using multiple accounting plans in parallel Recovery from broken and lost call data Output at different levels of aggregation Based on open software

15. Specification of accounting parameters

16. Example listing

17. Online trial Try at: https://ipta.ten.cz/test Register for username/password at: https://ipta.ten.cz/register Contact information http://www.cesnet.cz/english/project/iptelephony ubik@cesnet.cz