1. Intradomain gateway discovery requirements Henning Schulzrinne Columbia University

2. 6/26/2015 52 st IETF Organizational assumptions Possibly “mutual aid” e.g., gateway calls to local calling area without billing Loosely affiliated, with different administrators different university campuses different branches of enterprise

3. 6/26/2015 52 st IETF Example P G P G P G P G 415 212 UCB Columbia U.

4. 6/26/2015 52 st IETF Dynamic configuration New gateways or gateway capacity capacity changes For university networks (e.g., I2), potentially several hundred participants Policy changes new area codes adds additional calling areas policy changes (time of day, …)

5. 6/26/2015 52 st IETF Coordination May have loose central administrator avoid manual updates and configuration reflect changes rapidly (minutes)

6. 6/26/2015 52 st IETF Status updates Want to have reasonably accurate picture But occasional failure + retry acceptable SIP INVITE fails, proxy retries also, may allow grace period (change policy, allow calls for old policy for an hour) Charging not an issue may use a “brownie point” system

7. 6/26/2015 52 st IETF Additional considerations Multicast may be available Not competitors – if anything, GWs are happy not to get a call…