Should SIP be modified to enforce per call billing? Christian Huitema Architect, Windows Networking Microsoft Corporation

Why would we want to track usage? To bill for time, distance To bill for time, distance To allocate costs To allocate costs To predict network traffic To predict network traffic To account for gateway usage To account for gateway usage

Should we charge for Telephone Access? Yes! Telephone URL: “tel: ” Telephone URL: “tel: ” User directs “tel:” to selected service, User directs “tel:” to selected service, Service checks user authentication, relays to “Phone-x” Service checks user authentication, relays to “Phone-x” Phone-x completes the call, bills service Phone-x completes the call, bills service Service bills user. Service bills user. SIP works just fine SIP works just fine Phone-x RV

Should we charge for IP network usage? Plain traffic? No, or not more than basic service! Plain traffic? No, or not more than basic service! Premium traffic? Possibly! Premium traffic? Possibly! A B

How to charge for premium network usage? Plain accounting, no control Plain accounting, no control  User marks TOS bits, network keep tabs. Application level control Application level control  Side effect of call set-up, authorizes access. Network access control Network access control  RSVP transaction, authorizes access. A B

Pros and cons of three strategies (1) User based TOS: User based TOS:  Easy to implement, but…  Only feedback is monetary, monthly  No protection against temporary congestion.

Pros and cons of three strategies (2) Application level control Application level control  Feedback on a call per call basis,  What of mid-call congestion?  Need to derive network data from application data (fragile!). SIP is not just for voice SIP is not just for voice  INVITE to Chat Room, Video Game  Need decision for each media? SIP proxy need not be colocated with network access! SIP proxy need not be colocated with network access!

Pros and cons of three strategies (3) Network access control Network access control  RSVP is designed to pass “network level” signalling  Can use “pre-condition” in SIP  Use QoS if and when needed SIP is not just for voice SIP is not just for voice  Different decision for every media! Remote SIP proxy Remote SIP proxy  Use existing AAA framework to bill user of remote service

Let’s not pollute SIP, keep a simple framework! SIP already enables billing for gateways, services. SIP already enables billing for gateways, services. SIP is not just for voice, we don’t need to mimic the POTS behavior. SIP is not just for voice, we don’t need to mimic the POTS behavior. Billing network resource is better handled by network protocols, RSVP. Billing network resource is better handled by network protocols, RSVP.