Should SIP be modified to Should SIP be modified to enforce per call billing?enforce per call billing?

Christian HuitemaChristian HuitemaArchitect, Windows NetworkingArchitect, Windows NetworkingMicrosoft CorporationMicrosoft Corporation

Why would we want to Why would we want to track usage?track usage?

To bill for time, distanceTo bill for time, distance To allocate costsTo allocate costs To predict network trafficTo predict network traffic To account for gateway usageTo account for gateway usage

Should we charge for Should we charge for Telephone Access? Yes!Telephone Access? Yes!

Telephone URL: Telephone URL: “tel:12345678901”“tel:12345678901”

User directs “tel:” to User directs “tel:” to selected service, selected service,

Service checks user Service checks user authentication, relays authentication, relays to “Phone-x”to “Phone-x”

Phone-x completes Phone-x completes the call, bills servicethe call, bills service

Service bills user.Service bills user.

SIP works just fineSIP works just fine

Phone-xPhone-x

RVRV

Should we charge for IP Should we charge for IP network usage?network usage?

Plain traffic? No, or not more than basic Plain traffic? No, or not more than basic service!service!

Premium traffic? Possibly!Premium traffic? Possibly!

A B

How to charge for How to charge for premium network usage?premium network usage?

Plain accounting, no controlPlain accounting, no control User marks TOS bits, network keep tabs.User marks TOS bits, network keep tabs.

Application level controlApplication level control Side effect of call set-up, authorizes access. Side effect of call set-up, authorizes access.

Network access controlNetwork access control RSVP transaction, authorizes access.RSVP transaction, authorizes access.

A B

Pros and cons of three Pros and cons of three strategies (1)strategies (1)

User based TOS:User based TOS: Easy to implement, but…Easy to implement, but… Only feedback is monetary, monthlyOnly feedback is monetary, monthly No protection against temporary No protection against temporary

congestion.congestion.

Pros and cons of three Pros and cons of three strategies (2)strategies (2)

Application level control Application level control Feedback on a call per call basis,Feedback on a call per call basis, What of mid-call congestion?What of mid-call congestion? Need to derive network data from Need to derive network data from

application data (fragile!).application data (fragile!).

SIP is not just for voiceSIP is not just for voice INVITE to Chat Room, Video GameINVITE to Chat Room, Video Game Need decision for each media?Need decision for each media?

SIP proxy need not be colocated with SIP proxy need not be colocated with network access!network access!

Pros and cons of three Pros and cons of three strategies (3)strategies (3)

Network access controlNetwork access control RSVP is designed to pass “network RSVP is designed to pass “network

level” signallinglevel” signalling Can use “pre-condition” in SIPCan use “pre-condition” in SIP Use QoS if and when neededUse QoS if and when needed

SIP is not just for voiceSIP is not just for voice Different decision for every media!Different decision for every media!

Remote SIP proxyRemote SIP proxy Use existing AAA framework to bill user Use existing AAA framework to bill user

of remote serviceof remote service

Let’s not pollute SIP,Let’s not pollute SIP,keep a simple framework!keep a simple framework!

SIP already enables billing for SIP already enables billing for gateways, services.gateways, services.

SIP is not just for voice, we don’t SIP is not just for voice, we don’t need to mimic the POTS behavior.need to mimic the POTS behavior.

Billing network resource is better Billing network resource is better handled by network protocols, RSVP.handled by network protocols, RSVP.