1. 1 SIP.edu call 6/23/05SIP.edu by Numbers Ben Teitelbaum SIP.edu Working Group Call June 23 rd, 2005

2. 2 SIP.edu call 6/23/05SIP.edu by Numbers PSTN Big Problem How to SIP from a 12-key phone? IP Desk Phones Cell Phones Legacy Desk Phones

3. 3 SIP.edu call 6/23/05SIP.edu by Numbers Big Question Use E.164 or Not?

4. 4 SIP.edu call 6/23/05SIP.edu by Numbers Use E.164 Numbers Pros –Seamless interoperability with PSTN –No need to change numbers Cons –Not our numbers –Finite resource –Regulatory implications If it walks like a duck… –Seamless interoperability with PSTN (i.e. users should notice that something has changed!)

5. 5 SIP.edu call 6/23/05SIP.edu by Numbers Use Non-E.164 Numbers Pros –Our numbers –Numbers could be more mnemonic –Users will notice that something has changed –Lighter regulatory touch (maybe) –Could fit into E.164 down the road (+87810…) Cons –Calling from PSTN would require two- stage dialing –Calling from a legacy campus environment would require an escape code

6. 6 SIP.edu call 6/23/05SIP.edu by Numbers E.164 Cons out-weigh pros Various implementation options –Dial plan distribution –ENUM –DUNDi –Private ENUM or SIP redirect server Not discussed further here

7. 7 SIP.edu call 6/23/05SIP.edu by Numbers Non-E.164 1/2 Pros out-weigh cons Some design considerations –Numbers derived from SIP.edu addresses, derived from existing extensions, or completely new? –Address structure Flat or hierarchical? Fixed length or variable-length? –Escape codes

8. 8 SIP.edu call 6/23/05SIP.edu by Numbers Non-E.164 2/2 Various implementation options –IVR Gateway –Hash Registrar –Domain Redirect –Others? Lets discuss them… –First, though, a few words on… Address Structure Escape Codes

9. 9 SIP.edu call 6/23/05SIP.edu by Numbers Address Structure * (prefix)(hash) –Requires central authority to resolve hash (prefix)(user)(domain) –Like email –Perhaps 00 could be used as separator (prefix)(domain)(user) –Maps to DNS (e.g. non-E.164 ENUM) –(user) part could be interpreted locally * Thanks to Ed Guy for this taxonomy.

10. 10 SIP.edu call 6/23/05SIP.edu by Numbers Escape Codes Campus dialing plans must designate some escape code to indicate that a SIP.edu number follows –E.g. **EDU (**338) –Local conventions will vary Will variable-length numbers be a problem?

11. 11 SIP.edu call 6/23/05SIP.edu by Numbers IVR Gateway Two-stage dialing through central GW Gateway generates SIP.edu INVITE dbaron@mit.edu = **338 then…dbaron@mit.edu –Speak dbaron at MIT dot e-d-u (voice recognition) –Type 3122217363620614381 (two-tap DTMF codes) –T9 ® predictive textprobably not (proprietary technology; dictionary too big) Voice only (I-IM-R?)

12. 12 SIP.edu call 6/23/05SIP.edu by Numbers Hash Registrar 1/3 Each campus forwards UA registrations to a central registrar Hash SIP.edu address to 8-10 digits dbaron@mit.edu = **338 xxxxxxxxxdbaron@mit.edu md5(dbaron@mit.edu) % 10 9

13. 13 SIP.edu call 6/23/05SIP.edu by Numbers Hash Registrar 2/3 Hash collisions –Make em rare –Resolve through an IVR (Press one for dbaron@mit.edu; two for alice@wonderland.edu. ) dbaron@mit.edualice@wonderland.edu –Or (maybe) dont resolve (Bad luck, you will have to get a new email address if you want to be SIP- able by numbers.)

14. 14 SIP.edu call 6/23/05SIP.edu by Numbers Hash Registrar 3/3 Pros –Knowing an email address knowing the number –Simplifies identity management Users dont get explicit numbers –CGI white page can compute hash and produce number Cons –Only registered UAs reachable by number –Collisions –Requires campus proxy / registrar to pass REGISTERs

15. 15 SIP.edu call 6/23/05SIP.edu by Numbers Domain Redirect 1/4 Mnemonic campus prefixes Central redirect server interprets prefixes and redirects to campus proxy dbaron@mit.edu = **338648 xxxxxdbaron@mit.edu = **338 xxxxx00 648 MIT Locally interpreted by MIT (could be extension or username hash)

16. 16 SIP.edu call 6/23/05SIP.edu by Numbers Domain Redirect 2/4 Default Campus Prefixes

17. 17 SIP.edu call 6/23/05SIP.edu by Numbers Domain Redirect 3/4 Some defaults collide –mit = niu = 648 Others have colliding prefixes –28 (bu) –282 (cua) –282875 (auburn) Suggested policy –First come, first served –Cant have a default unless its yours –Resolve conflicts Different lengths –mit + 5-digits –niu + 6-digits Numbering knowledge –mit + [2357][0-9]{4} –niu + [468][0-9]{4} Use a non-default prefix –645 (nil)

18. 18 SIP.edu call 6/23/05SIP.edu by Numbers Domain Redirect 4/4 Pros –Each campus can number its own way Existing extensions Username hash New numbers –Reaches all campus phones –Prefix gold rush Cons –Prefix gold rush –Prefix collision resolution could get tricky I like this option! Full Disclosure…

19. 19 SIP.edu call 6/23/05SIP.edu by Numbers SIP.edu Reachability: Present and Future NG DeviceKeypad NG DeviceSIP.edu v1.0 Keypad To: From:

20. 20 SIP.edu call 6/23/05SIP.edu by Numbers SIP.edu Reachability: Present and Future NG DeviceKeypad NG DeviceUA RegSIP.edu v1.0 KeypadUA Reg To: From:

21. 21 SIP.edu call 6/23/05SIP.edu by Numbers SIP.edu Reachability: Present and Future NG DeviceKeypad NG DeviceUA RegSIP.edu v1.0 KeypadUA Reg, ISNISN To: From: