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http://freenum.org/ . ISN: Free Numbers Fast. Dennis Baron, MIT Ben Teitelbaum, Internet2 John Todd, Loligo September 13 th , 2006 Fall VON, Boston, MA. …. …. PSTN. foo.edu. …. …. foo.edu. Internet. …. …. foo.edu. VoIP Service Provider. …. …. VoIP brought to you by…. foo.edu.
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http://freenum.org/ ISN: Free Numbers Fast Dennis Baron, MITBen Teitelbaum, Internet2John Todd, Loligo September 13th, 2006Fall VON, Boston, MA
… … PSTN foo.edu
… … foo.edu Internet
… … foo.edu VoIP ServiceProvider
… … VoIP brought to you by… foo.edu
RTC brought to you by… foo.edu … …
Old World / New World Radically new devices / services +1-734-352-7031 ben@internet2.edu Deep bureaucratic hierarchy The world is flat (almost) Telco provider control Be your own provider
SIP.edu • Email address as RTC handle • 250k .edu users sip:dbaron@mit.edu
Unfortunately, it’s hard to enteralphanumeric addresses on this:
ISN Numbers… 21232*270 Domain-local(you allocate) ITAD(IANA allocates)[RFC3219]
ITAD Subscriber Numbers • Defined by Telephony Routing over IP (TRIP) [RFC3219] • Globally unique • Lots of them (256 through 232-1) • IANA is already set up to allocate • ISN resolution works just like ENUM
Corporate Enterprises • Sterling National Bank • Apple Computer ISN Trial Participation • 67 domains from 14 countries Academic • Internet2 • Hofstra University • UCLA • MIT • Stanford • University of Alaska Fairbanks • University of California, Berkeley • Florida State University • University of Manitoba (Canada) • University of Oregon • Royal Institute of Technology (Sweden) • NE Worcestershire College (England) • Trent University (Canada) • University of North Carolina • University of Texas, Austin • Columbia University • UCSD • Taiwan Academic Network ITAD Assignments • 153 domains from 17 countries VoIP Solution Providers • Tello • Iotum • Digium • Nokia VoIP Service Providers • Free World Dialup • Stealth Communications • SIPcall.com • RCN Corporation • VoIPteq • SIP Broker • TellMe • PhoneGnome Others • BizFu • Manitoba New Democratic Party • Packet Clearing House Government • State of Oregon
Costs • ITAD Subscription: Free • License restrictions: None • Monthly recurring: None • Tech time: Small • User instruction: Medium
Benefits1/2 • Free VoIP calling (expected zero-cost) • Future-proof numbering • Does not require change of equipment • Easy user memorization • Unique format makes routing and CDRs obvious
Benefits2/2 • Incremental deployment of dialing plan • Even works with most SIP-only iPBX systems • Does not require VPNs, Switch fabrics, or contracts • No question of "ownership" of number space • No contradictory routes possible • Low technology hurdles to jump (standards-based!)
sip:bdr@internet2.edu mailto:bdr@internet2.edu sip:bobr_621@att.sbc.com ENUM in a Nutshell • Take an E.164 number • Convert it to FQDN • Query DNS for NAPTRs • Apply resulting regexs to get list of URIs: +1-734-913-4257 7.5.2.4.3.1.9.4.3.7.1.e164.arpa. e164.arpa. 1.e164.arpa. 4.3.7.1e164.arpa. x.x.x.1.e164.arpa.
sip:bdr@internet2.edu mailto:bdr@internet2.edu sip:bobr_621@att.sbc.com ISN in a Nutshell • Take an ISN • Convert it to FQDN • Query DNS for NAPTRs • Apply resulting regexs to get list of URIs: 4257*260 7.5.2.4.260.freenum.org. freenum.org. 260.freenum.org. Note: We are working to ensure that the ISN root zone will be administered on behalf of the ISN user community by a neutral, non-profit organization. Following the trial, the root may or may not be “freenum.org”.
3 Easy Steps • Request an ITAD from IANA • Publish your ITAD/ISN information in DNS • Option1: Put full NAPTR in root zone*.xxx.freenum.org IN NAPTR 100 10 "u" "E2U+sip” "!^\\+*([^\\*]*)!sip:\\1@sip.big.edu!" . • Option2: Have root zone delegate to your own nameservers • Enable inbound / outbound ISN calling • Recipes for SER and Asterisk available
Asterisk Implementation • Outbound dialplan (one line!):Exten => _012.,1,Dial(SIP/${ENUMLOOKUP(${EXTEN},sip,i,freenum.org)}) • Inbound: • No changes if your system supports inbound SIP extension calls
SER Implementation1/2 • Inbound: • No changes if your system supports inbound SIP extension calls • Otherwise, can alias ISNs to URIs and resolve (see ISN Cookbook for example)
SER Implementation2/2 • Outbound:route[3] { # Assert that uri is in proper format if (! (uri =~"^sip:[0-9]+\*[0-9]+@")) { xlog("L_CRIT", "%Tf: route[3] called with improper ISN\n"); break; }; if (!exec_dset("/usr/local/bin/isn-resolv.pl")) { sl_send_reply("404", "Not Found"); break; } else { xlog("L_INFO", "%Tf: Routing outbound ISN Call %ru(From [%fu], To [%tu])\n"); # Relay the message if (!t_relay()) { sl_reply_error();}; };} # end of ISN route block
“Dumb” iPBX Implementation • Pseudocode using public helpers: if $DIALEDNUMBER starts with "012" then strip off "012" from $DIALEDNUMBER send SIP INVITE to $DIALEDNUMBER@freenum.orgelse dial-as-normal
MIT Deployment • Motivation • Evolution of our SIP infrastructure • Advancing support of early technology adopters • While maintaining interoperability with legacy technologies • Support for innovation on the “experimental campus” • Broaden our federation options • But still encourage the migration to full URI support!
MIT Deployment • Use Cases • Student can be called in her dorm room from friends and family using non-MIT VoIP services that use SIP analog terminal adapters • MIT press editor can collaborate with authors using his traditional PBX ISDN phone • MIT researchers can reach experimental voice recognition servers at a remote research lab from any campus phone
MIT Deployment • Issues • Easy to implement “native” ISN dialing on our SER based SIP proxies (but we haven’t done this yet) • Legacy PBX (Lucent 5ESS) couldn’t seem to cope with the “*” • Implemented Asterisk server to collect digits and route ISN calls
DNS lookup for 262 freenum.org FWD phone rings MIT SIP Proxy Servers Campus Network Internet MIT Asterisk Server SIP/PRI Gateway MIT PBX Server prompts for number: User dials 248911* Server prompts for domain: User dials 262# MIT PBX user dials *0 MIT Deployment
Self-Demo • Call: +1-712-432-7935 • Listen to the IVR • Enter an ISN • 87225*270 - MIT Shuttle Track • 2425*259 - Tello “success” message • 1234*256 - Recorded monkeys, echo test
For More Information • ISN Cookbook, FAQ, and other info • http://freenum.org/ • Contact us: • Ben Teitelbaum • ben@internet2.edu | 7031*260 • John Todd • jtodd@tello.com | 2203*256 • Dennis Baron • dbaron@mit.edu | 21232*270 • Q&A right now