Austrian ENUM Trial Demo

1
Austrian ENUM Trial Demo

• Michael Haberler
• Otmar Lendl
• Alexander Mayrhofer
• nic.at

2
so what are we going to show

• single user ENUM
• recap calls based on SIP address-of-record
  adressing
• call using 43 geographic number
• calls based on 87810 ENUM overlay (Internet
  country code)
• provisioning of an individual ENUM entry
• crossing the Internet/PSTN boundary
• default routing to PSTN, tel record, 2stage
  dialing
• business ENUM
• connecting PBXes MX record analogy
• ENUM as a least-cost-routing criterion between
  PBXes
• look at the wildcard regexp record

3
on the demo setup

• Cisco Phones with multiple line capability
• left phone is
• line 1 sipaxelm_at_nic.at43.at
• right phone is
• line 1 sipmah_at_nic.at43.at
• line 2 sip19343_at_fwd.pulver.com
• line 4 sip201_at_samuel.ops.at43.at PBX line

4
Call within a SIP domain
ENUM DNS
SIP
SIP
server
server
sipmah_at_nic.at43.at
sipmah_at_nic.at43.at
session
sipaxelm_at_nic.at43.at
sipmah_at_nic.at43.at
sip18341_at_fwd.pulver.com
sip19343_at_fwd.pulver.com
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E.164 adressing with ENUM
IN NAPTR 4.2.7.9.3.5.2.1.3.4.e164.arpa. ?
... NAPTR ... "!.!sipmah_at_nic.at43.at!"
4312539724
sipmah_at_nic.at43.at
session
sipaxelm_at_nic.at43.at
sipmah_at_nic.at43.at
sip18341_at_fwd.pulver.com
sip19343_at_fwd.pulver.com
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Call across SIP domains
DNS lookup for SRV record fwd.pulver.com
sip19343_at_fwd.pulver.com
sip19343_at_fwd.pulver.com
session
sipaxelm_at_nic.at43.at
sipmah_at_nic.at43.at
sip18341_at_fwd.pulver.com
sip19343_at_fwd.pulver.com
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cross-domain call ENUM
IN NAPTR 7.3.5.7.3.2.2.4.2.6.0.1.8.7.8.e164.arpa.
?
... NAPTR ... "!.!sip19343_at_fwd.pulver.com!"
DNS SRV lookup fwd.pulver.com
878106242237537
sip19343_at_fwd.pulver.com
session
sipaxelm_at_nic.at43.at
sipmah_at_nic.at43.at
sip18341_at_fwd.pulver.com
sip19343_at_fwd.pulver.com
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how to get from Internet to the PSTN back?

• PSTN to Internet
• number range routed to media gateway
• plain PBX model or interconnection as a telco
• two stage dialing
• in both cases ENUM useful on Internet leg
• Internet to PSTN
• no VoIP ENUM record at all bounce to PSTN
• ENUM tel record explicit call forward to PSTN

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business ENUM scenario

• connecting PBXes using ENUM as least cost routing
  criterion
• NAPTR regexps and wildcards are useful (beyond
  the religious argument)
• recap how mail servers work
• how ENUM enabled PBXes work
• demo PBX to PBX call with ENUM LCR routing

10
how do mail servers work?

• Destination-driven routing mechanism
• mail exchange (MX) record in DNS
• possibly a wildcard as a default mechanism
• inbound MX record attracts traffic destined
  for a domain
• outbound mail processing involves MX lookup to
  find mail server

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how do PBXes with ENUM routing work?

• callee-driven routing by ENUM NAPTR entry
• NAPTR record(s) covers PBX number and DDI
  extensions
• possible all extensions with a wildcard NAPTR
• MX record for domain NAPTR for PBX
• NAPTR attracts traffic to PBX
• outbound call processing involves NAPTR lookup
• policy decision for least cost routing
• if possible, do call via Internet
• if not, use the PSTN

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hows the Uni Bratislava PBX provisioned?
wildcard NAPTR record starting at 421257296
sh host -t NAPTR 6.6.6.6.9.2.7.5.2.1.2.4.e164.arp
a 6.6.6.6.9.2.7.5.2.1.2.4.e164.arpa NAPTR 100 10
"u" "E2Usip" "!\\421257296(.)!sip2\\1_at_stuba.
sk!"

• for any extension X if we lookup 421257296
  extension, the regexp match returns
  sip2extension_at_stuba.sk
• example we dial 421257296555 on Asterisk, the
  number gets replaced with sip2555_at_stuba.sk

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Classical PBX-PBX call
442079025500
442079025500
PCM or SIP or IAX or H.323
PCM or SIP or IAX or H.323
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PBX2PBX using ENUM
ENUM
421257296666
PCM or SIP or IAX or H.323
PCM or SIP or IAX or H.323
sip2666_at_stuba.sk
IN NAPTR 6.6.6.6.9.2.7.5.2.1.2.4e164.arpa. ?
... NAPTR ... "!\\421257296(.)!sip2\\1_at_stuba.s
k!"
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Summary

• single user scenario
• ENUM E.164 number space integrates PSTN and
  Internet adressing easy on users, gateway
  operation
• E.164 ENUM overlay is the way to go for SIP
  service providers if PSTN interworking is
  required
• telco cooperation helps for routing numbers,
  tariffs
• PBX scenario
• PBX owners can opt in uncoordinated with others
• calls between ENUM PBXes drop onto Internet
  without further configuration if call partners do
  likewise
• no telco cooperation needed, just ENUM service
• PBX manufacturers hello!! wakup call!!

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• http//enum.nic.at/ietf57.ppt