implementing voip at an institution using the sip.edu - terena

Dennis Baron, May 14, 2006Page 0np143

SEEREN2 Winter School, Kopaonik, Serbia, VoIP workshop

Dennis Baron

Milivoje Mirovic, AMRES

March 12th, 2007.

Implementing VoIP at an institution using the SIP.edu cookbook


Motivations• Provides a useful service

• Easy to get started

• Lots of options

• Facilitates inter-campus communications

• Opens the way for innovation

• Build I/T staff skills

• Help break down organization/cultural barriers

• Encourage early technology adopters

• Set PBX migration path


Means

• Publishing “cookbook” with several alternative “recipes”

• Obtaining corporate sponsorship and promotional pricing

– Cisco, Avaya, etc.

• Build community of SIP practitioners


Goals

• SIP ConnectivityBuild a large base of SIP-reachable NREN users by making existing campus PBX, Centrex, and VoIP systems reachable via SIP

• SIP AddressingFacilitate the convergence of communications identities by promoting the use of email addresses for voice and multimedia communications


SIP Connectivity


Components

• DNS Server– Add SIP SRV records to existing servers

• SIP Proxy Server– Also acts as SIP registrar– Can support “aliases” for legacy phone numbers– Mimics campus dial plan

• LDAP Server (or other source of directory data)– Has mapping of email to phone number

• SIP Gateway– Connects to existing PBX or Centrex– Could also connect to proprietary VoIP system


PBX PSTN

SIP/PRIGateway

SIP.edu Configuration

SIP Server

Campus Network

Internet2

DNS Server

LDAP Server

SIP user wants to call [email protected]


PBX PSTN

SIP/PRIGateway

DNS SRV Lookup

SIP Server

DNS Server

LDAP Server

Campus Network

Internet2

DNS SRV

DNS lookup for MIT.EDU


PBX PSTN

SIP/PRIGateway

SIP INVITE

SIP Server

DNS Server

SIP

LDAP Server

Campus Network

Internet2

SIP INVITE to [email protected]


PBX PSTN

SIP/PRIGateway

LDAP Lookup

SIP Server

DNS Server

LDAP

LDAP Server

Campus Network

Internet2

LDAP lookup for dbaron – returns x21232


PBX PSTN

SIP/PRIGateway

Call Sent to PBX Gateway

SIP Server

DNS Server

SIP

LDAP Server

Campus Network

Internet2

SIP INVITE to x21232 via Gateway


PBX PSTN

SIP/PRIGateway

Media Stream via Gateway to PBX

SIP Server

DNS Server

RTP

LDAP Server

Campus Network

Internet2

SIP user talks to [email protected] x21232


PBX PSTN

SIP/PRIGateway

Sip to SIP Calling

SIP Server

DNS Server

RTP

LDAP Server

Campus Network

Internet2

SIP user talks to [email protected] his SIP phone


PBX PSTN

SIP/PRIGateway

SIP to PBX and PSTN Calling

SIP Server

DNS Server

LDAP Server

Campus Network

Internet2

Campus SIP user calls 21232 or 912129990000


Architecture (Phase 1)

SIPProxyDNS SIP-PBX

Gateway PBX

INVITE (sip:[email protected])

INVITE(sip:[email protected])

DNS SRV query sip.udp.bigu.edu

telephoneNumberwhere mail=”bob”

PRI / CASbigu.edu

CampusDirectory

SIP User Agent

Bob's Phone


Call Flow Example

• SIP DNS lookup for MIT.EDU points to SIP proxy

– Sends INVITE to [email protected] to proxy

• SIP proxy checks MIT directory

– Maps call to PBX extension – eg. [email protected]

• SIP proxy checks dial plan

– Routes call to PBX gateway

• PBX rings phone


DNS

INVITE (sip:[email protected])DNS SRV query

sip.udp.bigu.edu

bigu.edu

SIP User Agent

Architecture (Phase 2)

locationDB

If Bob has registered, ring his SIP phone; Else, call his extension through the PBX.

REGISTER(Contact: 207.75.164.131)

INVITE (sip:[email protected])

SIPProxy

SIPRegistrar

Bob's SIP Phone


Examples – Vendor Solution• Avaya

– SIP Converged Communications Server (CCS)

– Communications Manager Media Server and Gateway

• Handle Based Dialing service (LDAP plugin)

SIP~n~Go Starter Kit


Examples – All-in-One

• Asterisk as both proxy and gateway

• Soekris 4801 server with SangomaT1/E1 card

– Approximately $675USD

• Astlinux (Asterisk + micro Linux)

• Directory lookup via file or LDAP

Still under development and testing


“gaps”

• SIP is more than voice– Video and IM are important too– Presence services change the user experience

• Chickens without eggs only gets you half way– We’ve made everybody SIP reachable, now who’s going to

call them?

• The 12-digit keypad problem will be with us for awhile

– What do we do until the devices have a 21st century user interface?


Deployments


Cookbook Status

See http://mit.edu/sip/sip.edu/

• Sections have been added– Cisco SIP Proxy Server (CSPS)– Cisco Gateways

• Missing pieces– Asterisk gateway

• Some information is over two years old now– Proxy and gateway sections could be updated for current

releases– User agent section is also dated

http://mit.edu/sip/sip.edu/


Vendor Support SIP.edu work

• Avaya– Developed LDAP plug-in for directory integration– Sponsored first SIP.edu hands-on workshop

• Cisco– Discount package for CSPS

• Comcast– Sponsored first SIP.edu implementers workshop

• Pulver.com– Developed BlueLava package for SER/Asterisk– Workshop support – software and instruction


Addressing

ISN


+1-734-352-7031

Deep bureaucratic hierarchy

Telco provider control

[email protected]

The world is flat (almost)

Be your own provider

Radically new devices / services

Old World / New World


Why Phone NUMBERS?• Users should not be burdened with device addresses, when it’s

people they really care about

• Addresses should be mnemonic and empower enterprises to manage the identities of their users

sip:[email protected]

• It’s time to put E.164 phonenumbers behind us!

• A.G. Bell did not say:

“+1-617-252-1232, come here. I need you!”


Cell Phones

IP Desk Phones Legacy Desk

Phones

PSTN

Old World*

Emerging New World

Solution:numeric aliases* Transitional period during which we have to

support these devices will last a long time!

How to SIP from a 12-key phone?


• 4257*260

• ITADs–Defined by Telephony Routing over IP (TRIP) [RFC3219]

–Globally unique –Lots of them (232 - 256)–IANA is already set up to allocate

• ISN resolution works just like ENUM

locallyassigned

IP Telephony Administrative Domain (ITAD)

ITAD Subscriber Numbers (ISN)


Academic– Internet2– Hofstra University– UCLA– MIT– Stanford– University of Alaska Fairbanks– University of California, Berkeley– Florida State University– University of Manitoba– University of Oregon– Royal Institute of Technology– NE Worcestershire College– Trent University– University of North Carolina– University of Texas, Austin– Columbia University– UCSD– Taiwan Academic Network

Corporate Enterprises– Sterling National Bank– Apple Computer VoIP Service Providers

– Free World Dialup– Stealth Communications– SIPcall.com– RCN Corporation– VoIPteq– SIP Broker

Other– BizFu (web hosting)– Manitoba New Democratic Party– Packet Clearing House– +36 others

VoIP Solution Providers– Tello– Iotum– Digium

Government– State of Oregon

Assigned ITADs (as of 3/15/06)


• Trial just starting up– Supported by Internet2, Packet Clearing House,

MIT, Tello

• ISN Cookbook Published– Recipes for SER and Asterisk

• 103 ITADs assigned so far– http://www.iana.org/assignments/trip-parameters

ISN Status

http://www.iana.org/assignments/trip-parameters


1. Request an ITAD from IANA– Simple piece of email– Approximate two week turnaround

2. 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:\\[email protected]!" .

– Option2: Have root zone delegate to your own nameservers3. Enable inbound ISN calling4. Enable outbound ISN calling

– Option1: Native ISN lookup– Option2: Using Tello SIP redirector– Option3: Using Tello private ENUM

ISN in Four Easy Steps


E.164 GDS ISN

+1-734-913-4257

Phone numbers

ITU, national government, …

Hierarchical / geographical

Non-numeric Characters

Ignored No * Only Yes

Varies by country???

00 1 189 7349134257

Public ENUM + multiple private ENUMs

H.323 video users

4257*260

Huh?

IANA

local*domain

With domain owner’s cooperation

ViDeNet, national gatekeepers

Hierarchical / geographical/ organization

One space

With domain owner’s cooperation

One space

SIP AOR

Example [email protected]

Familiarity Email addresses

Delegating Authority

ICANN, TLD registrars

Address Structure

local@domain

Portability With domain owner’s cooperation

Fragmentation One space

E.164 vs. GDS vs. ISN vs. SIP


ENUM Testing in SIP.edu

So is the answer just another root for .edu?

• Test ENUM server at SipEduEnum.pulver.com

• Test SIP redirect server too

sip:+<countrycode><number>@redirect.SipEduEnum.pulver.com:5062


– More Information?

• SIP.edu Web Page– http://www.internet2.edu/sip.edu/

• Mailing list (see web page)– mailto:[email protected]

• Thursday conference calls (2:00 Eastern)– sip:[email protected]

• SIP.edu Cookbook– http://mit.edu/sip/sip.edu/

• ISN Cookbook– http://freenum.org/

http://freenum.org/


– More Information?

Contact:Milivoje Mirovic, [email protected]:[email protected]

Dennis Baron, MITmailto:[email protected]:[email protected]

mailto:[email protected]

implementing voip at an institution using the sip.edu - terena

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