Open Source carrier-grade platforms

1
Open Source carrier-grade platforms

• Adrian Georgescu
• AG Projects
• http//ag-projects.com

2
Current telecommunications landscape

• Circuit switched networks (SS7 and ISDN) reached
  their end-of-life
• Replacement for signaling protocols has been
  proposed by ITU (H323) and IETF (SIP)
• Other alternatives MGCP/Megaco, Skype, Skinny,
  IAX
• All vendors support SIP today, it is a common
  denominator in the vendor landscape
• From the old PSTN only the E.164 numbering plan
  remains

3
SIP protocol features

• SIP is a horizontal protocol which allows
  end-points to find each other and initiate
  sessions over the Internet (any type of sessions)
• Intelligence is distributed among participating
  nodes
• SIP makes use of other proven protocols for
  addressing, security and scalability, it did not
  re-invent the wheel (DNS, HTTP, TLS)
• SIP allows both telephone numbers or e-mail
  format for addressing user_at_domain.com
• SIP enabled convergence between fixed and mobile
  networks, you can change access medium, device or
  provider and it still works.

4
Business models based on SIP

• Classic PSTN termination service with per minute
  charging
• ADSL service complement (bundling Internet access
  with VoIP)
• Telephone numbers can be sold separately
  (recurrent charges)
• Company PBXs interconnected via IP (project based
  approach)
• SIP service subscription (free calls to other SIP
  phones)
• Closed garden/walled garden models - better chose
  Open, the more subscribers are restricted the
  bigger the churn

5
Open garden versus Walled garden

• Walled gardens so far have been motivated by poor
  implementations, lack of clarity over new
  business models, the push of session border
  controllers
• PSTN and E164 numbering plan were a success
  because one was able to connect to everybody else
  (universal service)
• Is important to allow dialing of both E164
  numbers and SIP URIs
• By the time you finish building up your walled
  garden, the customers will be safely outside -
  Adrian Georgescu
• If you can dial a SIP URI and you can be called
  by a SIP URI than you have access to VoIP
  otherwise is just an emulation of classic PSTN -
  Henry Sinnreich

6
Open Source versus Closed Source

• Todays speed of development can be achieved only
  through OS
• Before black box switch developed by a vendor,
  the switch worked in controlled environment (SS7
  network). Development cycle was long and testing
  in a closed lab was enough
• Today you have a combination of services/servers
  DNS, SIP, ENUM, NAT traversal, all are exposed to
  the Internet, all are moving targets, all are
  subject to continuous development
• On the Internet the things work differently, is a
  not a controlled environment
• DoS attacks can bring down a service, the
  solution is to use similar countermeasures, a
  distributed service infrastructure

7
Deployment stage

• During installation of an Open Source solution,
  the Service provider can learn how to build the
  platform which is useful for disaster recovery
  should such event arise
• Installation log
• Source code
• Documentation for individual components
• As-built schematic (platform blueprint)
• Further customization of deployed solution

8
Business resilience

• SIP is a moving target. The companies developing
  SIP are fairly young, there are risks which can
  be minimized
• Large operators should not bet on one vendor
  alone. Use a main vendor for the initial solution
  and a back-up vendor. They should know about each
  other and should work together
• Two vendors may develop a stronger product and
  solve interoperability issues that will appear
  when you connect to other SIP networks
• Get/train specialists in house, get familiar with
  the Open Source solutions used
• Business is more secure with a large knowledge
  base

9
Requirements for carrier-grade SIP services

• Compliancy with standards, interoperability and
  best practices
• Knowledge base, the biggest Open Source unfair
  advantage
• Integration with other systems PSTN
  interconnect, integration with other carrier
  business units like provisioning and billing
• Solution scalability and survivability

10
Ingredients for carrier-grade SIP services

• SIP signaling (Proxy/Register/Redirect)
• E.164 number translation (ENUM)
• NAT traversal capability (ICE in the client or
  far-end server based)
• Mediation and accounting (critical for a carrier
  business)
• Provisioning (critical for a carrier business)
• Emulation of existing telephony services (class
  5), Applications (Voicemail, Voice to email,
  Conferencing, Interactive messaging and
  Presence), End-user devices (software or
  hardware)

11
SIP signaling (SIP Proxy/Registrar/Redirect)
SIP Express Router, the largest SIP
Proxy/Registrar installed base today. SER is
used by major carriers all over the world, is the
best example of how Open Source community could
merge quickly into a product features that
commercial vendors later add to their
offerings OpenSER, a fork of SER with enhanced
carrier-grade features has been spawned
at http//OpenSER.org Visit Booth 943 to get
in contact with some SER developers
12
ENUM and number portability

• ENUM is a DNS based system, the solutions are
  also coming from the Open Source community (BIND
  and Power DNS)
• ENUM link VoIP islands together
• ENUM links PSTN with IP
• ENUM provides an internet based number
  portability solution (as opposed to closed IN
  systems) - Local Number portability panel on
  Thursday 130 PM
• ENUM is a central DNS database, no need to
  configure individual switches anymore, save money
  on operations

13
The importance of Internet global directories

• Global directories are critical for increasing
  the adoption of Open standards
• ENUM-driven number range 43780 (Austria)
• ENUM-driven number range 87810 VISIONng
• E164.org allows exchange of numbering resources
  between VoIP Operators
• DNS allows end-users to customize their SIP
  address by registering their own domain, my email
  address is also my SIP address ag_at_ag-projects.com

14
Media Proxy - geographical distributed NAT
traversal solution

• MediaProxy is the most used far-end NAT traversal
  solution deployed in hundreds of installations
  across the world in tandem with SIP Express
  Router
• MediaProxy is a practical example of how to
  implement NAT traversal without a central session
  border controller
• MediaProxy is an example of how you can provide
  load sharing and resilience for far-end NAT
  traversal without single a point of failure

15
How to solve scalability and survivability

• Carrier-grade solutions must be scalable and
  resilient. This should be achieved through
  design
• Presence in multiple geographical locations
• Load sharing among multiple sites
• Resilience against DoS attacks
• Automatic failover on server failure or site
  failure
• Plug and play capacity upgrade with zero
  configuration
• Only a truly P2P SIP system can achieve both
  survivability and scalability.

16
Best ingredients today are Open Source

• SIP and DNS have been traditionally developed by
  Open Source community, other ingredients have
  been migrated to Open Source
• Linux operating system Debian (http//www.debian.
  org)
• SIP signaling OpenSER (http//OpenSER.org)
• NAT traversal MediaProxy (http//mediaproxy.ag-pr
  ojects.com)
• ENUM (BIND http//www.isc.org or PDNS
  http//www.powerdns.com)
• CDR mediation CDRTool (http//ag-projects.com/CDR
  Tool.html)
• Accounting FreeRadius (http//www.freereadius.org
  )
• Database MySQL (http//www.mysql.com)
• Voicemail and voice to email Asterisk
  (http//www.asterisk.org)
• Provisioning SOAP/XML API

17
Platform blueprint
18
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19

• This presentation is available at
• http//ag-projects.com/docs/Present/MultimediaServ
  icePlatform.ppt
• http//ag-projects.com/docs/Present/MultimediaServ
  icePlatform.pdf
• Thank you,
• Adrian Georgescu
• Email/SIP ag_at_ag-projects.com