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Voice on JANET – SERJUG September 2005
Arron Bowley
Voice Technical Specialist
UKERNA
Agenda
• What is VoIP? Overview, touching on protocols
• Core differences in the nature of IP and TDM.
• What has UKERNA been up to?
• Initial “Requirements feedback”
• Challenges facing voice on JANET
• Tips and Observations
What is VoIP / IPT ?
• Is it Cisco Call Manager ?
• Is it a user using “Netmeeting” across the Internet?
• Is it two PBX’s connected via a VoIP trunk?
• Is it an ISP backhauling voice traffic using IP?
• What about H323? What about SIP?
Comparing Traditional Voice and Data Networks
• Generally in a voice network the intelligence is located in the core of the network and in data networks on the edge.
• Within traditional telephony models carriers and incumbent manufacturers add services if they enhance revenues, whereas PC users add applications when they feel they are useful.
Early VoIP deployments
• PBX manufacturers IP “enable” the PBX with VoIP trunks across intranets (example Meriden IPT gateway trunk card). This enables enterprises to maximise the leverage on their internal network.
• Generally vendor centric.
VoIP LAN Technologies
• Adapters emerged to traverse existing analogue handsets onto IP infrastructures.
• IP Soft Switches such as Cisco’s Call Manager emerge as an alterative model to traditional voice platforms.
• These systems tended to be proprietary and expensive to deploy (not any more).
Pro’s and Con’s (TDM v’s IP)
• If traffic levels are low, channels are not being used therefore bandwidth is wasted.
• If traffic levels are high then calls are “blocked” or “wasted”.
• TDM guarantee's that you have your dedicated 64k switched circuit…reliable.
• In packet switched environments if the traffic is low then the users get more bandwidth
• If the traffic is high it is unlikely that users will get no bandwidth just less.
• IP based telephony gives no guarantee of delivery. It is best efforts only.
Disadvantages of VoIP / IPT
• Single point of failure (phones and computers).• Reliability of systems (9’s).• Scalability of service, ownership of hardware. • Who supports what? Moving lines of
demarcation?• Call Quality across an “uncertain” internet may
be a problem.• No universal directory system, fledgling
regulations, islands of connectivity.
Why Merge Technologies?
• Most organisations have separate voice and data departments?
• In general traditional telephony is very hardware intensive, supplier centric, and BIG.
• When traditional telephony is not being used then circuits are idle and wasted.
• Potential admin saving, one network rather than two.
VoIP’s Various guises
• Registers: Skype, MSN, AOL, GoogleTalk• IP PBX’s• Hybrid TDM solutions – skills based routing, call
centres, presence and voicemail.• Internet Service Telephony providers – Calls are
routed via gateways close to the destination of the source of call. ITSP’s use their own IP networks to route calls thus bypassing the PSTN
• NOS VoIP
So what have we done?
• Commissioned Call manager and upgraded to version 4 for SIP interoperability.
• Interconnected platform to PSTN, and interoperate with a PBX.
• Introduced a SIP trunk to ULCC’s Asterisk open source IP PBX.
• Extended the directory service to dial H323 endpoints, SIP User Access Clients (UAC’s) and Cisco proprietary handsets and soft clients
• Interconnected inter clustered trunks to Falmouth College of Arts and introduced SIP trunks (peers) to Worcester and Lancaster University.
So what have we done?
• Initial prelim tests show call quality as good and no feature clashes.
• Handset interoperability good.• Setup Voice Advisory Group (VAG) to
discuss emerging technologies and strategies with input from IP / TDM managers from JANET and suppliers.
• “Encouraged” Ofcom to take an active part in developments and future research.
Domestic VoIP
• Vonage offer complete coverage of their DSL service (offering unlimited calls in the UK, US and Canada) for £9.99 per month. They also have reasonable tariffs for all countries. FCC made port blocking based on service illegal.
• BT 21CN (century networks) is beginning to churn 144,000 customers per week in Wales. Total amount of lines 30 million. Dismantling their PSTN and legacy telephone platforms for IP in the core.
SKYPE
• Skype, 172 million downloaded clients. Services include Skype Out, and voicemail.
• Recently purchased by Ebay for 1.4 billion pounds (99p?)
• Skype definition : a proprietary, peer-to-peer resource discovery, directory access, and call signalling protocol.
• A paper is being commissioned to look at how Skype works by the VAG.
Interesting document:• http://arxiv.org/ftp/cs/papers/0412/0412017.pdf• Beginning to see Skype being blocked now by local
policies, such as Brunel University.
Mobility and Security
• 3GPP are pursuing SIP as their standard format for the initiation of voice sessions across mobile networks.
• Wireless Handsets (Cisco, Hitachi and Skype handsets?
• Convergence with traditional telephony?
• VoIP Security Alliance (VoIPSA).
The Carriers and Microsoft
• Busy with their “soft phones”…onus on keeping calls on their networks. “Tupperware” marketing price plans.
• Microsoft using similar model as ever with new server model. Very candid about interoperability with standards and other systems… thus “ensuring excellent user experience”.
If its not broke..
• Add more features
• Diversify.. Colour phones, video, EPOC, record your own ring tune, voice mail to email, video marketing on hold, calls to your PDA, icons for your “buddies”.
• Lever your existing product suite…(APC, and CAT 6 cabling, security hyperbole).
Challenges faced for Voice on JANET
• Multiple administration domains• Firewalls and policies• Numbering and directories• Authentication, Access and Authorisation• Integration with existing VoIP / TDM technologies.• QOS (is it required in an over provisioned network)• Multi vendor interoperability• Keeping up with the market(ing) • New Standards • Regulations
Initial Requirements Survey Feedback
• 34 of those organisations that responded provided VoIP services already as a general offering.
• 35. were considering VoIP, but have yet to make a firm decision on trials etc.
• 8 said that they were not considering VoIP
What is it being used for?
• My organisation uses VoIP to connect traditional PBXs 50
• My organisation uses VoIP for a number of remote users 27
• number of users at my organisation use software clients such as SKYPE or Instant Messenger on an informal basis 31
Manufacturers?
• Cisco – 46
• Mitel – 16
• Ericsson – 11
• Nortel – 8
• Avaya – 6
• Siemens – 31
• Other – 17 - Asterisk SIP IPT
How many handsets?
• Less than 50 - 54
• 50-100 - 10
• 100-250 - 7
• 250-500 - 5
• more than 500 - 12
• Other - 10
Interesting titbits
• How many traditional handsets: More than 500 55
• Concerns regarding VoIP – 1. Reliability of VoIP technology 43,2. Changing telephony models and suppliers 22. 3. Scalability of VoIP 244. I have no concerns 9.1• Why not use VoIP? Our current telephony
solution still has a reasonable life expectancy 72
If UKERNA were to offer a Voice Service?
• Connecting together interoperable IP PBX equipment 57
• A central voice offering on JANET for the use of the community offering downloadable software clients and standards based connectivity that can be used to locate users by name, job function or location 51
• A JANET provided standards based directory service (e.g. ENUM) enabling VoIP endpoints to locate each other. 61
Next?
• Trial central register for community to download standards based clients, for users to locate each other and communicate with one another.
• Trail ENUM server.• Produce Fact Sheets and Case Studies through
the VAG• Keep abreast with new platforms – Zultys.• Voice event 16th November 2005 Aston
University.
Things to think about?
• SIP – Register, location and redirector services to be used solely by the community.
• Directory schemas, ENUM and e164.org• Why VoIP? Vendor push? External influences? • System transparency, privacy?• Security, SPIT etc. How many features do I truly
need (proxies), Feature Fatigue, Linux, Scalability and Ducks (how to avoid them)?
Circuit Switched Networks.
• Reliable• Predictable• Easy to manage• Does What its told• Ease of Ownership
Packet Switched Network
• Unpredictable• Tried to train a cat?• Independent• You don’t own a cat!
