1-samsung voip-cdg presentation 2

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Overview of Voice Over I nternet P rotocol

P urva R. Rajkotia,

Samsung Electronics

November 4 ,2004



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• Presentation Outline – History of VoIP – What is VoIP? – Components of VoIP

– VoIP Protocols – Basic VoIP Call – VoIP Standards – Regulatory Environment – Benefits of VoIP

– Challenges for VoIP – VoIP on CDMA2000 – Business Applications Benefits – Technology Adoption

Overview of Voice Over Internet ProtocolOverview of Voice Over Internet Protocol



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Some Interesting IP factsSome Interesting IP facts

• 50% of all ent erprise telephone st at ions sold in U S w ere I P based -I n-Stat/ M D R

• M ore than 30% of U S and U K populat ion w il l subscribe to V oI P service in t he next 3 years -M ercer M anagement Group

• W orldw ide revenue f rom the corporate I nt ernet Protocol (I P) telephobusiness w il l grow f rom $ 1 billion by the end of this year to $ 5.5 bill

in 2008.-Radicati Group



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History of VoIPHistory of VoIP

• VoIP came into existence as a result of work done by fewhobbyists in Israel in the year 1995,when onlyPC-to-PC communication was in vogue.

• Later on during 1995, Vocaltec Inc. released Internet Phonesoftware.

• The software used to compress the voice signal, convert itinto voice packet and finally ship it over the internet. Thesound quality was not even close to that of the standardequipment in use at that point of time. This attempt was the

first IP phone that came into existence.

• VoIP has made great progress since then.



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So, what is VoIP?So, what is VoIP?

• Voice Over Internet Protocol (VoIP) is the assembly of voiceinto IP data. This data can be transmitted over an IPnetwork to an addressable (IP address) destination.

• Voice calls look like data calls.

• VoIP calls are packet switched and analog calls are circuitswitched.

• Packet switched is data that can be routed through differentroutes on a network to reach a destination.

• Circuit Switched is a connection where a physical path isdedicated between two end points.



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So, what is VoIP?So, what is VoIP?

CODEC

COMPRESS

CREATE PACKET

ADD HEADERS

NETWORK

Analog

Digital

PROCESS HEADER

DECOMPRESS

CODEC

NETWORK

Analog

Digital



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Components of VoIPComponents of VoIP



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Components of VoIPComponents of VoIP

• The gateway converts the signals from the traditionaltelephony interfaces (POTS, T1/E1,ISDN) to VoIP.

• An IP phone is a terminal that has native VoIP support andcan connect directly to an IP network.

• The server provides management and administrativefunctions to support the routing of calls across theynetwork.

• In a system based on H.323, the server is known as agatekeeper. In SIP/SDP, the server is a SIP server.

In a system based on MEGACO or MGCP, the server is callagent.

• The IP network can be a private network, an Intranet or theInternet.



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VoIP P rotocol Stack VoIP P rotocol Stack

PHYSICAL

LINK

NETWORK (IP)

UNRELIABLETRANSPORT (UDP)

RELIABLE TRANSPORT(TCP)

RAS

(H.225)

DNS RTP/RT

CP

H.245 Q.931

(H.225)DNS

ADDRESSINGADDRESSING AUDIO CODEC DTMF

PRESENTATION



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VoIP ProtocolsVoIP Protocols• Multicast IP – The objective here is to send one packet and have it

received at many destinations. In order to propagate thesedatagrams to multiple destinations, the routers within the networkinfrastructure operates with modified routing protocols. Thesemulticast routing protocols construct logical spanning tree, whichdescribes how the multicast traffic flows to the end stations.

• Real Time Transport protocol provides end-to-end delivery servicefor data that requires real time support, such as interactiveaudio and video. The services provided by RTP includes payloadtype identification, sequence numbering, time stamping anddelivery monitoring.

• Real Time control Protocol monitors the quality of service andconveys information about the participants in an ongoing session.It is based on the periodic transmission of control packets to allparticipants in the session, using the same distributionmechanism as the data packets.



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VoIP ProtocolsVoIP Protocols

• Resource Reservation Protocol ( RSVP) defines the QoS and the

mechanisms to provide the QoS. RSVP is a control protocol,therefore it works in collaboration with-not instead of- traditionalrouting protocols.

• Session Description Protocol describes multimedia session forthe purposes of session announcement, session invitation, andother forms of session related initiation. It conveys informationabout media streams in multimedia sessions to allow the recipientsof a session description to participate in that session. SessionDescription Protocol information may be transported using SAP,SIP, RTSP, MIME or HTTP.

• SIP is a control or signaling protocol used for creating, modifying,and terminating sessions between participants. These sessionsmay include multimedia conferences, telephone calls, distancelearning, or other types of multimedia distribution. SIP is a part ofthe internet multimedia protocol architecture which includes otherprotocols like RTP, SAP and SDP.



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Basic VoIP Call FlowBasic VoIP Call Flow

Station Initialization

Connection Establishment

Parameter Exchange

Data Transfer

Connection Termination



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Basic VoIP CallBasic VoIP Call

1.The caller picks up the handset. This signals an off-hook conditionto the VoIP signaling.

2. The session application issues a dial tone and waits for the caller todial a telephone number.

3. The caller dials the telephone number. The session applicationstores the dialed digits.

4. After enough digits are accumulated to match a configureddestination pattern, the telephone number is mapped to an IP host viathe dial plan mapper. The IP host has a direct connection to either thedestination telephone number or a private branch exchange (PBX) that

is responsible for completing the call to the configured destinationpattern.

5. The session application runs the session protocol to establishtransmission and reception channels for each direction over the IP network.



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Basic VoIP CallBasic VoIP Call

If Resource Reservation Protocol (RSVP) has been configured,RSVP reservations are put into effect to achieve the desired qualityof service (QoS) over the IP network.

6. The coder-decoder compression schemes (codecs) are enabled forboth ends of the connection using Real-Time Transport Protocol/User Datagram Protocol/Internet Protocol (RTP/UDP/IP) as theprotocol stack.

7. Any call-progress indications are cut through the voice path assoon as an end-to-end audio channel is established. Signalingcarried over the IP network is encapsulated in Real-Time TransportControl Protocol (RTCP) using the RTCP application- defined (APP)extension mechanism.

8. When either person hangs up the phone, RSVP reservations aretorn down (if RSVP is used) and the session ends. Each endbecomes idle, waiting for the next off-hook condition to triggeranother call setup.



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VoIP StandardsVoIP Standards

• Signaling – ITU-T Standards and Recommendation

• H.323(Packet-based multimedia communication Systems)• H.225.0 (Call Signaling protocols and media stream

packetization for packet based multimedia)• H.225.0 ( Annex G Gatekeeper to gatekeeper –interdomain- communications)

• H.245 ( Control protocol for multimedia communications)• H.235 ( Security and encryption for H- series multimedia

terminals)• H.450.x Supplementary services for multimedia



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VoIP Standards (contd)VoIP Standards (contd)

• Signaling ( contd)• H.323 Annex D Real time fax using T.38• H.323 Annex E Call connection over UDP• H.323 Annex F Single Use device• T.120 series Data protocols for multimedia conferencing

– IETF RFCs and Drafts• RFC 2543 –SIP ( Session Initiation Protocol)• RFC 2327 – SDP ( Session Description Protocol)• Internet Draft MGCP ( Media Gateway Control Protocol)• Internet Draft MEGACO protocol• RFC 1889 – RTP, RTCP



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Regulatory EnvironmentRegulatory Environment

• CALEA and Law Enforcement Issue – FBI wants the FCC to bring internet calling under provisions of

the 1994 Communications of Law Enforcement Act ( CALEA),which requires phone carriers to provide them with the directaccess to phone lines. But, in case of VoIP, the packet

information travels in digital packets which is relatively easyto encrypt or to use “secure tunnels” making theminaccessible to law enforcement.



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Benefits of VoIPBenefits of VoIP

• VoIP has extremely efficient use of bandwidth as well asflexible technology.

• Hardware and protocols for VoIP are largely off the shelf,interchangeable and developed rapidly

• VoIP can also take advantage of the same functionality thatis driving the internet, allowing providers to take advantageof the equipment at a higher level of productivity and costsavings.

• IP is the driving force for NGN( Next Generation Networks)with Convergence being an important requirement. VoIP isprobably the simplest and easiest path to convergence.



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Challenges for VoIPChallenges for VoIP

• The current IP telephony services in the current state do not offercarrier grade standards.

• Worrisome is the fact that the callers’ addresses don’t show upon emergency operators’ screens when they call 911.

• For VoIP on cable, the HSD (High Speed Data) connection isrequired, risking the caller to network and power outages.

• While the future is very promising, VoIP still has numeroustechnology challenges ahead, including integration, back officeapplications, OSS support, powering soft switches, return path

and Packet cable.



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VoIP on cdma2000VoIP on cdma2000

• Service Option 60/61 to support the VoIP connection

• Allow Service Option 33 to set up the VoIP call

• Allow smaller packet sizes on the PHY layer to allow for faster delivery of the VoIP packets

• Faster call set-up

• Header compression (1x: LLA-ROHC, HeaderRemoval, HRPD- ROHC)

• QoS support ( QoS parameter negotiation and QoSscheduling)

• Segment based framing ( for HRPD).



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Business Applications BenefitsBusiness Applications Benefits

• VoIP yields two types of benefits:

- Soft Benefits• Replacing a PBX with VoIP server may save a

company specific amount of money every year.• Soft benefits don’t necessarily save money, or if

they, do , they don’t always save an easily calculated

amount of money. But they do affect the overallbottom line in the future, like unified messaging etc.

– Hard Benefits• Clearly defined cost savings.• It is estimated that operator can reap cost savings by

leveraging the investments made for the made forthe same network to support HSD. If networkpowering along with the NIUs (Network InterfaceUnits) and related functions and equipment areexcluded then its possible to see considerable

cost savings.



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Technology Adoption ProcessTechnology Adoption Process

IntroductionIntroduction GrowthGrowth MaturityMaturity DeclineDecline

Innovators

Early

Adopters

Early

Majority

Late

MajorityLaggards

Chasm



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