Transition from PSTN to NGN: Possible Scenarios

Transcription

1 Transition from PSTN to NGN: Possible Scenarios ITU-D Regional Development Forum for the EUR and CIS Region NGN and Broadband, Opportunities and Challenges Chisinau, Moldova, August 2009 NGN Next Generation Network ITU-T Recommendation Y.2001: The NGN (Next Generation Network) is conceived as a concrete implementation of the GII (Global Information Infrastructure) NGN is a packet-based network able to provide telecommunication services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent from underlying transport related technologies. It enables unfettered access for users to networks and to competing service providers and/or services of their choice. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users. 1

2 Incentives of transition to NGN (1) Historical aspects of the telecom market evolution Voice services were a milking cow" for the telecom Operators in XX century. In XXI century situation changes, although voice services remain important source of revenue. Source: B. Jacobs. Economics of NGN deployment scenarios: discussions of migration strategies for voice carriers. How much is subscriber eager to pay for broadband access in Russia, per month: $10 31,2%; $20 43,8%; $30 12,5%; $40 6,2%; $50 6,2%; >$50 0%. Source: Inform Courier Sviaz, October 2008 (in Russian). Incentives of transition to NGN (2) Economical aspects of the telecommunication Operator s service Type of Operator s costs Today Change Tomorrow Capital investments share 35% 1,25 43,75% Operational costs share 65% 0,5 32,5% Total volume of costs 100% 76,25% Source: P.K. Edholm. Networks transformation: correlation of the resources limitation and system complexity. Mobile telecommunications, 2005, 8. 2

3 Incentives of transition to NGN (3) Aspects of the traffic change Incentives of transition to NGN (4) Aspects of the equipment aging in the telecommunication networks 3

4 Incentives of transition to NGN (5) Aspects of integration and convergence Specifics of the access networks modernization Changes in the access network Tone frequency channel (single-wire circuit) Tone frequency channel (two-wire circuit).. xdsl FTTx BWA Broadband paths XX century XXI century Time 4

5 Statement of the transition to NGN problem (1) PSTN Operators should find viable strategy of the transition to NGN, which provides protection of investments in circuitswitched technology. Source: B. Jacobs. Economics of NGN deployment scenarios: discussions of migration strategies for voice carriers. It is necessary to combine PSTN s quality of service and IP technologies economical efficiency! Statement of the transition to NGN problem (2) 5

6 Quality of service indices for the NGN In the table below QoS indices for six classes are given. These values are defined for the following indices: IPTD IP packet transfer delay, IPDV IP packet delay variation, IPLR IP packet loss rate, IPER IP packet error rate. Source: ITU-T Recommendation Y QoS class IPTD IPDV IPLR IPER ms 50 ms ms 50 ms ms U ms U s U U U U U IPDV definition F(t) - distribution function of the packets delay 1,0 =0.001 IPDV = T T MAX MIN 0 Time T MIN T MAX 6

7 QoS aspect: time irreversibility Speech quality impairment compensation in CS networks: Elaboration of the speech signal processing algorithms; Signal amplification (when necessary). Speech quality impairment compensation in IP networks under condition of the excessive packet exchange delay: Impossible in principle!!! QoS aspects: ISO model (1) 7

8 QoS aspects: ISO model (2) Z normalized quantity of the IP packet mean delay between UNIs, T propagation time between UNIs, N acceptable number of NGN domains between two terminals: N Z X T + Y Modernization principles of the PSTN as a whole 8

9 Scenarios and variants of the transition to NGN Pragmatic approach towards NGN construction Initial stage t : K ( t ) << M ( t ); time t : K ( t ) < M ( t ); 0 j 0 j 0 1 j 1 j 1 dismantling CO ( time t ) : K ( t ) = M ( t ) + K ( t ). 2 j 2 j 2 j 2 9

10 Two variants of the transition to NGN MSAN1 MSAN1 V5.2 V5.2 MSAN2 CO2 CO1 MSAN2 CO2 CO1 V5.2 V5.2 CO3 CO3 V5.2 V5.2 MSAN3 MSAN3 MSAN1 ADSL MSAN21 VDSL R1 MSAN2 MSAN3 MSAN22 MSAN23 MSAN24 R2 Served area of the dismantled CO3 MSAN25 MSAN11 a) Variant of the NGN construction without change of the existing network b) Variant of the NGN construction with changes according to preconceived plan Modernization of the urban network with transit exchanges (1) 10

11 Modernization of the urban network with transit exchanges (2) MSAN12 (62) MSAN63 MSAN51 MSAN53 MSAN52 MSAN54 MSAN11 (61) MSAN55 IP network with QoS R1 R6 R2 R5 R3 R4 CR2 CR1 MSAN56 MSAN35 MSAN13 (21) MSAN22 MSAN24 MSAN31 MSAN33 MSAN23 MSAN34 MSAN25 MSAN32 Modernization of the urban network with transit exchanges (3) 11

12 Modernization of the urban network with transit exchanges (4) IP-PBX2 MSAN12 MSAN52 MSAN11 TX1o R5 R1 R2 IP network with QoS MSAN22 R3 TX2o MSAN23 IP-PBX1 MSAN24 MSAN53 TX1i TX2i MSAN25 CO13 Toll exchange CR2 CO23 IP-PBX3 Modernization of the urban network with transit exchanges (5) IP-PBX2 MSAN12 (62) MSAN63 MSAN51 MSAN52 MSAN54 MSAN53 MSAN11 (61) MSAN55 IP network with QoS R1 R6 R2 R5 R3 R4 CR2 CR1 MSAN56 MSAN33 MSAN35 MSAN13 (21) MSAN22 MSAN24 MSAN31 IP-PBX3 MSAN23 MSAN34 IP-PBX1 MSAN25 MSAN32 12

13 Risk estimation for PSTN Operator Development of the PSTN without transition to NGN Mean value Variation coefficient Construction of the NGN as overlaid network Mean value Variation coefficient Pragmatic approach towards NGN construction Mean value Variation coefficient Poll results acquired by means of Delphi method Economics and risks: typical NPV curves NPV (Net present value) R III Payback period R II R I Time T I T II T MAX T III I I I II t I I MAX t II Event X I III t III 13

14 Transition from PSTN to NGN: Possible Scenarios Thank you! Nikolay Sokolov, Saint-Petersburg 14