migration en ngn

8/2/2019 Migration en NGN

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After this short presentation of the NGN network, the next step in our project is to propose a

solution to migrate the PSTN network that we have designed to NGNC4 network that we saw

previously where local exchanges are left unchanged while the transit layer is replaced by

Softswitches and media gateways (see the figure below).

Our solution should include the following points: architecture, migration procedure,

Softswitches, MGM and MSAN dimensioning, required transmission capacity (estimation), cost

and financial study.

As data input, we have 20% of residential subscribers and 50% of business subscribers in the big

cities, are internet subscribers (128 kbps and 512 kbps respectively).

We are going to consider the same design of our PSTN network with the following changes:

All the transit exchanges are going to be replaced with one softswitch (with a maximumcapacity of 800 000 subscribers) since the total number of subscribers is 429 800.


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In the following table, we have calculated for each area the number of voice subscribersonly and the number of subscribers that are internet subscribers as well.

Area sub. Voice only sub. Voice+ internet

A 75600 30400

C 35800 14400E 56200 22400

B 42200 14400

D 63600 25600

F 38000 11200

total 311400 118400

For the migration of the PSTN network to a NGN network class 4, we will keep on the local

exchanges and RSU that we have chosen, but these local exchanges will be considered only for

the subscribers that are not internet subscribers, by doing the calculation of the CP load for thebig city A, we got: CP load%=57.08%, then the whole area of A having the CP load less

than 80%, will need only one local exchange A.

These local exchanges are going to be connected to the softswitch via a certain number of media

gateways. For the internet subscribers in the big cities, we will use a certain number of MSAN

that will be defined in the next table. We will use the whole ports as xDSL ports, this means

having 480 ports in each MSAN. These MSANs will be connected to the softswitch.

The following tables show the numbers of residential and business subscribers that are internet

subscribers as well as the required capacity in each big city, the number of MSAN and of media

gateways that are required.

To fill the tables, we have used the following points:

Number of residential internet subscribers=0.2*nber of residential subscribers. Number of business internet subscribers=0.5*nber of business subscribers. 128 kbps is given as a speed for residential subscribers, by adding 40 bytes for IP

packets, 38 bytes for Ethernet and 160*2 bytes for G.711 coding (during 20ms), we will

get:8*(160*2+40+38)/20ms= 159.2kbps=0.1592Mbps.

The same calculation will be done for 512 kbps, we will obtain than:

8*(160*8+40+38)/20ms=543.2kbps= 0.5432Mbps.

Then the required capacity will be given by:

0.1592*number of residential internet subscribers in the big city+0.5432*number of

business internet subscribers in the big city (Mbps).

The number of MSAN is determined by dividing the number of internet subscribers by480 (ports) and rounding up the result.


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The number of media gateway is determined by dividing the number of subscribers (onlyvoice) in each area by 30000 ( maximum capacity of a MGW) and rounding up the result.

City

Residential

subscribers Business subscribers

res. Internet

sub.

bus. Internet

sub.

A 57000 38000 11400 19000C 27000 18000 5400 9000

E 42000 28000 8400 14000

B 27000 18000 5400 9000

D 48000 32000 9600 16000

F 21000 14000 4200 7000

Total 222000 148000 44400 74000

Internet

subscribers

required capacity

(Mbps) MSAN

media

gateway Softswitch

30400 29716 64 3

14400 14076 30 2

22400 21896 47 2

14400 14076 30 2

25600 25024 54 3

11200 10948 24 2

118400 115736 249 14 1


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We will sketch only a part of the migrated PSTN network that will look like to something like

that:

MSAN

Financial study:In this part, we are going to follow the same step as the financial study in the previous section:

1. Network cost: The cost of the softswitch is given by 5MU/line=5*number of subscribers

=5*429 800=2 149 000MU.

The cost of the local exchanges and RSU is given by 20MU/line=20*number of voicesubscribers= 20*311 400=6 228 000MU.

The cost of the MSAN is given by 20MU/port=20*number of internet subscribers=20*118 400=2 368 000MU.

The cost of the MGW is given by 3MU/line= 3*number of voice subscribers=934200MU.

city

RSU

LE

MGW

softswitch

IP/MPLS network


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The the total will be= 11 679 200MU.

The cost of the junctions and loops is given for 44 PDH links of 34Mbps and 24 PDHlinks of 139 Mbps used= 44*17*200+24*69.5*200=483 200MU.

N.B: since we used in this migration only one local exchange A, then the number of PDH

of each kind had changed.Actually, the transmission between LE A and the RSU will be like this:

25E1 19 11 6

9E1

The cost of FO&MW= 483200/2=241 600MU. The local loop price=0.4(241 600+483 200+11 679 200)=0.4*12 404 000=4 961 600MU. The IN platform cost=0.6*(12404000+4961600)=0.6*17 365 600=10 419 360MU. The TMN cost=0.7*(10 419 360+17 365 600)=0.7*27 784 960=19 449 472 MU. The total cost of the network=27 784 960+19 449 472=47 234 432MU.2. Network Incomes : We are going to consider the same incomes that we have obtained in the section 5 of the

project: 1.015336349*10^10+17 178 480S+480 205I

in addition, we should consider the internet income.We will consider that monthly internet subscription is given by 2S for 128kbps and 6S

for 512kbps.

Then the internet income after these four years will be:

[2S*residential internet subscribers+6S*business internet subscribers](0.4+0.7+0.9+1)=[2S*44 400+6S*74000]*3=1 598 400S

Then the total revenues are=1.015336349*10^10M+17 178 480S+480 205I +1 598 400S

By replacing with S=103M and I=2060M,

c 1 c2

a 1 a2

mbfA


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Then the total incomes will be=1.521545093*10^10 M that must be equal to the

network cost 47 234 432MU.

M=3.1044*10^-3 MU.S=0.3197532 MU.

I=6.395064 MU.

We can deduce from the calculated value of M, that by migrating the PSTN network to

NGN class 4, we can reduce the tariffs and at the same moment provide new services for

the subscribers and get new subscribers as well.

Conclusion

Migration from PSTN to NGN is an absolute prerequisite for all telecom service providers to

differentiate, grow and generate new revenues. Large scale deployment of innovative

applications, with easy-to-use service portals is possible through NGN only.

Migration of PSTN to NGN is operator-specific and should be completed in a phased manner.Simply replacing the existing network will not generate additional revenue until the new

services, which can be provided by NGN are provided to the subscribers.

Migration to NGN can also retain the existing customers by offering new services resulting in

increase in subscriber base and ARPU.

migration en ngn

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