Md. Shahidul Alam*
1. Introduction: A glimpse of the past
1.1
Manual/Analogue Era: Bangladesh Telecommunications Company Ltd (BTCL)
inherited telecommunication system from the then British India through a series
of transformation. Telegraph system was first introduced in Bengal in 1853 by
the East India Company of England, the then colonial ruler of Bengal. Following
the telegraph system different telecommunication services were introduced one
after another. During independence from British India, the telecommunication
system of the then East Pakistan (also in Indian subcontinent) was manual.
Manual Magneto Exchange was the main exchange for voice communication and
telegraph system was the main source of data communication using Morse code.
Over head Physical lines were the main transmission media. Since then there was
a lot technological change in the field of telecommunication. After Magneto
exchange another manual exchange Central Battery (CB) Exchange was introduced.
In magneto and Central Battery manual exchanges a call set up between two
persons was done with the help of operators i.e., when someone intends to talk
to another one he had to rotate the handle of magneto phone or off hook
receiver of telephone set belonging to Central Battery system to notify the
operators and he gave the telephone number of his intended person to the
operator. For long distance call nation and International calls some times more
than two operators were involved to connect a call. The operators then connect both caller &
called party through a Switch Board. After manual system Electromechanical system
such as F1, Cross bar and EMD system were installed and worked until mid 80s of
last Century in BTCL (the then BTTB) network. Though these Electromechanical
Exchanges were automatic, except voice communication, there was no Value Added
Services (VAS).
1.2 Automatic/Digital Era: Bangladesh Telecommunications
Company Ltd entered into the era of digital telecommunication through the
introduction of NEC's NEAX 61K/M Model digital Trunk Automatic Exchanges(TAX)
in Dhaka, Chittagong, Bogra and Khulna and 0ne
International Trunk Exchange (ITX) in Dhaka. With the introduction of
digital TAXs and ITX, subscribers themselves could make long distance national
and international call by direct dialing using local area code and overseas
Telephone number without the help of operator. With the aim of total
digitization, the 1st digital telephone exchange (class 5 service) of the
country was introduced in Dhaka during the late 80s with NEC's NEAX 61E. These
digital exchanges were deployed with some Value Added services. Later in 90s
Digital exchanges [E-10, Alcatel, France] were installed in Dhaka, Chittagong,
Khulna, Rajshahi and Sylhet with ISDN facilities. From then onwards different
networks consist of switches of many vendors such as Ericsson, Nortel, Shanghai
Bell, Huawei, ZTE etc were installed throughout the country. At present
telecommunication network of Dhaka metro city is a non-homogeneous mixture of
digital exchanges of various generations and techniques.
1.3
IP/Packet based communication Era:
The technology applied in the telecommunication systems is changing
rapidly. The customer now demands all types of entertainment and communication
services from a single delivery point. As the Circuit-switched exchange can’t
meet this integration requirement, BTCL has no choice but adopting IP based NGN
technology to cope with the present demand and to modernize the telecommunication
system by undertaking a project named ‘Replacement
of Old Digital Telephone System of Dhaka city’ commonly known as 171 KL
Project.
*General Manager, BTCL
** Divisional Engineer, BTCL
2.
Aim/Objective of the Project:
All [total 747 as of now] of the
telephone exchanges [Class 5] of BTCL that are operational now based on circuit-switching
technology and a huge amount of copper cables are required to connect each
customer. In this project, Optical fiber will be installed from exchange [Soft-
switch or a node of it: there will be 2 soft-switches one at SBN and another at
Ramna with 5 other nodes at Gulshan, Uttara, Mirpur, Nilkhet & Mogbazar] to
AGW [Access Gateway: A small exchange which will be installed near customer’s
house at rented/outdoor premises] to reduce the application of copper cable. In
some places optical fiber will be installed up to customers’ homes [FTTH] or
buildings [FTTB]. With the application of optical fiber at the distribution
level, a huge bandwidth [Minimum 20 Mbps per customer for the case of FTTB and
even more in the case of FTTH] is possible to offer each customer with a range
of diversified value added services like IPTV, VoD, Online Gaming etc. The
project has chosen Mirpur DOHS as its first FTTH site and the implementation
work is going on. Upon completion of this site, other areas of Dhaka city can
be considered. FTTB will be implemented some important areas like part of
Dhanmondi, Gulshan, Nilkhet, Mogbazar, Uttara and Ramna. AGW will be installed throughout
Dhaka city.
3. Project Details :Facilities/Services
to be provided by this project—
This project is the 1st of its kind
taken by BTCL to provide multiple services like voice, video & data by a
pair of wires from a single delivery point. This NGN based solution will make
the new system cheaper and more versatile. It will also reduce copper cable
portion of customer lines and hence will reduce the occurrence of regular
faults. A huge potential/hidden demand for telephones and different value added
services presently exist in the telecom sector and BTCL can exploit it upon
completion of this project.
3.1
AGW, LAN Switch, FTTH/FTTB
Equipment/Terminals:
Main items
|
Quantity
|
Total AGWs
|
196
[Inside BTCL exchanges: 52,
rented indoor: 81, Outdoor:63]
POTS only [80%] and
POTS+ADSL2plus [20%]
|
Total Type-1 LAN Switch
|
2
[SBN and Ramna for
interconnection with other network devices]
|
Total Type-2 LAN Switch
|
6
[installed at Gulshan,
Mogbazar, Uttara, Nilkhet, Mirpur and DoHS, Mirpur site for interconnection
with other network devices]
|
Total Type-3 LAN Switch
|
35
[installed at 35 sites where
a demand of Internet bandwidth exists]
|
Total GPON OLT sites
|
7
[SBN, Ramna, Gulshan,
Mogbazar, Uttara, Mirpur DoHS and Nilkhet]
|
Total GPON Ports
|
376
[The capacity of each port
is 2.5Gbps down & 1.25Gbps up link and each OFC line can be splitted up to
8x8=64 lines]
|
Total FTTH/FTTB
|
FTTH [4,500 Homes only for
Mirpur DoHS area],
FTTB [1,600 Buildings
through Dhaka city]
|
Total MDUs
[To connect buildings]
|
1,600
950
nos of capacity [24 POTS+24 FE] & 650 nos of capacity [16 POTS+16 FE]
|
Total SBUs
[To connect small business
units]
|
25
Each SBU’s capacity is [8POTS+4FE+8E1]
|
Total ONTs
[To connect each home]
|
4,500
Each ONT’s capacity is [2
POTS+4FE]
|
Total ONT Batteries
|
500
[out of total 4500 ONTS, 500 will have
batteries]
|
Total UPS for MDU
|
150
[out of total 1600 MDUs,
150 will have UPS]
|
3.2 Quantity of Total POTS Lines, ADSL2+ Lines and
FE Ports:
Technology used
|
POTS Line
|
ADSL2+ line
|
FE port
|
||||||||||
Through AGW
|
196,672
|
35,840
|
0
|
||||||||||
Through MDU [FTTB]
|
33,200
|
0
|
33,200
|
||||||||||
Through SBU
|
200
|
0
|
100
|
||||||||||
Through ONT [FTTH]
|
9,000
|
0
|
18,000
|
||||||||||
Total
|
239,072
|
35,840
|
51,300
|
||||||||||
3.3
Capacity & quantity of AGWs
exchange-wise:
|
|||||||||||||
Sites
|
Qty of AGW Cabinets
|
Line/Cabinet
|
Total Line/site
|
MDF Capacity/site
|
No of cards
|
||||||||
POTS
|
ADSL
|
POTS
|
ADSL
|
POTS
|
ADSL
|
||||||||
AGW, TYPE-1
|
|||||||||||||
Sher-e-Bangla
Nagar
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
21*64+8*32
|
|||||
Ramna
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
Nilkhet
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
Moghbazar
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
Mirpur
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
Gulshan
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
Uttara
|
5
|
1,600
|
256
|
8,000
|
1,280
|
8,000
|
1,280
|
||||||
TOTAL
for Type-1
|
35
|
56,000
|
8,960
|
56,000
|
8,960
|
||||||||
AGW, TYPE-2
|
|||||||||||||
Different
Rented Place (with LAN Switch)
|
35
|
1,216
|
192
|
42,560
|
6,720
|
56,000
|
8,960
|
16*64+6*32 expandable upto
21*64+8*32
|
|||||
Total
for type-2
|
35
|
42,560
|
6,720
|
56,000
|
8,960
|
||||||||
AGW, TYPE-3
|
|||||||||||||
Chawkbazar
|
6
|
1,664
|
192
|
9,984
|
1,152
|
9,984
|
1,152
|
23*64+6*32
|
|||||
Babubazar
|
6
|
1,664
|
192
|
9,984
|
1,152
|
9,984
|
1,152
|
||||||
TOTAL
for Type-3
|
12
|
19,968
|
2,304
|
19,968
|
2,304
|
||||||||
AGW, TYPE-4
|
|||||||||||||
Lalbagh
|
1
|
1,216
|
192
|
1,216
|
192
|
1,600
|
256
|
16*64+6*32
expandable upto 21*64+8*32
|
|||||
Khilgaon
|
2
|
1,216
|
192
|
2,432
|
384
|
3,200
|
512
|
||||||
Goran
|
1
|
1,216
|
192
|
1,216
|
192
|
1,600
|
256
|
||||||
Mohanagar
|
1
|
1,216
|
192
|
1,216
|
192
|
1,600
|
256
|
||||||
Different
Rented Place (without LAN Switch)
|
46
|
1,216
|
192
|
55,936
|
8,832
|
73,600
|
11,776
|
||||||
TOTAL
for Type-4
|
51
|
62,016
|
9,792
|
81,600
|
13,056
|
||||||||
AGW, TYPE-5 (Outdoor Type)
|
|||||||||||||
Different
Sites
|
63
|
256
|
128
|
16,128
|
8,064
|
30,240
|
14,112
|
2*64+4*32 expandable upto
4*64+7*32
|
|||||
TOTAL
for Type-5
|
63
|
16,128
|
8,064
|
30,240
|
14,112
|
||||||||
Grand
Total for AGWs
|
196
|
196,672
|
35,840
|
243,808
|
47,392
|
||||||||
4.
Conclusion:
The implementation
period for this project is September 2009 to June 2014. The OSP implementation
work is difficult in Dhaka city and renting of houses is costly. Getting
electricity connection for AGWs at rented premises is also very troublesome.
So for the future projects to be taken by
BTCL, we recommend the following:
a) The
Access network will be an integral part of the GPON system. The GPON OLT will
have different types of interface boards which are capable of providing
different types of services like POTS, ADSL, VDSL, FTTB, FTTH, FTTC etc. The
customer end device namely MDU [for FTTB, POTS, ADSL and VDSL services], ONT
[for FTTH] and SBU [for small business units] will be connected with GPON OLT
by a pair of optical fibers.
b) ONT
and SBU will be placed inside the customer’s home/office while the MDUs will be
installed inside any building. No renting of houses & no commercial electricity
connection will be necessary but an arrangement with the building owner will be
required. From MDU copper cable networks will be implemented but within a very
small area [for POTS, ADSL & VDSL only telephone cables and for POTS and
FEs both telephone and Cat5 cable up to customer will be needed].
c) Before
implementing the cable [both OFC & copper] networks, a comprehensive survey
of existing cables will have to be done by the vendors/contractors to utilize
the existing cables and to avoid repetition of works.
d) There
should be intelligent fault diagnosis system to help locate faults quickly and
accurately for all the new and existing OFC and copper cable networks.
Automated messages to the maintenance staffs for any occurrence of such faults
should have to be sent immediately.
e)
At BTCL Exchange [CO], we need to arrange only
GPON OLT.
Type-1. GPON OLT interface (Optical) broad
Type-2. GE Ethernet interface (optical)
Type-3. STM-1 interface cards (Optical)
Type-4. Electrical E1 boards
Type-5. POTS
only or POTS + ADSL [combo cards]
or POTS +VDSL [combo cards] cards.
f) Outside
BTCL Exchanges we need only small cabinets:
From GPON OLT to customer end:
Splitters may or may not be used [for Type-1service boards splitters may be
used and for Type-2 service boards no splitting will be used].
Consists: Mainly MDU which will
need a cabinet box completed with battery, MDF and
Splitter & splice tray
(where necessary)
Option 1: functions like AGW
coming from type-2 cards of GPON OLT without splitting
POTS+VDSL [Combo] cards
POTS+ADSL [Combo] cards
POTS Only cards
Option 2: functions like FTTB
coming from type-1 cards of GPON OLT with splitting
Option 3: functions like FTTH
coming from type-1 cards of GPON OLT with splitting
Option 4: functions like Small
Business Unit (SBU) to feed enterprise customers
g)
Service
to be offered to the customers:
1. POTS
only.
2. POTS+
ADSL2+ [internet speed up to 2 Mbps or even more]
3. POTS+VDSL [Speed up to 10 Mbps]
4. POTS+FE
[Speed up to 20 Mbps] à FTTB
5. multiple
POTS+ multiple FEs [speed up to 78 Mbps] à FTTH
6. multiple
POTS+ multiple FEs + multiple E1s à SBU for enterprise customers.
[For serial 3
to 6 value added services like IPTV, VoD and On Line Gaming shall be offered]
7. Other services like VPN [point to point
& point to multi point], Leased line internet of any band
width will also be offered to customers
by utilizing LAN Switch already placed at different places
of Dhaka city.
--------
visitor management system dealers in pune
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