5. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Some details : Analog telephones on
analog switch
twisted pair, average length 2.5 Km Line
circuit
Analog
switch
6. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Some details : Analog telephone on
digital switch
twisted pair, average length 2.5 Km Line
circuit
Digital
switch
Digital
Analog
7. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Some details : ISDN Basic Access
twisted pair, average length 2.5 Km 144Kb/s
modem
Digital
switch
144Kb/s
modem
S bus
2 * 64 Kb/s + 16 Kb/s
8. J.Tiberghien - VUBJ.Tiberghien - VUB
Conten
ts
• The traditional Telephone Network
–Overall structure
–Trunk lines
»Plesiochronous Data Hierarchy
»Synchronous Data Hierarchy
–Exchanges and signaling
–General purpose SDH networks
10. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Trunk Network (CEPT30)
Optical Fiber or Microwave Link
Digital
switch
Digital
switch
n*30*64 Kb/s
n*2048 Kb/s
11. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Trunk Network (Bell D2)
Digital
switch
Digital
switch
n*23*64 Kb/s
n* 1544 Kb/s
Optical Fiber or Microwave Link
12. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Some details : ISDN Primary Rate
Digital
switch
2048 Kb/s (CEPT30)
Optical Fiber or Microwave Link
PABX
13. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Trunk Network
Optical Fiber or Microwave Link
n*30*64 Kb/s
n*2048 Kb/s
Analog
switch
Analog
Digital
14. J.Tiberghien - VUBJ.Tiberghien - VUB
The Telephone
Network
Trunk Network
Digital
switch
Digital
switch
Optical Fiber or Microwave Link
15. J.Tiberghien - VUBJ.Tiberghien - VUB
Conten
ts
• The traditional Telephone Network
–Overall structure
–Trunk lines
»Plesiochronous Data Hierarchy
»Synchronous Data Hierarchy
–Exchanges and signaling
–General purpose SDH networks
16. J.Tiberghien - VUBJ.Tiberghien - VUB
Synchronous
Multiplexing
of almost synchronous data
flows
D C B AE
S R Q PT
F
EST D C B AR Q P01F
1 Frame
S C
fout > n * MAX(fin)
17. J.Tiberghien - VUBJ.Tiberghien - VUB
Plesiochronous Digital
Hierarchy– Each multiplexed section has its own clock
– Each level of multiplexing has its own clock
– Frame structure from multiplexed signals is not
explicitly present in the multiplexed stream
> Full demultiplexing required at each node !
18. J.Tiberghien - VUBJ.Tiberghien - VUB
Conten
ts
• The traditional Telephone Network
–Overall structure
–Trunk lines
»Plesiochronous Data Hierarchy
»Synchronous Data Hierarchy
–Exchanges and signaling
–General purpose SDH networks
19. J.Tiberghien - VUBJ.Tiberghien - VUB
Synchronous Digital
Hierarchy
STM-1 STM-1
Up to 63 channels at 2 Mb/s
– The entire trunk network has one clock
– Multiplexed stream based on 125 µS frames
– Different channels can each have their own
asynchronous clock.
– Add-drop multiplexers
26. J.Tiberghien - VUBJ.Tiberghien - VUB
Conten
ts
• The traditional Telephone Network
–Overall structure
–Trunk lines
»Plesiochronous Data Hierarchy
»Synchronous Data Hierarchy
–Exchanges and signaling
–General purpose SDH networks
27. J.Tiberghien - VUBJ.Tiberghien - VUB
Telephone
Exchange
(Conceptual Model)
Switching
Matrix
Line Circuit
Line Circuit
Line Circuit
Line Circuit
Line Circuit
Control Computer
trunk lines +
Inter-office
signaling
Register
Register
Register
Register
28. J.Tiberghien - VUBJ.Tiberghien - VUB
Signaling system
generations• SS1 - SS5 : Analog call forwarding between exchanges
• SS6 : First digital signaling system
– monolithic communications system (no layers)
– Full mesh of virtual circuits, based on 2400 b/s links
• SS7 : Signaling system for the intelligent network
– uses any digital links, satellites included
– layered, OSI inspired, network architecture
– supports "intelligent network" applications
» Non-geographic numbers (800)
» CLIP, Call forwarding, Conference calls, etc...
» Number portability
» Carrier selection
» Mobility & roaming
• IP ???
34. J.Tiberghien - VUBJ.Tiberghien - VUB
Bibliography
To know More about
Telephony
Recommended for this chapter
John BELLAMY
Digital Telephony
Second edition
John Wiley, 1991.
ISBN : 0-471-62056-4
35. J.Tiberghien - VUBJ.Tiberghien - VUB
Bibliography
To know More about
SDH
Recommended for this chapter
Mike SEXTON, Andy REID
Transmission Networking:
SONET and the Synchronous
Digital Hierarchy
Artech House, 1992.
ISBN : 0-89006-551-9