1 / 32

Digital Carrier Systems

Digital Carrier Systems. Digital carrier standard. T-carrier North America, Japan E-carrier Europe, Mexico, South America. T1 carrier system. PCM. PCM. PCM. MUX. DS-1 frame. DEMUX. PCM. PCM. PCM. DS-1 frame. each channel also refers as DS0. 125 m s. frame bit. channel #1.

suki
Download Presentation

Digital Carrier Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Digital Carrier Systems

  2. Digital carrier standard • T-carrier • North America, Japan • E-carrier • Europe, Mexico, South America

  3. T1 carrier system PCM PCM PCM MUX DS-1 frame DEMUX PCM PCM PCM

  4. DS-1 frame • each channel also refers as DS0 125 ms frame bit channel #1 channel #2 . . . . . . . channel #24 8 bit 193 bits data rate = (24x8 +1 bit)/125 ms = 1.544 Mbps

  5. T - carrier Two 1.544 Mbps DS1 channels are multiplexed into a single 3.152 Mbps DS1C channel DSI DSI Two DS1C channels are multiplexed into a single 6.312 Mbps DS2 channel DSIC DSIC Seven DS2 channels are multiplexed into a single 44.736 Mbps DS3 channel DS2 DS2 DS2 DS2 DS2 DS2 DS2 DS3 DS3 DS3 DS3 DS3 DS3 Six DS3 channels are multiplexed into a single 274.176 Mbps DS4 channel DS4

  6. 0 1 2 16 31 E1-frame 125 ms = 32 time slots = 2.048 Mbps signaling channel frame synchronization 30 voice channel+2 control channel

  7. E - carrier Thirty 64 kbps channels are multiplexed to create one 2.048 Mbps E1 channel E1 E1 E1 E1 Four E1 channels are multiplexed into a single 8.448 Mbps E2 channel E2 E2 E2 E2 Four E2 channels are multiplexed into a single 34.368 Mbps E3 channel E3 E3 E3 E3 Four E3 channels are multiplexed into a single 139.264 Mbps E4 channel E4 E4 E4 E4 Four E4 channels are multiplexed into a single 565.148 Mbps E5 channel E5

  8. Digital carrier comparison Europe E1 E2 E3 E4 E5 x31 x 4 x 4 x 4 x 4 2.048 8.448 34.368 139.264 564.992 T1 T2 T3 T4 x24 x 4 x 7 x 6 USA 64 1.544 6.312 44.736 274.176 J1 J2 J3 J4 J5 x24 x 4 x 5 x 3 x 4 1.544 6.312 32.064 97.728 397.200 Japan

  9. PDH • Digital tramsmission systems (T-carrier, E carrier) combine lower order multiplex stream to get higher bit rate • Different streams have small differences in clock signals. • Solve by adding justification bit • PDH = Plesiochronous Digital Hierachy almost synchronous

  10. PDH deficiencies (I) • Lack of flexibility • impossible to identify a lower bit rate channel from the higher-order bit stream. Extraction of 2 Mbps channel from 140 Mbps channel 34 Mbps 140 M LTE 140 M LTE 140 140 34 34 8 Mbps 34 34 8 8 2 Mbps demux the high bit rate down to the lower level remux back into higher level for onward transmission 8 8 2 2 Customer site

  11. PDH deficiencies (II) • Lack of performance • No standard for monitoring the performance of traffic channel • No management channel

  12. PDH deficiencies (III) • Lack of 慚id-Fibre meet • undefined interface specification on the line side of a line transmission PDH SDH LTE standard Network Node Interface (NNI) non standard line code and optical levels G.703 interface functional integration of MUX and LTE

  13. SDH & SONET • What is SDH/SONET ? • Standard interface developed for using in the public network • multiplexing standard for optical fiber transmission • SONET = Synchronous Optical Network • refers to the system used within the U.S. and Canada • SDH = Synchronous Digital Hierarchy • international community term (ITU-T recommendtions)

  14. SDH goals • Goals • make it possible for different carrier to interwork • unify the U.S., European and Japanese digital system • Provide a way to multiplex multiple digital signal togethers • provide support for operations, administration, and maintenace • Characteristics • use single master clock to synchronize • Bit stream can be a added or extracted directly • Basic transmission rate = 155.52 Mbps

  15. Signaling rates SONET SDH Bit rate (Mbps) STS-1/OC-1 51.84 STS-3/OC-3 STM-1 155.52 STS-9/OC-9 STM-3 466.56 STS-12/OC-12 STM-4 622.08 STS-18/OC-18 STM-6 933.12 STS-24/OC-24 STM-8 1244.16 STS-36/OC-36 STM-12 1866.24 STS-48/OC-48 STM-16 2488.32 STS = Synchronous Transport Signal OC = Optical Carrier STM = Synchronous Transport Module

  16. Synchronous Container 6 Mbps 2 Mbps 1.5 Mbps PDH signal 2 Mbps 6 Mbps 1.5 Mbps container virtual container 2 Mbps 6 Mbps 1.5 Mbps Path overhead for monitoring抯 purpose Each PDH stream is carried in an appropiate container

  17. Syncronization抯 techniques sample frame • phase offset in byte • directly access signal • signal using pointer • data begins anywhere • in frame pointer frame #1 data #1 data #1 POH #1 data #1 data #1 pointer frame #2 data #2 POH #2 data #2

  18. SONET System • consists of switches, mux and repeaters mux repeaters mux repeaters mux section section section section line line path

  19. SONET Basic Frame structure 1 frame = 810 bytes in 125ms 1 2 3 4 5 6 7 8 9 STS-1/OC1 row/column mapping 3 bytes 87 bytes Overhead : for system management information SOH = Section Overhead LOH = Line Overhead TOH = Transport Overhead Payload : user data SOH 3 bytes Payload 9 bytes LOH 6 bytes TOH

  20. SDH Basic Frame structure 1 frame = 2430 bytes in 125ms 1 2 3 4 5 6 7 8 9 STM-1 row/column mapping 9 bytes 261 bytes Overhead : for system management information (OAM) SOH = Section Overhead LOH = Line Overhead TOH = Transport Overhead Payload : user data SOH 3 bytes Payload 9 bytes LOH 6 bytes TOH

  21. STM-1 Frame 9 bytes 261 bytes SOH pointer frame #1 Payload #1 Payload #1 POH #1 LOH Payload #1 SOH Payload #1 pointer frame #2 Payload #2 POH #2 Payload #2 LOH

  22. SOH, LOH and POH transport overhead STS-1 information payload A1 A2 C1 J1 B1 E1 F1 B3 D1 D2 D3 C2 H1 H2 H3 G1 B2 K1 K2 F2 D4 D5 D6 H4 D7 D8 D9 Z3 D10 D11 D12 Z4 Z1 Z2 E2 Z5 section overhead 9 rows line overhead 87 columns 3 columns path overhead

  23. SDH mux scheme PDH Tributaries STM-1 x1 AUG AU-4 140 Mbps VC-4 C-4 x3 TU-3 VC-3 TUG-3 x3 x7 45 Mbps AU-3 C-3 VC-3 34 Mbps x1 x7 6 Mbps VC-2 TUG-2 C-2 TU-2 x3 SONET-specific 2 Mbps C-12 TU-12 VC-12 Europe-specific x4 Universal VC-11 1.5 Mbps TU-11 C-11

  24. SDH Elements Tributary Unit Tributary Unit Containers path overhead Tributary Unit Group Tributary Unit Group Virtual Containers pointer Administrative Unit Administrative Unit Tributary Unit Administrative Unit Group section overhead STM-1

  25. Containers mapping sample C2 mapping C-12 E1 fixed stuff alignment fixed stuff 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 signaling containers #bytes capacity C-11 25 1.600 C-12 34 2.176 C-2 106 6.784 C-3 672 48.384 C-4 2340 149.760

  26. Containers, VC & TU C-2 C-11 C-12 9 bytes 4 bytes 3 bytes 12 bytes VC-11 VC-12 VC-2 plus POH TU-11 TU-12 TU-2 plus pointer

  27. TU-X format 3 columns 125 ms 1 2 3 27 bytes 1728 kbps 9 rows TU-11 1 2 27 27 125 ms 4 columns 36 bytes 1 2 3 4 TU-12 9 rows 2304 kbps 1 2 36 36 12 columns 6912 kbps 125 ms 1 2 3 108 bytes 9 rows TU-2 1 2 108 108

  28. TUG-2 to VC-3 3xTU-12 4xTU-11 1xTU-2 • TUG-2 may be • 4xTU-11 • 3xTU-12 • 1xTU-2 9 bytes 12 bytes 12 bytes 12 bytes 12 bytes TUG-2 9 bytes 7xTUG2 VC-3 9 bytes 1 84 total 85 columns POH

  29. J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 J1 B3 C2 G1 F2 H4 Z3 Z4 Z5 H1 H2 H3 H1 H2 H3 H1 H2 H3 AU-3 to AUG 1 30 59 87 1 30 59 87 1 30 59 87 VC-3 plus 2 column fixed stuff 1 30 59 87 1 30 59 87 1 30 59 87 AU-3 A B C 3xAU-3 to AUG A B C A B C A B C A B C A B C A B C

  30. TUG-3 to VC-4 TUG-3 VC-3 TU-3 TU-3 PTR C-3 9 85 justification bytes 86 3xTUG-3 fixed stuff VC-4 P O H total 260 columns

  31. High order mux STM-1 #1 stream STM-1 #N STM-1 #2 MUX byte interleave Nx9 Nx261

  32. 1xOC3 and 3xoC1 • OC3 = 3xOC1 • a 155.52 Mbps carriers consisting of 3 separated OC3 carriers • OC3c = 1X155.52Mbps carriers • a data stream from single source of 155.52 Mbps • Higher-order frames also exist (e.g. OC12c). • The amount of actual user data in an OC3c stream is slighly higher thanin an OC-3 stream!

More Related