363-206-295
A SONET Overview
A-14
Issue 1
December 1997
SONET Digital Multiplexing Schemes
1
Asynchronous Multiplexing
1
Currently, fiber optic facilities are primarily used to carry DS3 signals. The DS3
signal consists of a combination of the following payload signals:
■
28 DS1s
■
14 DS1Cs
■
7 DS2s.
Typically, 28 DS1 signals are multiplexed into a DS3 signal, using an M13 format.
Refer to Figure A-8. M13 format is a process that includes bit-interleaving four
DS1 into a DS2 signal and then bit-interleaving seven DS2 signals into a DS3.
The DS3 rate is not a direct multiple of the DS1 or the DS2 rates due to the bit-
stuffing synchronization technique used in asynchronous multiplexing.
Identification of DS0s contained in any DS-
N signal, except DS1, is complex and
DS0s cannot be directly extracted. Thus, an asynchronous DS3 signal must be
demultiplexed down to the DS1 level to access and cross-connect DS0 and DS1
signals.
Another disadvantage of the M13 format is there is no end-to-end overhead
channel for use by OAM&P groups.
Figure A-8.
Asynchronous Multiplexing
DS3 X N = Line Signal
7 DS2s = 1 DS3
4 DS1s = 1 DS2
24 DS0s = 1 DS1
1 VF Circuit = 1 DS0
No End-To-End Overhead Channel
DS1 Not Observable above DS1
Bit Interleaving above DS1
Содержание DDM-2000 OC-12
Страница 1: ...363 206 295 Issue 1 December 1997 DDM 2000 OC 12 Multiplexer Release 7 0 User Service Manual Volume I ...
Страница 37: ...Tables xxxviii Issue 1 December 1997 A A SONET Overview A 1 SONET Payloads A 18 A 2 SONET Transport Rates A 19 ...
Страница 506: ...INS PROG 8 of 8 Page INS PROG COMMANDS RELATED rtrv eqpt rtrv ne OC 12 DDM 2000 1997 December 1 Issue 11 89 ...
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Страница 766: ... Ctl T TOGGLE 2 of 2 Page Ctl T TOGGLE COMMANDS RELATED logout rlgn OC 12 DDM 2000 1997 December 1 Issue 11 349 ...
Страница 847: ...Multiplexer OC 12 DDM 2000 7 Release TARP TOP Manual User Service II Volume 363 206 295 1 Issue 1997 December ...
Страница 867: ...363 206 295 TOP Maintenance and Operation BLANK LEFT INTENTIONALLY PAGE THIS 12 1997 December 1 Issue ...
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Страница 1565: ...363 206 295 DLP 543 6 of 5 Page 1997 December 1 Issue Network Broadcast Video of Test Transmission 2 Figure ...
Страница 1566: ...DLP 543 363 206 295 1997 December 1 Issue 6 of 6 Page Network Ring Virtual ATM of Test Transmission 3 Figure ...