363-206-295
Maintenance Description
9-18
Issue 1
December 1997
In Figure 9-5(a), transmitted optical signals in each direction are permanently
bridged to the service and protection fibers. The same signal is transmitted on
both fibers. Each service and protection fiber and its associated OLIU are
monitored as a set. The fiber/OLIU set selected by the receiving location is the
active set and the ACTIVE LED, which in Figure 9-5(a) is on the service OLIU
circuit packs, is lit. The fiber/OLIU set not selected is the standby set, and the
ACTIVE LED on its corresponding OLIU is not lighted.
Contrary to other transmission circuit packs, ACTIVE LEDs on both OLIUs may be
lit at the same time on the same shelf. For example, in Figure 9-5(b) the receive
fiber going to location C has been cut. Location C selects the protection fiber/
OLIU set as active, resulting in the lighting of ACTIVE LEDs on both the OLIUs at
location C. Location A did not switch to its protection set but continues to remain
on the service set. This example illustrates the SONET standard of unidirectional
APS. Since each location sends APS information to the other end, both ACTIVE
LEDs on the OLIUs at location A are also lit.
After the cut service fiber is repaired, location C will not switch back (revert) and
select the service set as its active fiber/OLIU set. This example, Figure 9-5(c),
illustrates the SONET standard of nonrevertive APS.
Figure 9-5(d) and Figure 9-5(e) illustrate a second fiber failure and the resulting
changes to the active OLIUs, thus showing that both protection sets could be
active and carrying service.
APS Initiation Criteria
9
The APS is initiated by signal fail and signal degrade conditions on the received
optical signal. The BER of the received optical signal is calculated from violations
in the SONET line overhead B2 parity bytes. Signal fail is declared for:
— Incoming OC-12 LOS
— OC-12 LOF
— OC-12 Line AIS
— OC-12 BER exceeding 10
-3
.
An OC-12 BER exceeding a provisionable 10
-5
to 10
-9
threshold causes the signal
degrade condition. An APS is completed within 60 milliseconds of the beginning of
a hard failure such as a fiber cut.
The DDM-2000 OC-12 Multiplexer APS is "span independent." In multispan
applications, such as hubbing, an automatic or manual protection switch on one
span does not cause a protection switch on any other span.
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 ...
Страница 528: ...RTRV ATTR ALM 2 of 2 Page RTRV ATTR ALM COMMANDS RELATED set attr alm OC 12 DDM 2000 1997 December 1 Issue 11 111 ...
Страница 565: ...RTRV OC3 3 of 3 Page RTRV OC3 COMMANDS RELATED rtrv sync 11 148 1997 December 1 Issue OC 12 DDM 2000 ...
Страница 664: ...SET FEAT 3 of 3 Page SET FEAT COMMANDS RELATED rtrv feat OC 12 DDM 2000 1997 December 1 Issue 11 247 ...
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 ...
Страница 1145: ...Order Circuit 363 206 295 NTP 029 1 of 1 Page 1997 December 1 Issue Unused LISTED ORDER IN BELOW ITEMS DO TO GO DETAILS FOR ...
Страница 1146: ...Order Circuit 363 206 295 NTP 030 1 of 1 Page 1997 December 1 Issue Unused LISTED ORDER IN BELOW ITEMS DO TO GO DETAILS FOR ...
Страница 1182: ...Turnup System 363 206 295 NTP 033 1 of 1 Page 1997 December 1 Issue Unused LISTED ORDER IN BELOW ITEMS DO TO GO DETAILS FOR ...
Страница 1243: ...Clearing Trouble 363 206 295 TAP 107 1 of 1 Page 1997 December 1 Issue Unused ...
Страница 1393: ...363 206 295 DLP 513 1 of 1 Page 1997 December 1 Issue Unused ...
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Страница 1456: ...363 206 295 DLP 523 7 of 7 Page 1997 December 1 Issue OC 12 via Access Broadcast Video for Cross connections of Example 4 Figure ...
Страница 1465: ...DLP 525 363 206 295 1997 December 1 Issue 6 of 2 Page Schematic Ring Virtual ATM Sample 1 Figure ...
Страница 1469: ...DLP 525 363 206 295 1997 December 1 Issue 6 of 6 Page Ring Virtual ATM OC 12 DDM 2000 for Cross connections of Example 4 Figure ...
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 ...