363-206-295
Transmission and Synchronization Interfaces
Issue 1
December 1997
5-27
Synchronization Reconfiguration in an Access Ring
5
Figure 5-10a shows the access ring operating in its normal configuration. The
DDM-2000 Multiplexer at the CO is externally timed, and each of the other
DDM-2000 Multiplexers are line timed in a counterclockwise direction. The SQU
message is sent to indicate where timing is traceable to an external BITS and
where it is valid to be used. The timing looped back (TLB) message is sent on the
interface that is being used as the line-timing reference because a timing loop
would be created if this timing reference were used. Synchronization messaging
and automatic synchronization have both been enabled for this network.
In Figure 5-10b, a fiber has been cut between sites A and B. Immediately, the
DDM-2000 Multiplexer at site B enters holdover and sends out the internal clock
(IC) message to site C. The DDM-2000 Multiplexer at site B cannot switch to line
time from site C because it is receiving the TLB message on that interface.
Figure 5-10. Synchronization Reconfiguration — Access Ring (Sheet 1 of 3)
PRS
Traceable
BITS
DDM-2000
DDM-2000
DDM-2000
PRS
Traceable
BITS
Sync Flow
a) Before Failure
SQU
Site A
Site D
Site B
Site C
SQU
SQU
SQU
TLB
TLB
TLB
SQU
DDM-2000
DDM-2000
SQU
Site A
Site D
Site B
Site C
SQU
SQU
TLB
TLB
SQU
b) Failure Occurs,
Site B Changes Message
DDM-2000
DDM-2000
DDM-2000
STRATUM 3 if using a TG3 at site B, or IC if using a TGS.
IC
*
*
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 ...
Страница 1394: ...363 206 295 DLP 514 1 of 1 Page 1997 December 1 Issue Unused ...
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 ...