363-206-295
Transmission and Synchronization Interfaces
Issue 1
December 1997
5-21
Synchronization Provisioning Integrity
5
A welcome side feature of synchronization messaging is that it helps prevent
provisioning errors. Provisioned timing loops on the DDM-2000 Multiplexers will be
quickly detected through the synchronization messaging algorithm and prevented
by forcing a shelf into holdover. The system can then be reprovisioned correctly.
Feature Details and Options
5
As mentioned previously, SONET synchronization messaging is used to
communicate the quality of the subnetwork timing throughout the subnetwork. This
is done using bits 1-3 of the K2 byte found in the SONET overhead. In OC-12
Release 5.1 and later releases, synchronization messaging can also be done using
bits 5-8 of the S1 byte in the SONET overhead. If a DDM-2000 OC-12 system is
deriving timing from a given OC-N interface, and synchronization messaging is
enabled on that interface (Kbyte messages and Sbyte messages in OC-12 Release
5.1 and later are provisioned using the
set-ocn
command), the system interprets
the received message to determine its internal timing status. The system also
determines the state of the DS1 output, if the DS1 output is enabled. The
DDM-2000 OC-12 system also transmits over the particular OC-N interface and all
other OC-N interfaces that are enabled for synchronization messaging, the
appropriate message indicating the quality of its timing and its active timing mode.
Table 5-3 and Table 5-4 list the associated internal timing status and DS1 Output
states that are associated with synchronization messages received from the OC-N
interface when synchronization messaging is enabled. The tables lists the
messages from low to high quality.
Table 5-3.
Synchronization Messages using K2 Byte
Received Message
Active Timing Mode
∗
Default
DS1 Output State
Quality
Level
Don't Use
Holdover
AIS
7
Timing Looped Back (TLB)
Holdover
AIS
7
Stratum 4 †
Holdover
AIS
6
Internal Clock (IC)
OK to use
AIS
5
Internal Clock (IC) (w/TG3)
Holdover
AIS
5
Stratum 3 †‡
OK to use
Good
4
Stratum 2 †
OK to use
Good
3
Sync Quality Unknown (SQU)
OK to use
Good
2
Stratum 1 †
OK to use
Good
1
*
This column applies only when provisioned for line timing mode.
†
Presently, DDM-2000 OC-12 Multiplexers cannot generate these messages, but they
could be retransmitted and supported for autoreconfiguration if any of these are
received by DDM-2000 OC-12 Multiplexer.
‡
The TG3 circuit pack can generate a stratum 3 message.
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 ...