Applications
2-48 Issue 8.0 July 2002
When Release 6 of the FT-2000 OC-48 Add/Drop-Rings Terminal interworks with
Release 7.2 of the DDM-2000 OC-3 Multiplexer in subnetworks with less than 16
NEs, the same NE may serve as the TL1 GNE and the alarm GNE. However, in
subnetworks with more than 16 NEs, the NE serving as the TL1 GNE cannot
serve as the alarm GNE. The TL1 GNE and alarm GNE functions must be at
separate NEs in the subnetwork.
The FT-2000 OC-48 Add/Drop-Rings Terminal must be equipped with the OC3
Optical Interface — 1.3µm Standard Performance (OC3 [1.3 STD]) circuit pack
and the Overhead Controller — Tributary (TOHCTL) circuit pack to access the
OC-3 DCC. A single TOHCTL circuit pack can access up to eight OC-3 DCCs.
Low-speed interface slots must be assigned to an OC-3 DCC channel.
For more information about entering OC-3 DCC channel assignments for
single-ended operations, refer to Volume I, Section 8, “Administration and
Provisioning.”
The number of GNEs in a ring network is based on operational needs. For
example, to reduce the number of X.25 links between the ring network and the
operations system, one FT-2000 OC-48 Add/Drop-Rings Terminal may operate as
the GNE. If redundancy is desired, two or more FT-2000 OC-48 Add/Drop-Rings
Terminals may operate as GNEs. For more information about provisioning a GNE,
refer to Volume I, Section 8, “Administration and Provisioning.”
Synchronization Messaging 2
Synchronization messages are a method by which nodes within an FT-2000 ring
can communicate their synchronization status with other nodes in the ring. This
message set is transmitted in the S1 byte on an OC-N signal.
The messages in Table 2-2 indicate the stratum level to which the timing on an
incoming OC-N line is traceable.
Table 2-2. Synchronization Status Messages
Description
Acronym
Quality
Level
S1 bits
5678
K2 bits
123
PRS Traceable PRS 1 001 111
Synchronized - traceability unknown STU 2 000 110
Traceable Stratum 2 Holdover ST2 3 0111 101
Traceable Stratum 3 Holdover ST3 4 1010 100
Traceable SONET clock self-timed SIC 5 1100 N/A
DON’T USE for Sync DUS 7 111 000
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