363-206-285
Administration and Provisioning
Issue 3 June 2001
8-55
For this example, the cross-connections are:
ent-crs-sts1:m-1,b:cct=dc,ring=m2—at CO 1 (upper NE)
ent-crs-sts1:m-1,b:cct=dc,ring=m1—at CO 2 (upper NE)
ent-crs-sts1:m-1,m-1—at CO 3 and CO 5 (pass-through)
ent-crs-sts1:b,m-1—at CO 4 (two-way drop).
The continued signal at CO 1 must be assigned to Ring 2 ("m2"), and the
continued signal at CO 2 must be assigned to Ring 1 ("m1").
8. Cross-connections supporting DS3 services are STS-1 cross-connections.
Cross-connections supporting DS1 services may be either STS-1 or VT1.5
cross-connections. VT1.5 drop and continue services use the same
procedure except that the addresses and channels used are VT. The
interface between the two rings at the drop and continue nodes is still the
STS1E circuit pack, which can support VT1.5 cross-connections as well as
STS-1 cross-connections. See the TOP section of this manual (Volume II)
for procedures.
OC-3/OC-12 VT1.5 Path Switched Ring (0x1) Single
Homing 8
Figure 8-6 shows an example of an OC-12 VT1.5 path switched ring (0x1) single
homing application. The figure is placed after the example explanation and can be
removed for reference.
The DDM-2000 OC-12 ring supports 0x1 OC-3/IS-3 interfaces in its function unit
slots. These interfaces must be provisioned as 0x1. Signals pass through the
DDM-2000 OC-12 transport ring and exit to the DDM-2000 OC-3 ring. OC-12
function unit slot FN(x)-1 is connected to OC-3 main-1, and OC-12 function unit
slot FN(x)-2 is connected to OC-3 main-2. Switching is not done on the
DDM-2000 OC-12 Multiplexer on these lines or paths on these lines; rather VT1.5
or STS-1 level path switching is done on the DDM-2000 OC-3 Multiplexer. This
allows DDM-2000 OC-3 nodes running ring software to interface with DDM-2000
nodes of an OC-12 ring in such a way as to provide ring-on-ring architecture.
Each OC-3 ring so supported occupies up to three STS-1 time slots on the OC-12
ring. Each OC-12 node can provision the same STS-1 time slots as other OC-12
nodes to drop to the OC-3 shelf (to share STS-1s among several OC-3 shelves)
or the OC-12 node can provision different STS-1s at different sites. When 0x1 is
used, the OC-12 ring passes the contents of these STS-1 time slots between the
low-speed OC-3/IS-3 lines and OC-12 high-speed lines without terminating them
or performing any path protection switching on them. Up to four OC-3 rings can be
supported in this fashion by an OC-12 ring to maximize the OC-12 bandwidth
utilization. This allows access to any and all VT1.5 signals at an OC-12 site. Since
the high-speed signals from the OC-3 ring(s) are sent as two copies (one
clockwise, the other counter-clockwise) on the OC-12 ring, the OC-12 ring
capacity is limited to the OC-12 line rate.
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