363-206-295
Administration and Provisioning
8-32 Issue 1 December 1997
The OC-3 (VT level) cross-connections are:
■ At CO-1: a-1-4:m-3-2-1
The first VT in the second VTG is assigned between CO and CO-1. This
slot will be used to transport the DS1 that will terminate on port a-1-4.
■ At RT1-1: b-2-1:m-1-2-1
The above DS1 will leave the system from port b-2-1 at RT1-1. The VTG/
VT slot (-2-1) is set by the cross-connection at CO-1. Because OC-12 STS
mb-1 is dropped to the first STS in this OC-3 extension (m-1), port b-2-1 is
cross-connected to m-1-2-1.
■ At RT2-2: m-2-2-1:m-2-2-1
At RT2, time slot mb-1 is dropped to the second STS going to RT2-2
(m-2). The VT/VTG assignment remains -2-1. A VT pass-through cross-
connection is needed to enable future DS1s to be dropped at RT2-2. If
drops will never be needed, STS pass-through cross-connections can be
used.
■ At RT3-3: m-3-2-1:m-3-2-1
The VT above must also be passed through RT3-3. As before, the VTG/VT
is -2-1. The OC-12 time slot is dropped to the third STS in the OC-3 in this
segment.
With these cross-connections, DS1s originating at any of the four OC-3 nodes can
be terminated at any one of the others with VT cross-connections at those nodes
only. The STS "pipe" is in place with the OC-12 cross-connections. As was the
case with the example DS1, two VT drop cross-connections and two pass-through
cross-connections are needed.
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