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Cisco ONS 15600 Reference Manual, R7.2
Chapter 7 Circuits and Tunnels
7.3 Cross-Connect Card Bandwidth
7.3 Cross-Connect Card Bandwidth
The single shelf cross-connect card (SSXC) cross-connect cards perform port-to-port, time-division
multiplexing (TDM). The STS matrix has the capacity for 6144 STS terminations. Because each STS
circuit requires a minimum of two terminations, one for ingress and one for egress, the SSXC has a
capacity for 3072 STS circuits. However, this capacity is reduced at path protection and 1+1 nodes
because three STS terminations are required at circuit source and destination nodes and four
terminations are required at 1+1 circuit pass-through nodes. path protection pass-through nodes only
require two STS terminations.
7.4 DCC Tunnels
SONET provides four data communications channels (DCCs) for network element operations,
administration, maintenance, and provisioning: one on the SONET Section layer (DCC1) and three on
the SONET Line layer (DCC2, DCC3, DCC4). The ONS 15600 uses the Section DCC (SDCC) for
ONS 15600 management and provisioning. An SDCC and Line DCC (LDCC) each provide 192 Kbps of
bandwidth per channel. The aggregate bandwidth of the three LDCCs is 576 Kbps. You can tunnel
third-party SONET equipment across ONS 15600 networks using one of two tunneling methods, a
traditional DCC tunnel or an IP-encapsulated tunnel.
7.4.1 Traditional DCC Tunnels
In traditional DCC tunnels, you can use the three Line DCCs (LDCCs) and the SDCC (when not used
for ONS 15600 DCC terminations). A DCC tunnel endpoint is defined by slot, port, and DCC, where
DCC can be either the SDCC or one of the LDCCs. You can link LDCCs to LDCCs and link SDCCs to
SDCCs. You can also link an SDCC to an LDCC and an LDCC to an SDCC. To create a DCC tunnel,
connect the tunnel endpoints from one ONS 15600 optical port to another. Table 7-5 lists the DCC
tunnels that you can create.
When you create DCC tunnels, keep the following guidelines in mind:
•
Each ONS 15600 can have up to 64 DCC tunnel connections.
•
An SDCC that is terminated cannot be used as a DCC tunnel endpoint.
•
An SDCC that is used as an DCC tunnel endpoint cannot be terminated.
•
All DCC tunnel connections are bidirectional.
Table 7-5 DCC Tunnels
DCC SONET Layer SONET Bytes
DCC1 Section D1 to D3
DCC2 Line D4 to D6
DCC3 Line D7 to D9
DCC4 Line D10 to D12