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Cisco ONS 15600 SDH Reference Manual, Release 9.0
78-18400-01
Chapter 7 Circuits and Tunnels
7.3 Cross-Connect Card Bandwidth
7.3 Cross-Connect Card Bandwidth
The single shelf cross-connect card (SSXC) performs port-to-port time-division multiplexing (TDM).
The VC matrix has the capacity for 2048 VC4 and/or 6144 VC3 terminations. Because each VC4/VC3
circuit requires a minimum of two terminations, one for ingress and one for egress, the SSXC has a
capacity for 1024 VC4 and 3072 VC3 circuits respectively. However, this capacity is reduced at SNCP
and 1+1 nodes because three VC4/VC3 terminations are required at circuit source and destination nodes
and four terminations are required at 1+1 circuit pass-through nodes. SNCP pass-through nodes only
require two VC4/VC3 terminations.
7.4 DCC Tunnels
SDH provides four data communications channels (DCCs) for network element operations,
administration, maintenance, and provisioning (OAM&P): one on the SDH Section layer (DCC1) and
three on the SDH Line layer (DCC2, DCC3, DCC4). The ONS 15600 SDH uses the regenerator-section
DCC (RS-DCC) for ONS 15600 SDH management and provisioning. An RS-DCC and multiplex-section
(MS-DCC) each provide 192 Kbps of bandwidth per channel. The aggregate bandwidth of the three
MS-DCCs is 576 Kbps. You can tunnel third-party SDH equipment across ONS 15600 SDH 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 MS-DCCs and the RS-DCC (when not used for
ONS 15600 SDH DCC terminations). A DCC tunnel endpoint is defined by slot, port, and DCC, where
DCC can be either the RS-DCC or one of the MS-DCCs. You can link MS-DCCs to MS-DCCs and link
RS-DCCs to RS-DCCs. You can also link an RS-DCC to an MS-DCC and an MS-DCC to an RS-DCC.
To create a DCC tunnel, connect the tunnel endpoints from one ONS 15600 SDH optical port to another.
lists the DCC tunnels that you can create.
When you create DCC tunnels, keep the following guidelines in mind:
•
Each ONS 15600 SDH can have up to 64 DCC tunnel connections.
•
An RS-DCC that is terminated cannot be used as a DCC tunnel endpoint.
•
An RS-DCC that is used as an DCC tunnel endpoint cannot be terminated.
•
All DCC tunnel connections are bidirectional.
Table 7-5
DCC Tunnels
DCC
SDH Layer
SDH Bytes
DCC1
RS-DCC
D1 to D3
DCC2
MS-DCC
D4 to D6
DCC3
MS-DCC
D7 to D9
DCC4
MS-DCC
D10 to D12