Datasheet

11-12
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 11 Circuits and Tunnels
11.4 DCC Tunnels
or DS-3 cross-connects, or 1008 bidirectional E-1 cross-connects. The XC-VXC-10G card manages up
to 576 bidirectional STM-1 cross-connects, 576 bidirectional E-3 or DS-3 cross-connects, or 1344
bidirectional E-1 cross-connects.
The XC-VXL-10G, XC-VXL-2.5G, and XC-VXC-10G cards work with the TCC2/TCC2P card to
maintain connections and set up cross-connects within the node. You can create circuits using CTC.
Note Chapter 2, “Common Control Cards,” contains detailed specifications of the XC-VXL-10G,
XC-VXL-2.5G, and XC-VXC-10G cards.
11.4 DCC Tunnels
SDH provides four DCCs for network element operation, administration, maintenance, and
provisioning: one on the SDH regenerator section layer (RS-DCC) and three on the SDH multiplex
section layer, also called multiplex-section DCC (MS-DCC). A regenerator-section DCC (RS-DCC) and
multiplex-section DCC (MS-DCC) each provide 192 Kbps of bandwidth per channel. The aggregate
bandwidth of the three RS-DCCs is 576 Kbps. When multiple DCC channels exist between two
neighboring nodes, the ONS 15454 SDH balances traffic over the existing DCC channels. You can
tunnel third-party SDH equipment across ONS 15454 SDH networks using one of two tunneling
methods, a traditional DCC tunnel or an IP-encapsulated tunnel.
11.4.1 Traditional DCC Tunnels
In traditional DCC tunnels, the ONS 15454 SDH uses RS-DCC for inter-ONS-15454-SDH data
communications. It does not use the multiplex section DCCs; therefore, the MS-DCCs are available to
tunnel DCCs from third-party equipment across ONS 15454 SDH networks. If D4 through D12 are used
as data DCCs, they cannot be used for DCC tunneling.
A traditional DCC tunnel endpoint is defined by slot, port, and DCC, where DCC can be either the
RS-DCC, Tunnel 1, Tunnel 2, or Tunnel 3. You can link an RS-DCC to a MS-DCC (Tunnel 1, Tunnel 2,
or Tunnel 3) and a MS-DCC to an RS-DCC. You can also link MS-DCCs to MS-DCCs and link
RS-DCCs to RS-DCCs. To create a DCC tunnel, you connect the tunnel end points from one
ONS 15454 SDH STM-N port to another. Cisco recommends a maximum of 84 DCC tunnel connections
for an ONS 15454 SDH. Table 11-5 shows the DCC tunnels that you can create.
Figure 11-3 shows a DCC tunnel example. Third-party equipment is connected to STM-1 cards at
Node 1/Slot 3/Port 1 and Node 3/Slot 3/Port 1. Each ONS 15454 SDH node is connected by STM-16
trunk (span) cards. In the example, three tunnel connections are created, one at Node 1 (STM-1 to
STM-16), one at Node 2 (STM-16 to STM-16), and one at Node 3 (STM-16 to STM-1).
Table 11-5 DCC Tunnels
DCC SDH Layer SDH Bytes STM-1 (All Ports) STM-4, STM-16, STM-64
RS-DCC Regenerator Section D1 to D3 Yes Yes
Tunnel 1 Multiplex Section D4 to D6 No Yes
Tunnel 2 Multiplex Section D7 to D9 No Yes
Tunnel 3 Multiplex Section D10 to D12 No Yes