Datasheet

11-20
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 11 Circuits and Tunnels
11.13 Manual Circuit Routing
Figure 11-6 Secondary Sources and Destinations
Several rules apply to secondary sources and destinations:
• CTC does not allow a secondary destination for unidirectional circuits, because you can always
specify additional destinations after you create the circuit.
• Primary and secondary sources should be on the same node.
• Primary and secondary destinations should be on the same node.
Note DRI and open-ended SNCP nodes allow primary and secondary sources and destinations on
different nodes.
• Secondary sources and destinations are permitted only for regular high-order or low-order
connections (not for low-order tunnels and multicard EtherSwitch circuits).
• For point-to-point (straight) Ethernet circuits, only VC endpoints can be specified as multiple
sources or drops.
For bidirectional circuits, CTC creates an SNCP connection at the source node that allows traffic to be
selected from one of the two sources on the ONS 15454 SDH network. If you check the Fully Path
Protected option during circuit creation, traffic is protected within the ONS 15454 SDH network. At the
destination, another SNCP connection is created to bridge traffic from the ONS 15454 SDH network to
the two destinations. A similar but opposite path exists for the reverse traffic flowing from the
destinations to the sources. For unidirectional circuits, an SNCP drop-and-continue connection is created
at the source node.
11.13 Manual Circuit Routing
Routing circuits manually allows you to:
• Choose a specific path, not necessarily the shortest path.
• Choose a specific VC4/VC3/TUG3/TUG2/VC12/VC11 on each link along the route.
• Create a shared packet ring for multicard EtherSwitch circuits.
• Choose a protected path for multicard EtherSwitch circuits, allowing virtual SNCP segments.
83948
Primary source
Secondary source
Primary destination
Secondary destination
Vendor A
network
Vendor B
network
ONS network