Datasheet

11-21
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 11 Circuits and Tunnels
11.13 Manual Circuit Routing
CTC imposes the following rules on manual routes:
• All circuits, except multicard EtherSwitch circuits in a shared packet ring, should have links with a
direction that flows from source to destination. This is true for multicard EtherSwitch circuits that
are not in a shared packet ring.
• If you enabled Fully Path Protected, choose a diverse protect (alternate) path for every unprotected
segment (Figure 11-7).
Figure 11-7 Alternate Paths for Virtual SNCP Segments
•
For multicard EtherSwitch circuits, the Fully Path Protected option is ignored.
• For a node that has an SNCP selector based on the links chosen, the input links to the SNCP selectors
cannot be 1+1 or MS-SPRing protected (Figure 11-8). The same rule applies at the SNCP bridge.
Figure 11-8 Mixing 1+1 or MS-SPRing Protected Links with an SNCP
83949
MS-SPRing
1+1 1+1
1+1
Two way Two way
Two way Two way
Node 8Node 7
Node 5 Node 6
SNCP SNCP
Two wayTwo way
Node 4Node 3
Node 1 Node 2
Two way
Node 12Node 11
Node 9 Node 10
Source
Path Segment 1
SNCP/mesh
protected
Needs alternate path
from N1 to N2
Drop
Path Segment 3
MS-SPRing protected
Path Segment 2
1+1 protected
Path Segment 4
1+1 protected
No need for alternate path
83950
Unprotected
UnprotectedUnprotected
Unprotected
Unprotected
Unprotected
1+1 protected
MS-SPRing
Node 4
(destination)
Node 3
SNCP SNCP
SNCP SNCP
SNCP SNCP
Node 4Node 3
Node 1
(source)
Node 2
(destination)
Node 1
(source)
Node 2
Node 1
(source)
Node 2
Node 4
(destination)
Node 3
Illegal
Illegal
Unprotected
Legal