10-21
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter10 Circuits and Tunnels
10.12 Manual Circuit Routing
Although virtual SNCP segments are possible in low-order tunnels, low-order tunnels are still
considered unprotected. If you need to protect low-order circuits, use two indepe ndent low-order tunnels
that are diversely routed or use a low-order tunnel that is routed over 1+1, MS-SPRing, or a mixture of
1+1 and MS-SPRing links.
Table10-9 Unidirectional Circuit
Connection Type
Number of
Inbound Links
Number of
Outbound Links
Number of
Sources
Number of
Drops
One way 1 1 — —
SNCP head end 1 2 — —
SNCP head end — 2 1 —
SNCP drop and
continue
2— —1+
Table10-10 Multicard Group Ethernet Shared Packet Ring Circuit
Connection Type
Number of
Inbound Links
Number of
Outbound Links
Number of
Sources
Number of
Drops
Intermediate Nodes Only
SNCP21——
SNCP12——
Double SNCP 2 2 — —
Two way11—-—
Source or Destination Nodes Only
Ethernet11——
Table10-11 Bidirectional Low-Order Tunnels
Number of
Inbound Links
Number of
Outbound Links
Number of
Sources
Number of
Drops Connection Type
Intermediate Nodes Only
21——SNCP
12——SNCP
22——Double SNCP
1 1 — — Two way
Source Nodes Only
—1— — Low-order tunnel
endpoint
Destination Nodes Only
1 — — — Low-order tunnel
endpoint