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Cisco ONS 15454 Reference Manual, R7.0
78-17191-01
Chapter 11 Circuits and Tunnels
11.15 11.15 Manual Circuit Routing
Figure 11-12 Ethernet Shared Packet Ring Routing
Multicard EtherSwitch circuits can have virtual path protection segments if the source or destination
is not in the path protection domain. This restriction also applies after circuit creation; therefore, if
you create a circuit with path protection segments, Ethernet destinations cannot exist anywhere on
the path protection segment (Figure 11-13).
Figure 11-13 Ethernet and Path Protection
A VT tunnel cannot be the endpoint of a path protection segment. A path protection segment
endpoint is where the path protection selector resides.
If you provision full path protection, CTC verifies that the route selection is protected at all segments.
A route can have multiple protection domains with each domain protected by a different scheme.
Table 11-12 through Table 11-15 on page 11-31 summarize the available node connections. Any other
combination is invalid and generates an error.
55405
Ethernet source
Ethernet destination
Node 4Node 3
Node 1 Node 2
55406
Path Protection
Segment
Legal
Node 8Node 7
Node 5Node 2
Node 11 Node 11
Node 6
Source
Drop
Path Protection
Segment
Illegal
Node 8Node 7
Node 5 Node 6
Source
Drop
Table 11-12 Bidirectional STS/VT/Regular Multicard EtherSwitch/Point-to-Point (Straight)
Ethernet Circuits
Connection Type
Number of
Inbound Links
Number of
Outbound Links
Number of
Sources
Number of
Destinations
UPSR — 2 1
UPSR 2 — 1
UPSR 2 1 — —
UPSR 1 2 — —
UPSR 1 — 2
UPSR — 1 2
Double UPSR 2 2