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Cisco ONS 15454 Reference Manual, R7.0
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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 — —
