Datasheet

11-22
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 11 Circuits and Tunnels
11.13 Manual Circuit Routing
• Choose the links of multicard EtherSwitch circuits in a shared packet ring to route the circuit from
source to destination back to source (Figure 11-9). Otherwise, a route (set of links) chosen with
loops is invalid.
Figure 11-9 Ethernet Shared Packet Ring Routing
• Multicard EtherSwitch circuits can have virtual SNCP segments if the source or destination is not
in the SNCP domain. This restriction also applies after circuit creation; therefore, if you create a
circuit with SNCP segments, Ethernet drops cannot exist anywhere on the SNCP segment
(Figure 11-10).
Figure 11-10 Ethernet and SNCP
• Low-order tunnels cannot be the endpoint of an SNCP segment. A SNCP segment endpoint is where
the SNCP 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 11-9 through Table 11-12 on page 11-23 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
83951
SNCP Segment
Legal
Node 8Node 7
Node 5Node 2
Node 11 Node 11
Node 6
Source
Drop
SNCP Segment
Illegal
Node 8Node 7
Node 5 Node 6
Source
Drop
Table 11-9 Bidirectional VC/TUG/Regular Multicard EtherSwitch/Point-to-Point (Straight)
Ethernet Circuits
Connection Type
Number of
Inbound Links
Number of
Outbound Links Number of Sources Number of Drops
SNCP—21—
SNCP2——1
SNCP 2 1 — —
SNCP 1 2 — —
SNCP1——2