10-19
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter10 Circuits and Tunnels
10.12 Manual Circuit Routing

Figure10-8 Mixing 1+1 or MS-SPRing Protected Links with an SNCP

Choose the links of multicard EtherSwitch circuits in a shared packet ring to route from source to

destination back to source (Figure10-9). Otherwise, a route (set of links) chosen with loops is invalid.

Figure10-9 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 10-10).
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
55405
Ethernet source
Ethernet destination
Node 4Node 3
Node 1 Node 2