Cisco Systems 15454M6DC A-4, segment (see FigureA-3)., cannot be 1+1 or BLSR protected (see Figure A-4). The same rule applies at the UPSR bridge.

A-4
Cisco ONS 15454 Installation and Operations Guide
November 2001
AppendixA Circuit Routing
Manual Circuit Routing
•If you enabled Fully Path Protected, choose a diverse protect (a lternate) path for every unprotected
segment (see FigureA-3).
FigureA-3 Alternate paths for virtual UPSR segments
•For Multicard EtherSwitch circuits, the Fully Path Protected option is ignored.
•For a node that has a UPSR selector based on the links chosen, the input links to the UPSR selectors
cannot be 1+1 or BLSR protected (see Figure A-4). The same rule applies at the UPSR bridge.
FigureA-4 Mixing 1+1 or BLSR protected links with a UPSR
•Choose the links of Multicard EtherSwitch circuits in a shared packet ring to route from source to
destination back to source (see FigureA-5). Otherwise, a route (set of links) chosen with loops is
invalid.
55403
BLSR ring
1+1 1+1
1+1
Twoway Twoway
Twoway Twoway
Node 8Node 7
Node 5 Node 6
UPSR UPSR
TwowayTwoway
Node 4Node 3
Node 1 Node 2
Twoway
Node 12Node 11
Node 9 Node 10
Source
Path Segment 1
UPSR/MESH
protected
Needs alternate path
from N1 to N2
Drop
Path Segment 3
BLSR protected
Path Segment 2
1+1 protected Path Segment 4 1+1 protected
No need for alternate path
55404
Unprotected
UnprotectedUnprotected
Unprotected
Unprotected
Unprotected
1+1 protected
BLSR ring
Node 4
(destination)
Node 3
UPSR UPSR
UPSR UPSR
UPSR UPSR
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