Cisco Systems 15454M6DC Manual De Usuario

A-4

Cisco ONS 15454 Installation and Operations Guide

November 2001

Appendix A Circuit Routing

Manual Circuit Routing

•

If you enabled Fully Path Protected, choose a diverse protect (alternate) path for every unprotected
segment (see

Figure A-3

Figure A-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.

Figure A-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

Figure A-5

). Otherwise, a route (set of links) chosen with loops is

invalid.

55403

BLSR ring

1+1

Twoway

Node 8

Node 7

Node 5

Node 6

UPSR

Twoway

Node 4

Node 3

Node 1

Node 2

Twoway

Node 12

Node 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

1+1 protected

BLSR ring

Node 4

(destination)

Node 3

UPSR

Node 4

Node 3

Node 1
(source)

Node 2

(destination)

Node 1
(source)

Node 2

Node 1
(source)

Node 2

Node 4

(destination)

Node 3

Illegal

Unprotected

Legal