Working and Protect Paths

Question

Running a 17 node ONS-15454, UPSR Ring with Software ver. 6.0.3.
Why is it that when viewing or editing some circuits you do not see a Protect Path? On most circuits, you see a green working path and the purple protect path. We occasionally see circuits that have no protect path, only a green path that travels the entire ring. We can manually force to protect, which then clearly defines the protect path, but when we "Clear" the Switch State it reverts back to showing no protect path.
Why would these few circuits not have a defined protect path that shows up in the circuit details? Was there a problem when the circuit was originally created?

Answer 1

Curt,
When a UPSR circuit is created, CTC evaluates the available receive paths at each end of the circuit and will select the best available path as its primary path.
In the Circuit edit screen any path that has a working direction on it will be shown in green while a protect is shown in purple.
When you are seeing Green on both sides of the ring, this is an indication that the receivers for each side are using opposite paths.
If you have reversion enabled, the default path of the circuit will be restored after the hold down timer for the UPSR switch has cleared.
If you are concerned about keeping all traffic on one side of a ring, when you create the circuit you can select the "Provision working go & return on Primary path" option under the UPSR box of the Circuit Creation wizard.
Please see the following link for further details:
http://www.cisco.com/en/US/docs/optical/15000r6_0/15454/sonet/procedure/guide/r60dlp2.html#wp1047917
DLP-A218 Provision Path Protection Selectors