Symptom
In a VPWS case (AC and PW) with bundle as AC with members spanning across different line cards, removal of last bundle member from a particular LC leads the system to s/w database inconsistency.
Any further operation done - bundle member add/update leads to unknown failures.
Below is one such scenario where this condition leads to traffic loss:
Traffic drop will be seen on a bundle member, where the bundle has members across multiple LC's and last member is removed and added back.
Example: Bundle BE1201 with 2 members from LC5 and LC7. Now remove the member from LC7 and add it back to the bundle. Traffic flowing via LC7 will get dropped.
Conditions
Platform: ncs5500 - Modular chassis with multiple linecards.
LC : J+/J2
Image: 7.2.1
Bundle AC: Members from more than 1 LC
Trigger: Remove last member from one LC, add it back to different bundle or same bundle.
* Bundle has to be part of Attachment circuit and VPWS enabled.
* Issue will not be seen if local xconnect or local bridging.
Workaround
No Workaround to cleanup the system other than LC reload
Further Problem Description