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Cisco Bug: CSCvv34847 - traffic black-holing after remove add of member, l2port and extlif entries are not programmed on LC

Last Modified

Sep 03, 2020

Products (1)

  • Cisco Network Convergence System 5500 Series

Known Affected Releases

7.2.1.BASE

Description (partial)

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.
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