No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.

Knowledge Base

Services of a Static LAG Were Unavailable When the Port Attribute Was Tag Aware

Publication Date:  2019-07-08  |   Views:  239  |   Downloads:  0  |   Author:  SU1001785403  |   Document ID:  EKB0000486021


Issue Description

A LAG was comprised of two ports on two switches at an office. One LAG port was connected directly with an optical fiber and the other LAG port was connected by means of the N4EFS0 board on an OptiX OSN 3500 NE. When manual LAG (LACP was not enabled) was enabled on the two switches, services were available. When static LAG (LACP was enabled) was enabled on the two switches, services were unavailable. The NE software was of version

Alarm Information


Handling Process

1. Verified that services were normal when manual LAG was enabled. Therefore, inferred that the transmission path was proper.
2. Compared with manual LAG, static LAG used LACP. Therefore, suspected that LACP packets were not transparently transmitted between the two switches and as a result, services were unavailable.
3. Used a local mirror tool but failed to get any LACP protocol packets. Checked relevant documents and learned that LACP protocol packets did not carry any VLAN tags. Therefore, suspected that the LACP protocol packets were discarded by the N4EFS0 board whose port attribute was "Tag Aware".
4. Visited the site and verified that the port attribute of the N4EFS0 board was "Tag Aware". Changed the port attribute to "Hybrid" and then found that services became available.

Root Cause

The port attribute of the N4EFS0 board was "Tag Aware" and therefore the N4EFS0 board discarded LACP protocol packets, which carried no VLAN tag.


To allow LACP protocol packets to be transparently transmitted when LAG is enabled, set the port attribute of the Ethernet board to "Access" or "Hybrid".