This KB addresses a situation which can lead to traffic loss associated with the native vlan
If a LAG interface (such as ae0) has more than one logical units (IFLs) and native vlan is moved from one logical unit to another logical unit in the same configuration, packets with native vlan tag will not be forwarded to the intended port.
When this problem occurs, traffic with associated with native vlan tag on LAG interface will not be forwarded.
Configuration
The initial configuration of LAG interface where traffic is getting forwarded correctly. VLAN 301 is configured as native vlan and associated with unit 301
user@switch# show interfaces ae0
flexible-vlan-tagging;
native-vlan-id 301;
unit 0 {
family ethernet-switching {
interface-mode trunk;
vlan {
members 1001-1002;
}
unit 301 {
members [ 301 1000 ];
Later the configuration is modified to move native vlan from unit 301 to unit 0 in the same commit. This will cause native vlan traffic to be dropped
members [ 301 1001 1002 ]
members [ 1000 ];
Workaround
Split the configuration in two steps. First remove the native vlan from original logical unit and commit. Then add the native vlan to the new logical unit and commit.
Step1
root@jtac-QFX5120-48Y-8C-r110-BL# show | compare
[edit interfaces ae0 unit 301 family ethernet-switching vlan]
- members [ 301 1000 ];
+ members 1000;
{master:0}[edit]
root@jtac-QFX5120-48Y-8C-r110-BL# commit
Step2
[edit interfaces ae0 unit 0 family ethernet-switching vlan]
- members 1001-1002;
+ members [ 301 1001-1002 ];
This issue is due to a software bug has been fixed in multiple releases (23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R2, 25.3R1). Please upgrade to any of these are their subsequent versions.