Hello,
i would like to know if there is a limitation to the ,,switchport private-vlan association trunk" functionality.


The thing is, i would like to have on multiple interfaces (let's say 40) private-vlan trunk ports in this configuration:

switchport mode private-vlan trunk secondary
switchport private-vlan association trunk 10 100
switchport private-vlan trunk allowed vlan 10,100,1000    (the 10 is here i think not needed, need to test that -> only 100 and 1000 tagged packets arrive on the interface)

where 10 is the primary vlan, 100 is the secondary - isolated vlan and 1000 is an MGMT vlan. So on the interfaces there are tagged packets with the vlan tag 100 for user traffic and 1000 for the management interface of AP. The behaviour: L2 isolation of users through private vlan functionality.


Problem:
I can configure only on 20 interfaces the ,,switchport private-vlan association trunk" command. 

          Failure Information
---------------------------------------
Interfaces failed to be configured : 4
---------------------------------------
Interface             Error
---------------------------------------
          Failure Information
---------------------------------------
Interfaces failed to be configured : 4
---------------------------------------
Interface             Error
---------------------------------------
Gi1/0/21-Gi1/0/24  Errors in configuring private VLAN.Please refer to system log for more information

<188> Sep 5 23:58:25 A_N2024P_95.20-1 DOT1Q[emWeb]: dot1q_pvlan.c(4656) 838 %% WARN Max private VLAN domains are already configured on Gi1/0/24
<188> Sep 5 23:58:25 A_N2024P_95.20-1 DOT1Q[emWeb]: dot1q_pvlan.c(4656) 838 %% WARN Max private VLAN domains are already configured on Gi1/0/23
<188> Sep 5 23:58:25 A_N2024P_95.20-1 DOT1Q[emWeb]: dot1q_pvlan.c(4656) 833 %% WARN Max private VLAN domains are already configured on Gi1/0/22
<188> Sep 5 23:58:25 A_N2024P_95.20-1 DOT1Q[emWeb]: dot1q_pvlan.c(4656) 832 %% WARN Max private VLAN domains are already configured on Gi1/0/21

It seems there is a limit of maximum 20 ports, that can be associated with an private-vlan. Tried also to configure the interfaces on the second and third unit in the stack.

I have such switches in multiple configurations (stack of 3 | stack of N2024P | N2048 | N2048P. Tried this FW: 6.6.0.24, 6.6.3.12 and 6.6.3.14.

Workaround:

A stupid workaround would be to split out the switches from the stack -> make them standalone and configure on each one 20 private-vlan associated trunk ports.




Any suggestions? Is this a BUG?

Rest of the configuration:

vlan 10,100,1000
exit
vlan 10
private-vlan primary
private-vlan association 100
vlan 100
private-vlan isolated
vlan 1000
name MGMT

slot 1/0 3    ! Dell EMC Networking N2024P
slot 2/0 2    ! Dell EMC Networking N2048
slot 3/0 2    ! Dell EMC Networking N2048


interface Gi1/0/1
storm-control broadcast action trap
storm-control multicast action trap
storm-control unicast action trap
spanning-tree portfast
switchport mode private-vlan trunk secondary
switchport private-vlan association trunk 10 100
switchport private-vlan trunk allowed vlan 10,100,1000
ipv6 traffic-filter ipv6filter in 1
ip access-group MBLOCK in 2
ip access-group MBLOCK out 1
exit