VLAN Switch Uplink

jeremywatco Posts: 3
edited April 14 in Switch
Hi there,
Having issues with some Zyxel switches. Its a pretty simple setup. Two Zyxel switches with IP phones plugged into them. These IP phones have PC's plugged into the phones. 

I have the Zyxel's voice VLAN setup correctly so that the phones are getting automatically assigned the correct VLAN and the PC's are getting the correct VLAN.

I have VLAN 1 Data. VLAN10 Phones.

The phone server that hands out DHCP is set to PVID 10 and Tagged.

The other ports that the phones plugged into are set to PVID 1, ANY, and trunking (only way I could get each port to see both voice and data VLANs was to trunk them).

All is working fine on same switch as DHCP server.

NOW... same exact config on second switch. Again, its assigning the VLAN's automatically and correctly. But the issue is that the phone will not get DHCP from the server on the first switch. If I move that server onto one of the switch ports of the 2nd switch all works fine.

So this makes me pretty much certain that the issue is the uplinks between the switches not passing traffic correctly. These ports are set to PVID 1 and trunking just like all the other ports.

Any ideas? 


All Replies

  • Ace
    Ace Posts: 24  Freshman Member

    Hi jeremywatco

    Looks like you have created VLAN database of VLAN 10 on the switch and enable vlan trunking on the uplink/downlink ports of switches.

    Because VLAN trunking is using for traffic forwarding of unknown vlans.
    If you create VLAN database then vlan trunking port still refer to VLAN database setting.

    You may need to configure uplink/downlink as fixed and tagged out for VLAN 10 and it should work.


  • Can 1 uplink tag both 1 & 10? I'm assuming disable trunking on all ports since all VLANs are know. 

  • Ace
    Ace Posts: 24  Freshman Member

    Yes, you can. But I don't think you need tagged out for VLAN 1, just tagged out for VLAN 10 should work.

    PC connect to phone and IP phones are connected to switch Port 1 to Port 9. Port 10 is uplink.

    All ports PVID are 1 and phone using voice vlan to transfer to VLAN 10.

    Below is my static vlan setting:

    VLAN 1: All ports are vlan 1 member and untagged out.

    VLAN 10: All ports are vlan 10 member and only uplink/downlink port is tagging.

    Following this configuration, VLAN 10 traffics will tag to forward between two switches. 
    BTW, only DHCP server port need to configure PVID to 10.

    This configuration is working in my office. Just for you reference.

  • Thank you, I'll try this tomorrow. I assume do this setup on both switches.. where I am tagging just on the ports that are connected switch to switch?
  • Ace
    Ace Posts: 24  Freshman Member
  • I am working on this scenrio. How do you get the DHCP for voice vlan from edge router or server.



  • Zyxel小編 Lucious
    Zyxel小編 Lucious Posts: 279  Zyxel Employee

    Hi @kaleemqureshi

    Make sure you set correct PVID (as voice VLAN) for the port to DHCP server, and set the port untagged-out.