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DHCP Relay - many SSID with different VLAN

namezys
New Contributor III

Hello. Maybe my understanding of the DHCP relay feature is wrong but let me try to explain what I want to get.

Current setup with general broadcast DHCP

Two SSID:

  • "ssid-10" with VLAN 10
  • "ssid-20" with VLAN 20

Everything is connected through a switch to MikroTik there I have a DHCP server

  • VLAN 10: 10.10.0.1, pool: 10.10.x.x
  • VLAN 20: 10.20.0.1, pool: 10.20.x.x

Everything works as expected:

  • if I connected to "ssid-10", I would get 10.10.x.x
  • if I connected to "ssid-20", I would get 10.20.x.x

DHCP Relay

I hope that I understand correctly how it should work (AP works as relay agent):

  1. wireless STA sends a broadcast DHCP request
  2. AP gets this broadcast request and sends a unicast request to the DHCP server that I preconfigured
    1. In other words, I have to configure different DHCP servers for each SSID: 10.10.0.1 and 10.20.0.1
  3. DHCP server responses to AP
  4. AP sends a response to the STA

Looks like that should work better than broadcast. However, without DHCP relay it works well so I'm just curios if it's possible to setup.

 

 

1 ACCEPTED SOLUTION

No, the DHCP relay is only configured in devices that works in L3. The AP works in L2.
We have the option "Directed MC/BC Threshold" that reduces multicast and broadcast traffic, but it doesn't apply to DHCP and ARP traffic:
https://docs.commscope.com/bundle/unleashed-200.9-onlinehelp/page/GUID-92FB1860-3276-4819-8A0F-78116...

 

Bruno Andrade | Principal TSE Bulldog Americas | RCNA | CWNA | CWDP
Follow me on LinkedIn

View solution in original post

5 REPLIES 5

bruno_andrade
RUCKUS Team Member

You don't need to set routes in the ZD. Your router (which is the gateway for your ZD) should have a route to the DHCP server. The ZD simply converts DHCP broadcast traffic into unicast and forwards it to the DHCP relay IPs using the default gateway configured in the ZD.

Bruno Andrade | Principal TSE Bulldog Americas | RCNA | CWNA | CWDP
Follow me on LinkedIn