MR46 SSID vlan tagging delay

Solved
AdilShah
Conversationalist

MR46 SSID vlan tagging delay

We've got the setup as below;

  1. VLAN Management => dhcp on a vm
  2. VLAN LAN 1 => dhcp on a vm
  3. VLAN LAN2 => dhcp on a vm
  4. VLAN Voice => dhcp on a vm

Switchpoort where AP is connected to: Trunk native vlan (management vlan) Allowed VLAN (all) => this is working

AP: Management vlan with dhcp ip getting from the dhcp server on a VM in de LAN1 => this is working

SSID: Employee (Tagged with vlan LAN2 and vlan VOICE) => configured SSID in Bridge Mode and it's working

 

AP is getting ip from the VLAN management, SSID is broadcasting and the users are able to connect to it.
After connection there is a delay. Users getting the message that your pc is not connected to internet and the internet symbol does not change. After a minute or two the wifi symbol changes and then it works fine but the question is

"Where does this delay come from and how can i get this proces speed up?"

 

1 Accepted Solution
AdilShah
Conversationalist

After performing a wireshark capture I figured out what the issue was en resolved the problem.
VLAN tagging in bridge mode where the AP is in a different VLAN can get tricky as the broadcast from client to dhcp server is in layer-2 and the dhcp server offers in layer-2 and layer-3 (broadcast and unicast). See below article;

Solved: DHCP DORA--> Broadcasts or Unicasts? - Cisco Community


De solution was to change the mode from Bridge to layer-3. The delay problem is resolved now.

View solution in original post

7 Replies 7
alemabrahao
Kind of a big deal
Kind of a big deal

First of all, what type of authentication are you using?

Is 802.11w enabled in the SSID configuration?

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.
AdilShah
Conversationalist

We are using pre-shared key without 802.11w enabled.

Brash
Kind of a big deal
Kind of a big deal

During the time that the computer is saying there's no Internet connection, it would be worth doing some tests:

- Does the VM have an IP?

- if so, what can you reach via ping? This can help identify where you're connection is stopping.

- if not, you're troubleshooting a DHCP issue and need to do some captures or look at the DHCP server logs to see where the DHCP requests are being lost.

AdilShah
Conversationalist

If i change the SSID to get ip from the same dhcp server but but different scope (Management VLAN where the AP is on), there is no delay. Clients do get ip's from the DHCP server but there is a delay which i can't figure out where. 

alemabrahao
Kind of a big deal
Kind of a big deal

Did you check if the behavior is the same on the wired network?

If it works well for the other scopes, I hardly think it's a problem with the Wifi.

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.
PhilipDAth
Kind of a big deal
Kind of a big deal

This is the methods Windows uses to detect an Internet connection:
https://devblogs.microsoft.com/oldnewthing/20221115-00/?p=107399

 

You can manually test these right after connection to see if they are working or not, and if not - why not.

 

 

Also, you say it is a VM.  Is the VM running on a physical host, and that physical host has the WiFi NIC, and the VM is bridged through to that Wifi NIC?  Is there more than one VM trying to use the same WiFi NIC?

 

Do non-VM machines have the same issue?

 

If you have client isolation enable - you could experiment with turning it off.

https://documentation.meraki.com/MR/Firewall_and_Traffic_Shaping/Wireless_Client_Isolation

 

AdilShah
Conversationalist

After performing a wireshark capture I figured out what the issue was en resolved the problem.
VLAN tagging in bridge mode where the AP is in a different VLAN can get tricky as the broadcast from client to dhcp server is in layer-2 and the dhcp server offers in layer-2 and layer-3 (broadcast and unicast). See below article;

Solved: DHCP DORA--> Broadcasts or Unicasts? - Cisco Community


De solution was to change the mode from Bridge to layer-3. The delay problem is resolved now.

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