Cisco 1921 WAP321

[nvaghani82]

Hi,

The WAP321 has VLAN 1 2 and 3. 1=Management 2=Office Wi-Fi 3=Guest Wi-Fi. WAP is connect to SG-200 50P on trunk port. VLAN 2 no problem, working fine and getting dhcp from server. VLAN 3 on the other hand gets nothing, only when manually assigning IP to device i can hit the Cisco landing page. I am using 1921 router with sub interfaces configured (dot1q encapsulation) connected to SG-200. Router config attached etc but really need a solution.

I believe this could be a Cisco Switch 802.1Q config problem but need some guidance, i think the switch port for trunk is config properly 1UP 2T 3T.

Any advice would be greatly appreciated.

[Michael Swenson]

Thanks for contacting Cisco.

1UP, 2T and 3T is correct on the Sg200 switch.  The WAP's SSID for the Guest Wi-Fi should be set to VLan 3.  The Uplink port to the 1921 sould, also, be 1UP, 2T and 3T. 

To isolate the issue, setup a port on the SG200 as 3UP and connect your PC to that port.  If the PC does not get a Vlan 3 IP address, then the issue is with the 1921's trunk port or Vlan 3 DHCP configuration issue.

Regards,

[nvaghani82]

Hi Michael,

Thank you for your support on this matter. The SG 200 won't allow 2 Tagged Vlans!! When devices are assigned static IPs connection is fine. VLAN2 works fine and dhcp is coming from same source so really hoped you suggestion was going to work. Originally I thought it was restrictions on switch as its only layer2 but I understand 802.1q supports sub interfaces? Do you think it could be routing issue on the 1921 config, may need some sort of config to help route traffic? 

[Michael Swenson]

Actually the SG200 will not allow two untagged vlans on a port.  You can have two tagged vlan on a trunk port.  The test I am suggesting is to make an unused port on the SG200 as 3 untagged, only.  This would isolate the SG200 and the router.  Basically, attempting to determine if the DHCP is working on Vlan 3.

Summary:

On the SG200, The uplink port to the router should be 1U, 2T and 3T

                         The uplink port to the WAP should be 1u, 2T and 3T

On the router, the interface to the Sg200 should be 1U ( native), 2T and 3T

If static IP connections work then you have a DHCP issue on Vlan 3.  Also, the routing is correct if the static IP works.

Best Regards,