Quick vlan/trunk question

Unanswered Question
Jun 27th, 2012
User Badges:

I set up my wlc virtual interfaces, my dhcp scopes etc... now i just want to make sure i dont interrupt things on our core switch by addidn a trunck in the wrong place etc.  here is a pic of our vlans on a procurve switch.  can i just add the port H20 as a trunk or do i have to make A1 a trunk also since that connects directly to our router?  will i have to change anything on the other vlan?

i only ask this because im working remotely because of surgery and if something needs to be physically reset, theres no one to do it.

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Stephen Rodriguez Wed, 06/27/2012 - 13:04
User Badges:
  • Purple, 4500 points or more

If i'm remembering my HP terms correctly, trunk is what they call an etherchannel.  So a trunk would be multiple ports going to the same device.

you should only need to set the port to be tagged on the VLAN for the dynamic interface, (management as well if you tagged it on the WLC.)


Please remember to rate useful posts, and mark questions as answered

tdean1965 Wed, 06/27/2012 - 13:15
User Badges:

Not a fan of GUI's on switches but in this case, you can select the port and theres a menu to change to trunk, lacp or something else.. so only the port from the WLC to the core switch would need to be a trunk? id probably want to change the mode to 100 full duplex too... there were tons of errors on this port.

tdean1965 Wed, 06/27/2012 - 13:33
User Badges:

its a 2106, is this the code?

i guess im tagging the guest wlan i created.

the mgt interface is

default router (GW) is

the guest vlan is going to be and use itself for dhcp.

i added a subinterface to our router for the new vlan 5.  on our core switch (connected directly to the router) i was wondering if i need to only trunk the port the WLC is connected to (H20) of if i have to do that AND the port that connects to the router.(A1). and if i have to trunk A1, will that cause a problem with the native vlan the rest of the company runs on?

Saravanan Lakshmanan Wed, 06/27/2012 - 13:15
User Badges:
  • Cisco Employee,

could you attach the topology with physical connection.

#onboard dhcp server on wlc is only for wireless clients to get dhcp ip. dhcp proxy should be enabled for same to work.

#proxy can be enabled/disabled when using ext dhcp server, if you prefer to mask the dhcp server ip then have the dhcp proxy enabled.

#dhcp would happen using the vlan ip interface mapped for that wlan.

#WLC doesn't support spanning tree.

#WLC is Layer2 and you need external L3 device for routing.

#All interfaces that are tagged on WLC mapped physical port should connect to uplink trunk of the switch. and you need to connect the uplink to your core switch/router on trunk.

#allow only the vlans that needs to be allowed on trunk

tdean1965 Fri, 06/29/2012 - 15:33
User Badges:

oh sorry, physical is very basic.  2 sites connected via EVPL (router on a stick at each location) Site 1 has the core switch, the WLC is connected to port H20 and the switch is connected to the router via port A1.  my question is, does A1 have to be a trunk also? Along with H20? Also, the untagged traffic will pass without issue, correct?

heres the GUI of the vlans.

Saravanan Lakshmanan Mon, 07/02/2012 - 15:02
User Badges:
  • Cisco Employee,

Like mentioned above WLC is an Layer-2 device, so your uplink switch needs to be configured as Trunk to allow all vlan traffic from & to between WLC and the switch. If you need routing through external router from that switch & WLC then yes you need to configure trunk and sub interfaces on the router.


This Discussion