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New Member

traffic flow

Hi,

I have a basic question to ask regarding the flow of traffic.

Following is the setup,

   WLC----> Core Switch ----> Firewall/Filtering Server ----> Internet  :  (Network A)

   WLC------> Core Switch -----> External Network : (Network B)

There are two seperate networks A & B. WLC on Network A is the remote controller & WLC on network B is the anchor controller.

The question is regarding network A users.

Network A WLC has dhcp server pointed to the Firewall/Filtering Server (which has the scope configured). I know that WLC A connections will be tunneled to WLCB as it is the main controller. But how will the dhcp request from a user in network A travel?

Will it travel from WLC A to WLC B or becuase the dhcp server is within Network A, users dhcp request will simply to WLC A & get redirected to Firewall/Filtering server in Network A?

Please reply with inputs. Thanks in advance.

6 REPLIES
VIP Purple

Re: traffic flow

Did you configure "Auto-Anchor" feature for the WLAN ? What type of WLAN is this ? is this a WLAN configured for guest traffic ?

If it is typical Guest WLAN, then WLC at network A won't have any L3 attachement of your clients. When client associations hits that WLC it will tunnel back to Anchor WLC who will manage the IP assignment to client. So Anchor WLC will go back to whereever you configured as DHCP server to get an IP for the client. So all L3 information with anchor WLC only.

HTH

Rasika

**** Pls rate all useful responses ****

New Member

traffic flow

yes there is anchor mobility enabled between them.

The wlans configured are for normal use & no guest traffic exists.

So, dhcp request for users connecting to remote controller will still end up going to anchor(main) controller. is that correct to say?

VIP Purple

Re: traffic flow

Yes, that should be the case.

To confirm you could get "show client detail " output of your foreign controller & anchor controller. That will tells us how the client associated to the network.

Post that output if you are not sure.

HTH

Rasika

**** Pls rate all useful responses ****

Re: traffic flow

Asymmetric tunneling breaks when an upstream router has reverse path filtering (RPF) enabled. In this case, the client traffic is dropped at the router because the RPF check ensures that the path back to the source address matches the path from which the packet is coming. When symmetric mobility tunneling is enabled, all client traffic is sent to the anchor controller and can then successfully pass the RPF check

Symmetric mobility tunneling is also useful in the following situations:

•If a firewall installation in the client packet path drops packets because the source IP address does not match the subnet on which the packets are received.

•If the access-point group VLAN on the anchor controller is different than the WLAN interface VLAN on the foreign controller. In this case, client traffic could be sent on an incorrect VLAN during mobility events.

New Member

traffic flow

Thanks.

Problem here is , the clients at the remote end at times lose connectivity & during this time we see the mobility between remote controller & anchor controller has gone down.

No other logs are seen, it just says mobility is down & in matter of time, it resurfaces again.

There is a firewall in path between both controllers but that has been opened up for required communication.

Please advise with suggestions.

New Member

traffic flow

Kindly find the link whick may help your qury .

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a0080810880.shtml#t3

The impletmentation of wireles, dhcp server and Implementation best practise

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