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capwap layer 3 question

Hello all,

I have a question about the capwap. Here http://www.cisco.com/en/US/docs/wireless/controller/7.0/configuration/guide/c70ovrv.html#wp1069102

I read, that 'CAPWAP communications between the controller and lightweight access points are conducted at Layer 3. Layer 2 mode does not support CAPWAP' and also 'The requirement for Layer 3 CAPWAP communications across subnets is that the controller and lightweight access points are connected through Layer 3 devices'. I cannot understand what's meaning the Layer 3 for CAPWAP? Maybe that the controller and capwap AP must be on the different subnets and connected across the subnets? But, now my controller and APs are on the same subnet and all are working. Example, if I connect a controller and capwap APs to Catalyst 2960s, and all are in same VLAN, I think that it also will work? I see the guide deploy 2500 controller and some scenarios there, where controller and APs are connected to Catalyst 3560 and Catalyst 3560 have only switchport trunk or switcport access settings. I can do this on the Catalyst 2960S too. Where is difference?

Thanks a lot.   

Everyone's tags (4)
2 ACCEPTED SOLUTIONS

Accepted Solutions

capwap layer 3 question

Hey VT,

Welcome to CSC...

Good question ...

Back on code 5.0 and prior codes you could set the controller as layer 2 or layer 3. Since 5.2 (CAPWAP), its only layer 3 and doesn't allow you the option to due layer 2.

Simply, if you deployed a WLC in layer 2 mode, your ap mangers are REQUIRED to be on the same subnet as your management interface. You couldn't add additional ap mangers on different subnets to break up your aps.

If you deployed in layer 3 mode, you could break out your AP mangers on the same subnet or different subnets.

Hope this helps

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
Cisco Employee

capwap layer 3 question

Layer 3 CAPWAP has nothing to do with AP being able on the same subnet of the WLC or not. AP and WLC can be on the same subent and operate at Layer 3.

When we say L2 LWAPP it means that it operates with native L2 ethernet frames.

The LWAPP Control and Data messages are encapsulated in Ethernet

frames using Ethertype "0xBBBB". In Layer 2 LWAPP mode, although the access points may get an IP

address via DHCP, all LWAPP communications between the access point and WLC are in Ethernet

encapsulated frames, not IP packets. The access points must be on the same Ethernet network as the

WLC. For this reason, Layer 2 LWAPP mode may not be suitable for scalability purposes in most

deployments. Furthermore, Layer 2 mode is supported only by the Cisco 410x and 440x series of WLCs

and the Cisco 1000 series access points. Layer 2 LWAPP is not supported by lightweight Cisco Aironet

1200, 1130AG, or 1240AG access points, or the Cisco 2006, WiSM, or WLCM series WLCs and ofcourse the new stuff.

In L3 mode LWAPP/CAPWAP are encapsulated in UDP packets instead of ethernet frames.

------------------------------------------------------------------------------------

Please make sure to rate correct answers

6 REPLIES

capwap layer 3 question

Hey VT,

Welcome to CSC...

Good question ...

Back on code 5.0 and prior codes you could set the controller as layer 2 or layer 3. Since 5.2 (CAPWAP), its only layer 3 and doesn't allow you the option to due layer 2.

Simply, if you deployed a WLC in layer 2 mode, your ap mangers are REQUIRED to be on the same subnet as your management interface. You couldn't add additional ap mangers on different subnets to break up your aps.

If you deployed in layer 3 mode, you could break out your AP mangers on the same subnet or different subnets.

Hope this helps

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
New Member

capwap layer 3 question

Hi George,

Thank you for your answer, now I understood.

capwap layer 3 question

You're welcome...

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
Cisco Employee

capwap layer 3 question

Layer 3 CAPWAP has nothing to do with AP being able on the same subnet of the WLC or not. AP and WLC can be on the same subent and operate at Layer 3.

When we say L2 LWAPP it means that it operates with native L2 ethernet frames.

The LWAPP Control and Data messages are encapsulated in Ethernet

frames using Ethertype "0xBBBB". In Layer 2 LWAPP mode, although the access points may get an IP

address via DHCP, all LWAPP communications between the access point and WLC are in Ethernet

encapsulated frames, not IP packets. The access points must be on the same Ethernet network as the

WLC. For this reason, Layer 2 LWAPP mode may not be suitable for scalability purposes in most

deployments. Furthermore, Layer 2 mode is supported only by the Cisco 410x and 440x series of WLCs

and the Cisco 1000 series access points. Layer 2 LWAPP is not supported by lightweight Cisco Aironet

1200, 1130AG, or 1240AG access points, or the Cisco 2006, WiSM, or WLCM series WLCs and ofcourse the new stuff.

In L3 mode LWAPP/CAPWAP are encapsulated in UDP packets instead of ethernet frames.

------------------------------------------------------------------------------------

Please make sure to rate correct answers

capwap layer 3 question

+5

A very tecnical anwser to my simple anwser ..

Good stuff!

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
Cisco Employee

capwap layer 3 question

Thanks George

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