I brought my family to New York City a couple of months ago for a vacation and to celebrate my mom's birthday. We stayed in a hotel near Times Square, which made it easy to explore interesting places around Manhattan. We visited places like Rockefeller Center (Top of the Rock), Central Park, Liberty Island and had apple picking in Upstate New York.
WLAN Controller
At the heart of the centralized WLAN architecture model is the WLAN controller (see Figure 10.16). WLAN controllers are often referred to as wireless switches because they are indeed an Ethernet-managed switch that can process and forward data at the Data-Link layer (layer 2) of the OSI model. Many of the WLAN controllers are multilayer switches that can also route traffic at the Network layer (layer 3). However, wireless switch has become an outdated term and does not adequately describe the many capabilities of a WLAN controller.
AP Management - As mentioned earlier, the majority of the access point functions such as power, channels, and supported data rates are configured on the WLAN controller. This allows for centralized management and configuration of APs. Some vendors use proprietary protocols for communications between the WLAN controller and their controller-based APs. These proprietary protocols can transfer configuration settings, update firmware, and maintain keep-alive traffic. A WLAN management protocol has gained acceptance. Many WLAN vendors use the Control and Provisioning of Wireless Access Points (CAPWAP) protocol for managing and monitoring access points.
Split MAC
The majority of WLAN controller vendors implement what is known as a split MAC architecture. With this type of WLAn architecture, some of the MAC services are handled by the WLAN controller, and some are handled by the access point. For example, the integration service and distribution system service are handled by the controller. WMM QoS methods are usually handled by the controller. Depending on the vendor, encryption and decryption of 802.11 data frames might be handled by the controller or by the AP.
You have already learned that 802.11 frames are tunneled between the controller-based APs and the WLAN controller. 802.11 data frames are usually tunneled to the controller because the controller's integration service transfers the layer 3-7 MSDU payload of the 802.11 data frames into 802.3 frames that are sent off to network resources. Effectively, the WLAN controller is needed to provide a centralized gateway to network resources for the payload of 802.11 data frames. 802.11 management and control frames do not have an upper-layer payload and therefore are never translated into 802.3 frames. 802.11 management and control frames do not necessarily need to be tunneled to the WLAN controller because the controller does not have to provide a gateway to network resources for these types of 802.11 frames.
In a split MAC architecture, many of the 802.11 management and control frame exchanges occur only between the client station and the controller-based access point and are not tunneled back to the WLAN controller. For example, beacons, probe responses, and ACKs may be generated by the controller-based AP instead of the controller. It should be noted that most WLAN controller vendors implement split MAC architectures differently. The Internet Engineering Task Force (IETF) has proposed a set of standards for WLAN controller protocols called Control and Provisioning of Wireless Access Points (CAPWAP). CAPWAP does define split MAC standrds.
In my wireless lab, I factory reset my WLC2 to prepare for high availability (HA) with WLC1.
Enter User Name (or 'Recover-Config' this one-time only to reset configuration to factory defaults)
User:admin
Password:*************
User:admin
Password:*************
<REBOOT WLC>
WLCNG Boot Loader Version 1.0.20 (Built on Jan 9 2014 at 19:02:44 by cisco)
Board Revision 0.0 (SN: PSZ19191L2A, Type: AIR-CT2504-K9) (P)
Verifying boot loader integrity... OK.
OCTEON CN5230C-SCP pass 2.0, Core clock: 750 MHz, DDR clock: 330 MHz (660 Mhz data rate)
CPU Cores: 4
DRAM: 1024 MB
Flash: 32 MB
Clearing DRAM........ done
Network: octeth0', octeth1, octeth2, octeth3
' - Active interface
E - Environment MAC address override
CF Bus 0 (IDE): OK
IDE device 0:
- Model: 1GB CompactFlash Card Firm: CF B61FK Ser#: C381100294A12t8E6Igo
- Type: Hard Disk
- Capacity: 977.4 MB = 0.9 GB (2001888 x 512)
Press <ESC> now to access the Boot Menu...
============================================================
Boot Loader Menu
============================================================
1. Run primary image (8.1.102.0) - Active
2. Run backup image (8.1.102.0)
3. Change active boot image
4. Clear configuration
5. Format FLASH Drive
6. Manually update images
------------------------------------------------------------
Enter selection: 4
Launching...
Launching images...
<OUTPUT TRUNCATED>
(Cisco Controller)
Welcome to the Cisco Wizard Configuration Tool
Use the '-' character to backup
Would you like to terminate autoinstall? [yes]:
System Name [Cisco_70:3e:24] (31 characters max):
Another way to perform a factory reset on a WLC is to type recover-config when prompted for user login.
(Cisco Controller)
Enter User Name (or 'Recover-Config' this one-time only to reset configuration to factory defaults)
User: recover-config
Initiating system recovery process... please wait
Writing to flash ...done
Rebooting system
Updating license storage ... Done.
Restarting system.
<OUTPUT TRUNCATED>
(Cisco Controller)
Welcome to the Cisco Wizard Configuration Tool
Use the '-' character to backup
Would you like to terminate autoinstall? [yes]:
At the heart of the centralized WLAN architecture model is the WLAN controller (see Figure 10.16). WLAN controllers are often referred to as wireless switches because they are indeed an Ethernet-managed switch that can process and forward data at the Data-Link layer (layer 2) of the OSI model. Many of the WLAN controllers are multilayer switches that can also route traffic at the Network layer (layer 3). However, wireless switch has become an outdated term and does not adequately describe the many capabilities of a WLAN controller.
AP Management - As mentioned earlier, the majority of the access point functions such as power, channels, and supported data rates are configured on the WLAN controller. This allows for centralized management and configuration of APs. Some vendors use proprietary protocols for communications between the WLAN controller and their controller-based APs. These proprietary protocols can transfer configuration settings, update firmware, and maintain keep-alive traffic. A WLAN management protocol has gained acceptance. Many WLAN vendors use the Control and Provisioning of Wireless Access Points (CAPWAP) protocol for managing and monitoring access points.
Split MAC
The majority of WLAN controller vendors implement what is known as a split MAC architecture. With this type of WLAn architecture, some of the MAC services are handled by the WLAN controller, and some are handled by the access point. For example, the integration service and distribution system service are handled by the controller. WMM QoS methods are usually handled by the controller. Depending on the vendor, encryption and decryption of 802.11 data frames might be handled by the controller or by the AP.
You have already learned that 802.11 frames are tunneled between the controller-based APs and the WLAN controller. 802.11 data frames are usually tunneled to the controller because the controller's integration service transfers the layer 3-7 MSDU payload of the 802.11 data frames into 802.3 frames that are sent off to network resources. Effectively, the WLAN controller is needed to provide a centralized gateway to network resources for the payload of 802.11 data frames. 802.11 management and control frames do not have an upper-layer payload and therefore are never translated into 802.3 frames. 802.11 management and control frames do not necessarily need to be tunneled to the WLAN controller because the controller does not have to provide a gateway to network resources for these types of 802.11 frames.
In a split MAC architecture, many of the 802.11 management and control frame exchanges occur only between the client station and the controller-based access point and are not tunneled back to the WLAN controller. For example, beacons, probe responses, and ACKs may be generated by the controller-based AP instead of the controller. It should be noted that most WLAN controller vendors implement split MAC architectures differently. The Internet Engineering Task Force (IETF) has proposed a set of standards for WLAN controller protocols called Control and Provisioning of Wireless Access Points (CAPWAP). CAPWAP does define split MAC standrds.
In my wireless lab, I factory reset my WLC2 to prepare for high availability (HA) with WLC1.
Enter User Name (or 'Recover-Config' this one-time only to reset configuration to factory defaults)
User:admin
Password:*************
User:admin
Password:*************
<REBOOT WLC>
WLCNG Boot Loader Version 1.0.20 (Built on Jan 9 2014 at 19:02:44 by cisco)
Board Revision 0.0 (SN: PSZ19191L2A, Type: AIR-CT2504-K9) (P)
Verifying boot loader integrity... OK.
OCTEON CN5230C-SCP pass 2.0, Core clock: 750 MHz, DDR clock: 330 MHz (660 Mhz data rate)
CPU Cores: 4
DRAM: 1024 MB
Flash: 32 MB
Clearing DRAM........ done
Network: octeth0', octeth1, octeth2, octeth3
' - Active interface
E - Environment MAC address override
CF Bus 0 (IDE): OK
IDE device 0:
- Model: 1GB CompactFlash Card Firm: CF B61FK Ser#: C381100294A12t8E6Igo
- Type: Hard Disk
- Capacity: 977.4 MB = 0.9 GB (2001888 x 512)
Press <ESC> now to access the Boot Menu...
============================================================
Boot Loader Menu
============================================================
1. Run primary image (8.1.102.0) - Active
2. Run backup image (8.1.102.0)
3. Change active boot image
4. Clear configuration
5. Format FLASH Drive
6. Manually update images
------------------------------------------------------------
Enter selection: 4
Launching...
Launching images...
<OUTPUT TRUNCATED>
(Cisco Controller)
Welcome to the Cisco Wizard Configuration Tool
Use the '-' character to backup
Would you like to terminate autoinstall? [yes]:
System Name [Cisco_70:3e:24] (31 characters max):
Another way to perform a factory reset on a WLC is to type recover-config when prompted for user login.
(Cisco Controller)
Enter User Name (or 'Recover-Config' this one-time only to reset configuration to factory defaults)
User: recover-config
Initiating system recovery process... please wait
Writing to flash ...done
Rebooting system
Updating license storage ... Done.
Restarting system.
<OUTPUT TRUNCATED>
(Cisco Controller)
Welcome to the Cisco Wizard Configuration Tool
Use the '-' character to backup
Would you like to terminate autoinstall? [yes]:
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