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Cisco 5500 Series Wireless Controllers

Cisco Wireless LAN Controller Configuration Best Practices

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Table of Contents

Cisco Wireless LAN Controller (WLC) Configuration Best Practices

Introduction

Prerequisites

Requirements

Components Used

Best Practices

Network Design

Use PortFast on AP Connected Switch Ports

Interfaces Source (DHCP, SNMP, RADIUS, Multicast, and so on.)

Recommended SwitchPort Modes and VLAN Pruning

Network Connectivity

Use TAG Tagging for Management Interface

Use Multicast Forwarding Mode

Disable Internal DHCP

Security

Disable Local EAP

WPA2 + 802.1X WLAN

Identity Design Tip - Use AAA Override

Use Faster RADIUS Timeout

EAP Identity Request Timeout

EAPoL Key Timeout and Max Retries

EAP Request Timeout and Max Retries

CCKM Timestamp Validation

TACACS+ Management Timeout

Enable Infrastructure and Client Management Frame Protection (MFP)

Enable 802.11w Support

Change SNMPv3 Default User

Enable Network Time Protocol (NTP)

Enable 802.11r Fast Transition

DHCP Required Option

Rogue Management

Rogue Detection

Min-RSSI

Rogue Rules

Wi-Fi Direct

Channels Scanning for Rogues

Transient Rogue Interval

Enable Adhoc Rogue Detection

Enable Rogue Clients AAA Validation

Enable Rogue Clients MSE Validation

Wireless/RF

Disable Low Data Rates

Lower the Number of SSIDs

Enable Band Selection

Channel Widths

Application Visibility and Control (AVC)

Enable 802.11k for Optimal Roaming

Mobility

Configure Mobility Multicast Mode

Enable Fast SSID Changing

Enable CleanAir

Enable High Availability Client/AP SSO

AP Stateful switchover (AP SSO)

FlexConnect Best Practices

Cisco Wireless LAN Controller (WLC) Configuration Best Practices

Introduction

Mobility has rapidly changed the expectation of wireless network resources and the way users perceive it. Wireless has become the preferred option for users to access the network, and in a lot of cases the only practical one. This document offers short configuration tips that cover common best practices in a typical Wireless LAN Controller (WLC) infrastructure. The objective is to provide important notes that you can apply on most wireless network implementations.


Note Not all networks are alike. Therefore some of the tips might not be applicable on your installation. Always verify them before you perform any changes on a live network.


Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

  • Knowledge of how to configure the Wireless LAN Controller (WLC) and Lightweight Access point (LAP) for basic operation
  • Basic knowledge of Control And Provisioning of Wireless Access points (CAPWAP) protocol and wireless security methods

Components Used

The information in this document is based on these software and hardware versions:

  • Cisco Series WLC that runs software Release 7.6 and above.
  • Cisco 802.11n and 11ac series Access points

Note Any reference to WLCs is based on software Release 7.6 and above.


The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Best Practices

Network Design

These are the best practices for network design:

Use PortFast on AP Connected Switch Ports

For APs in local mode, configure the switch port with PortFast. To configure PortFast, set the port to be connected as a “host” port (switchport host command) or directly with the portfast command. This allows a faster join process for an AP. There is no risk of loops, as the CAPWAP APs never bridges between VLANs

Interfaces Source (DHCP, SNMP, RADIUS, Multicast, and so on.)

Per design, most of the CPU initiated traffic is sent from the management address in the controller. For example, SNMP traps, RADIUS authentication requests, multicast forwarding, and so on.

  • The default exception to this rule is DHCP related traffic. You can also enable on each SSID “radius interface overwrite”; and then the radius for this WLAN will be sent from the dynamic interface. However, this creates design issues with Bring Your Own Device (BYOD) flow and Change of Authorization (CoA).
  • Enabling radius interface overwrite on each SSID is important to take into account when you configure firewall policies, or design the network topology. It is important to avoid configuring a dynamic interface in the same sub-network as a server that has to be reachable by the controller CPU. For example, a RADIUS server, as it might cause asymmetric routing issues.
  • Radius can be sourced from a dynamic interface, with the Radius override feature. This should be used only when needed by the specific topologies.

Recommended SwitchPort Modes and VLAN Pruning

Always configure the switchports in “access mode” for the APs in local mode. For the switchports in trunk mode that go to the APs in FlexConnect mode (that do local switching) and to the WLCs, always prune the VLANs in order to allow only those VLANS configured on the FlexConnect AP and WLC. In addition, enter the switchport nonegotiate command on those trunks in order to disable Dynamic Trunking Protocol (DTP) on the switchport and avoid the need for the AP/WLC to process frames that are not needed as they do not support DTP. Also, resources would be wasted on the switch, which would attempt to negotiate with a device that cannot support it.

Network Connectivity

Following are the best practices for network connectivity:

Although most of the controller configuration is applied “on the fly”, it is good idea to reload controllers after you change these configuration settings:

Management address

SNMP configuration

HTTPS encryption settings

LAG mode (enable/disable), on this case it is mandatory

Use TAG Tagging for Management Interface

Cisco recommends to use VLAN tagging for the management interface on the WLC, as this is the only supported mode for HA scenarios. For untagged interface, the packet sent to and from the management interface assumes the Native VLAN of the trunk port to which the WLC is connected. However, if you want the management interface to be on a different VLAN, tag it to the appropriate VLAN with the command:

(Cisco Controller) >config interface vlan management <vlan-id>

Ensure that the corresponding VLAN is allowed on the switchport and tagged by the trunk (non-native vlan).

  • For all trunk ports that connect to the controllers, filter out the VLANs that are not in use.

For example, in Cisco IOS® switches, if the management interface is on VLAN 20, and VLAN 40 and VLAN 50 are used for two different WLANs, use this configuration command at the switch side:

Switch# switchport trunk allowed vlans 20,40,50

Do not leave an interface with a 0.0.0.0 address. For example, an unconfigured service port. It might affect DHCP handling in the controller.

This is how you verify:

(Cisco Controller) >show interface summary
Interface Name Port Vlan Id IP Address Type Ap Mgr
-------------------- ---- -------- --------------- ------- ------
ap-manager LAG 15 192.168.15.66 Static Yes
example LAG 30 0.0.0.0 Dynamic No
management LAG 15 192.168.15.65 Static No
service-port N/A N/A 10.48.76.65 Static No

Do not use link aggregation (LAG) unless all ports of the controller have the same Layer 2 configuration on the switch side. For example, avoid filtering some VLANs in one port, and not the others.

While using LAG, the traffic must arrive on the same dataplane. The controller relies on the switch for the load balancing decisions on traffic that come from the network. The controller expects that traffic that belongs to an AP always enter on the same data plane. 5500s are example of single data plane, in which traffic will always arrive on the same data plane.

WISM2 and 8500 are WLCs with two data planes. Whenever possible, the traffic needs to arrive on the same data plane. Commonly, there is sufficient bandwidth to move frames between data planes. However, if there is limited bandwidth, the traffic may be dropped.

This is how to verify the EtherChannel load balancing mechanism:

Switch#show etherchannel load-balance
EtherChannel Load-Balancing Configuration:
src-dst-ip

EtherChannel Load-Balancing Addresses Used Per-Protocol:
Non-IP: Source XOR Destination MAC address
IPv4: Source XOR Destination IP address
IPv6: Source XOR Destination IP address
 

This is how to change the switch configuration (IOS):

Switch(config)#port-channel load-balance src-dst-ip

With the Cisco IOS Software Release 12.2(33)SXH6 and above, there is an option for PFC3C mode chassis to exclude VLAN in the Load-distribution. Use the port-channel load-balance src-dst-ip exclude vlan command in order to implement this feature. This feature ensures that traffic that belongs to a LAP enters on the same port.

LAG while using VSS, or stacked switch (3750/2960) or Nexus VPC, should work as long as the fragments of an IP packet are sent to the same port. The idea is that if you go to multiple switches, the ports must belong to the same L2 “entity” with regard to load balancing decisions.

To connect the WLC to more than one switch, you must create an AP manager for each physical port and disable LAG. This provides redundancy and scalability.

Whenever avoidable, do not create a backup port for an AP-manager interface, even if it is allowed in older software versions. The redundancy is provided by the multiple AP-manager interfaces as mentioned earlier in this document.

Use Multicast Forwarding Mode

Use multicast forwarding mode for the best performance with less bandwidth utilization. Networks with large IPV6 client counts, heavy multicast application such as Video Streaming, or Bonjour without mDNS proxy, would benefit greatly with multicast mode.

This is how to verify the multicast mode on the controller:

(Cisco Controller) >show network summary

RF-Network Name............................. rfdemo
Web Mode.................................... Enable
Secure Web Mode............................. Enable
Secure Web Mode Cipher-Option High.......... Disable
Secure Web Mode Cipher-Option SSLv2......... Disable
Secure Web Mode RC4 Cipher Preference....... Disable
OCSP........................................ Disabled
OCSP responder URL..........................
Secure Shell (ssh).......................... Enable
Telnet...................................... Enable
Ethernet Multicast Forwarding............... Enable
Ethernet Broadcast Forwarding............... Enable
 

IPv4 AP Multicast/Broadcast Mode............ Multicast Address : 239.0.1.1

IGMP snooping............................... Enabled
IGMP timeout................................ 60 seconds
IGMP Query Interval......................... 20 seconds
MLD snooping................................ Enabled
 

This is how to configure multicast-multicast operations on the WLC command line:

(Cisco Controller) >config network multicast mode multicast 239.0.1.1

(Cisco Controller) >config network multicast global enable

  • The multicast address is used by the controller in order to forward traffic to Access Points. It is important that the multicast address does not match another address in use on your network by other protocols. For example, if you use 224.0.0.251, it breaks mDNS used by some third party applications. Cisco recommends that the address be in the private range (239.0.0.0-239.255.255.255, which does not include 239.0.0.x and 239.128.0.x). It is also important that the multicast IP address be set to a different value on each WLC. You do not want a WLC that speaks to its Access Points to reach the APs of another WLC.
  • If the Access points are on a different subnetwork than the one used on the management interface, your network infrastructure must provide multicast routing between the management interface subnet and the AP subnetwork.

Disable Internal DHCP

The controller has the ability to provide internal DHCP server. This feature is very limited and considered as convenience that is often used simple demonstration or proof-of-concept, for example in a lab environment. The best practice is NOT to use this feature in an enterprise production network.

To show if an internal DHCP server is used, this can be found in the interface configuration, where Primary DHCP server address is the same as the management IP address, an example is shown below:

(Cisco Controller) >show dhcp summary

Interface Name................................... management
MAC Address...................................... e0:2f:6d:5c:f0:40
IP Address....................................... 10.10.10.2
IP Netmask....................................... 255.255.255.0
IP Gateway....................................... 10.10.10.1
External NAT IP State............................ Disabled
External NAT IP Address.......................... 0.0.0.0
Link Local IPv6 Address.......................... fe80::e22f:6dff:fe5c:f040/64
STATE ........................................... NONE
Primary IPv6 Address............................. ::/128
STATE ........................................... NONE
Primary IPv6 Gateway............................. ::
Secondary IPv6 Address........................... ::/128
STATE ........................................... NONE
Secondary IPv6 Gateway........................... ::
VLAN............................................. 10
Quarantine-vlan.................................. 0
Active Physical Port............................. 1
Primary Physical Port............................ 1
Backup Physical Port............................. Unconfigured
DHCP Proxy Mode.................................. Global
Primary DHCP Server.............................. 10.10. 10.2
 

Change the internal DHCP server (management IP address) to a production DHCP server:

(Cisco Controller) >config interface dhcp management primary <primary-server>

A good housekeeping may also be to disable/clean up existing internal DHCP scopes; first, confirm internal DHCP scope:

(Cisco Controller) >show dhcp summary

Scope Name Enabled Address Range
Scope1 Yes 10.10.10.100 -> 10.10.10.150
Either disable the scope:
 

(Cisco Controller) >config dhcp delete-scope <scope name>

or

(Cisco Controller) >config dhcp disable <scope name>

Security

Following are the best practices for security:

Disable Local EAP

Local EAP is an authentication method that allows users and wireless clients to be authenticated locally on the controller. Similar to internal DHCP feature, in which local EAP is also considered a convenience feature intended for simple demonstration or proof-of-concept in a lab environment. Using local EAP in an enterprise production environment is not recommended, the best practice is to disable or avoid using local EAP.

To check if a WLAN is configured to use local EAP:

(Cisco Controller) >show wlan <WLAN id>

Radius Servers
Authentication................................ Global Servers
Accounting.................................... Global Servers
Interim Update............................. Disabled
Framed IPv6 Acct AVP ...................... Prefix
Dynamic Interface............................. Disabled
Dynamic Interface Priority.................... wlan
Local EAP Authentication......................... Disabled
Radius NAI-Realm................................. Disabled
 

To disable local authentication on a WLAN:

(Cisco Controller) >config wlan local-authen disable <WLAN id>

WPA2 + 802.1X WLAN

Although the controller and Access points do support WLAN with SSID using WiFi Protected Access (WPA) and WPA2 simultaneously, it is very common that some wireless client drivers cannot handle complex SSID settings. Whenever possible, Cisco recommends WPA2 only with Advanced Encryption Standard (AES). However due to standards and mandatory WiFi Alliance certification process, TKIP support is required across future software versions. Keep the security policies simple for any SSID such as a separate WLAN/SSID with WPA and Temporal Key Integrity Protocol (TKIP), and a separated one with WPA2 and Advanced Encryption Standard (AES). Since TKIP is being deprecated, Cisco recommends to use TKIP together with WEP, or migrate out of TKIP completely and use PEAP if possible.

This is how to create a WLAN with WPA2 and 802.1X enabled:

(Cisco Controller) >config wlan security wpa enable <WLAN id>

Configure RADIUS authentication server on specified WPA2/802.1X WLAN:

(Cisco Controller) >config wlan radius_server auth add <WLAN id> <Server id>

Configure RADIUS accounting server on specified WPA2/802.1X WLAN:

(Cisco Controller) >config wlan radius_server acct add <WLAN id> <Server id>

Identity Design Tip - Use AAA Override

If designing for identity based networking services, where the wireless clients should be separated in several sub-networks for security reasons, such as each one with different security policies, use one or two WLANs together with the AAA-Override feature. AAA-Override feature allows you to assign per user settings. For example, move the user to either a specific dynamic interface in a separated VLAN or apply a per user Access Control List (ACL).

This is how to configure:

(Cisco Controller) >config wlan aaa-override enable <WLAN id>

Confirm WLAN configuration:

(Cisco Controller) >show wlan <WLAN id>

WLAN Identifier.................................. 1
Profile Name..................................... WLAN-1
Network Name (SSID).............................. WLAN-1
Status........................................... Disabled
MAC Filtering.................................... Disabled
Broadcast SSID................................... Enabled
AAA Policy Override.............................. Enabled
Network Admission Control
Security
802.11 Authentication:........................ Open System
FT Support.................................... Disabled
Static WEP Keys............................... Disabled
802.1X........................................ Disabled
Wi-Fi Protected Access (WPA/WPA2)............. Enabled
WPA (SSN IE)............................... Disabled
WPA2 (RSN IE).............................. Enabled
TKIP Cipher............................. Disabled
AES Cipher.............................. Enabled
Auth Key Management
802.1x.................................. Enabled
PSK..................................... Disabled
CCKM.................................... Disabled
..
FT-1X(802.11r).......................... Disabled
FT-PSK(802.11r)......................... Disabled
PMF-1X(802.11w)......................... Disabled
Radius Servers
Authentication................................ 10.10.10.60 1812
Accounting.................................... 10.10.10.60 1813
Interim Update............................. Disabled
Framed IPv6 Acct AVP ...................... Prefix
Dynamic Interface............................. Disabled

Use Faster RADIUS Timeout

For 802.1x, it is recommended to have the lowest configured RADIUS timeout as possible for a big or busy network. Since the longer the timeout is defined, the longer a frame re-transmission for the queue for RADIUS is held. Depending on the capacity of the network, and how busy the queue may be, a longer timeout may increase chance of retransmission failure rate. It may take longer to discover that a radius server is down with a longer timeout. For most network deployment with high authentication count, a smaller timeout is better to improve capacity handling in the controller. Smaller timeouts can also make the WLC to recover faster from an unresponsive radius server. However, for Radius NAC (ISE) and Radius over slow WAN, it is recommended to have a longer timeout (5 seconds).

The following example shows a default of 2 seconds that may be acceptable for a fast RADIUS fail over, but probably not enough for Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) authentication. If the RADIUS server has to contact external databases (Active Directory, NAC, SQL, and so forth) then come back within the specified timeout period.

This is how to verify:

(Cisco Controller) >show radius summary

Vendor Id Backward Compatibility................. Disabled
Call Station Id Case............................. lower
Acct Call Station Id Type........................ Mac Address
Auth Call Station Id Type........................ AP's Radio MAC Address:SSID
Aggressive Failover.............................. Enabled
Keywrap.......................................... Disabled

Authentication Servers

Idx Type Server Address Port State Tout RFC3576
--- ---- ---------------- ------ -------- ---- -------
1 N 10.48.76.50 1812 Enabled 2 Enabled

IPSec -AuthMode/Phase1/Group/Lifetime/Auth/Encr
------------------------------------------------
Disabled - none/unknown/group-0/0 none/none
 

This is how to configure:

(Cisco Controller) >config radius auth retransmit-timeout 1 <seconds>

EAP Identity Request Timeout

In the controllers, the default timeout for the EAP Identity request may need to increase for some situations similar to when implementing One Time Passwords (OTP) on Smart Card, where the user interaction is needed in answering the identity request. In autonomous Access points the default timeout is 30 seconds. Consider this while migrating autonomous to infrastructure wireless networks.

To show default timeouts use this command:

(Cisco Controller) >show advanced eap

EAP-Identity-Request Timeout (seconds)........... 30
EAP-Identity-Request Max Retries................. 2
EAP Key-Index for Dynamic WEP.................... 0
EAP Max-Login Ignore Identity Response........... enable
EAP-Request Timeout (seconds).................... 30
EAP-Request Max Retries.......................... 2
EAPOL-Key Timeout (milliseconds)................. 1000
EAPOL-Key Max Retries............................ 2
EAP-Broadcast Key Interval....................... 3600
 

This is how to change timeout (seconds):

(Cisco Controller) >config advanced eap identity-request-timeout <seconds>

EAPoL Key Timeout and Max Retries

Recommended EAPol timeout to be as small as possible for voice clients, such as IP 7920 phones. Max retries should be increased if RF environment is operating less than optimum.

(Cisco Controller) >show advanced eap

EAP-Identity-Request Timeout (seconds)........... 30
EAP-Identity-Request Max Retries................. 2
EAP Key-Index for Dynamic WEP.................... 0
EAP Max-Login Ignore Identity Response........... enable
EAP-Request Timeout (seconds).................... 30
EAP-Request Max Retries.......................... 2
EAPOL-Key Timeout (milliseconds)................. 1000
EAPOL-Key Max Retries............................ 2
EAP-Broadcast Key Interval....................... 3600

Configure EAPoL timeout:

(Cisco Controller) >config advanced eap eapol-key-timeout <milliseconds>

To configure EAPo retry counts:

(Cisco Controller) >config advanced eap eapol-key-retries <retries>

EAP Request Timeout and Max Retries

Depending on client types, some slow devices may not work with very fast times, but for the rest, it can be beneficial to have shorter timeout, and longer retry count for faster recovery on bad RF environments. This is also applicable to clients authenticating with inner EAP method such as PEAP/GTC.

To show default timeouts use this command:

(Cisco Controller) >show advanced eap

EAP-Identity-Request Timeout (seconds)........... 30
EAP-Identity-Request Max Retries................. 2
EAP Key-Index for Dynamic WEP.................... 0
EAP Max-Login Ignore Identity Response........... enable
EAP-Request Timeout (seconds).................... 30
EAP-Request Max Retries.......................... 2
EAPOL-Key Timeout (milliseconds)................. 1000
EAPOL-Key Max Retries............................ 2
EAP-Broadcast Key Interval....................... 3600
 

To configure EAP Request timeout:

(Cisco Controller) >config advanced eap request-timeout <seconds>

 

To configure EAP Request retry counts:

(Cisco Controller) >config advanced eap request-retries <retries>

CCKM Timestamp Validation

Change CCKM validation to 5 seconds to avoid pico-cells or roaming issues:

(Cisco Controller) >config wlan security wpa akm cckm timestamp-tolerance 5000 <WLAN id>

TACACS+ Management Timeout

It is best practices to increase the retransmit timeout value for TACACS+ authentication, authorization, and accounting servers if you experience repeated re-authentication attempts or the controller falls back to the backup server when the primary server is active and reachable. This is especially true when implementing for use with One Time Password (OTP).

(Cisco Controller) >show tacacs summary

Authentication Servers

Idx Server Address Port State Tout MgmtTout
--- ---------------------- ------ ------- ----- --------
1 10.10.10.60 49 Enabled 5 2
Authorization Servers
Idx Server Address Port State Tout MgmtTout
--- ---------------------- ------ ------- ----- --------
1 10.10.10.60 49 Enabled 5 2
 

To configure TACACS+ authentication retransmit timeout:

(Cisco Controller) >config tacacs auth server-timeout 1 <seconds>

To configure TACACS+ authorization retransmit timeout:

(Cisco Controller) >config tacacs athr server-timeout 1 <seconds>

Enable Infrastructure and Client Management Frame Protection (MFP)

Infrastructure and client Management Frame Protection (MFP) can be used to validate all 802.11 management traffic detected between nearby Access points in the wireless infrastructure to prevent spoofing. Note enabling infrastructure MFP may generate lots of traps, and client MFP requires CCXv5 support. The evolution is to move to IEEE standard based 802.11w with support available on more recent clients such as Windows 8.


Note The interoperability between various manufacturers are being continuously updated to take advantage of CCXv5 support.


This is how to enable infrastructure MFP (globally):

(Cisco Controller) >config wps mfp infrastructure enable

This is how to enable client MFP (per WLAN):

(Cisco Controller) >config wlan mfp client enable <WLAN id>

Enable 802.11w Support

The 802.11w standard for PMF(Protected Management Frame) is implemented since 7.4 release, which applies only to a set of robust management frames that are protected by the PMF service.

This is how to enable 802.11w (PSK enabled WLAN):

(Cisco Controller) >config wlan security wpa akm pmf psk enable <WLAN id>

This is how to enable 802.11w (802.1x enabled WLAN):

(Cisco Controller) >config wlan security wpa akm pmf 802.1x enable <WLAN id>

Change SNMPv3 Default User

Check on the SNMPv3 default user. By default, the controller comes with a username that should be disabled or changed.

This is how to verify:

(Cisco Controller) >show snmpv3user

SNMP v3 User Name AccessMode Authentication Encryption
-------------------- ----------- -------------- ----------
default Read/Write HMAC-SHA CFB-AES

This is how to configure:

(Cisco Controller) >config snmp v3user delete default

(Cisco Controller) >config snmp v3user create nondefault rw hmacsha des authkey <encrypkey12characters>


Note Ensure that your SNMP settings must match between the controller and the Wireless Control System (WCS)/Network Control System(NCS)/Prime Infrastructure (PI). Also, you should use encryption and hash keys that match your security policies.


Enable Network Time Protocol (NTP)

Network Time Protocol (NTP) is very important for several features. It is mandatory to use NTP synchronization on controllers if you use any of these features: Location, SNMPv3, Access point authentication, or MFP. The WLC will support synchronization with NTP using authentication.

This is how to enable NTP server:

(Cisco Controller) >config time ntp server 1 10.10.10.1

In order to verify, check for entries like this in your traplog:

30 Mon Jan 6 08:12:03 2014 Controller time base status - Controller is in sync with the central timebase.

This is how to enable NTP authentication:

(Cisco Controller) >config time ntp auth enable <ntp server index>

(Cisco Controller) >config time ntp key-auth add <key index>

Enable 802.11r Fast Transition

802.11r is the IEEE standard for fast roaming, a concept of roaming where the initial authentication handshake with the target AP (i.e., the next AP that the client intends to connect to) is done even before the client associates to the target AP, which is called Fast Transition (FT). By default, fast transition is disabled.


Note Non 802.11r clients will not be able to connect to this wlan, make sure the clients are 802.11r capable, examples are Apple devices on version 6 and above.


This is how to enable 802.11r or Fast Transition (FT):

(Cisco Controller) >config wlan security ft enable <WLAN id>

This is how to configure FT authentication management using 802.1X:

(Cisco Controller) >config wlan security wpa akm ft-802.1X enable <WLAN id>

This is how to configure FT authentication management using PSK:

(Cisco Controller) >config wlan security wpa akm ftp-psk enable <WLAN id>

DHCP Required Option

For enhanced security, Cisco recommends that you require all clients to obtain their IP addresses from a DHCP server.

The DHCP Required option in WLAN settings allows you to force clients to do a DHCP address request/renew every time they associate to the WLAN before they are allowed to send or receive other traffic to the network. From a security standpoint, this allows for a more strict control of IP addresses in use. But also might have an effect in the total time for roaming before traffic is allowed to pass again.

Additionally, this might affect some client implementations that do not do a DHCP renew until the lease time expires. This depends on the client types, for example, Cisco 7921 or 7925 phones might have voice problems while they roam if this option is enabled, as the controller does not allow voice or signaling traffic to pass until the DHCP phase is completed. Another example may include Android and some Linux distributions that only do DHCP renew on half the length of the lease time, not on roaming; this may be a problem if client expires.

Some third-party printer servers might also be affected. In general, it is a good idea not to use this option if the WLAN has non-Windows clients. This is because the more strict controls might induce connectivity issues, based on how the DHCP client side is implemented.

This is how you verify:

(Cisco Controller) >show wlan <WLAN id>

WLAN Identifier.................................. 1
Profile Name..................................... WLAN-1
Network Name (SSID).............................. WLAN-1
Status........................................... Enabled
MAC Filtering.................................... Disabled
mDNS Status...................................... Enabled
mDNS Profile Name................................ default-mdns-profile
DHCP Server...................................... Default
DHCP Address Assignment Required................. Enabled

Rogue Management

Rogue wireless devices are an ongoing threat to corporate wireless networks. Network owners need to do more than just scan for unknown devices: they must be able to detect, disable, locate and manage rogue/intruder threats automatically and in real time.

Rogue Access points can disrupt wireless LAN operations by hijacking legitimate clients and using plain text or other denial-of-service or man-in-the-middle attacks. That is, a hacker can use a rogue Access point to capture sensitive information, such as passwords and usernames. The hacker can then transmit a series of clear-to-send (CTS) frames, which mimics an Access point informing a particular wireless LAN client adapter to transmit and instructing all others to wait. This scenario results in legitimate clients being unable to access the wireless LAN resources. Thus, wireless LAN service providers have a strong interest in banning rogue Access points from the air space.

This is how to verify:

(Cisco Controller) >show rogue ap summary

Rogue Detection Security Level................... custom
Rogue Pending Time............................... 180 secs
Rogue on wire Auto-Contain....................... Disabled
Rogue using our SSID Auto-Contain................ Disabled
Valid client on rogue AP Auto-Contain............ Disabled
Rogue AP timeout................................. 1200
Rogue Detection Report Interval.................. 10
Rogue Detection Min Rssi......................... -128
Rogue Detection Transient Interval............... 0
Rogue Detection Client Num Thershold............. 0
Total Rogues(AP+Ad-hoc) supported................ 2000
Total Rogues classified.......................... 41
MAC Address Classification # APs # Clients Last Heard
----------------- ------------------ ----- --------- -----------------------
00:0d:67:1e:7c:a5 Unclassified 1 0 Thu Feb 6 22:04:38 2014
00:0d:67:1e:7c:a6 Unclassified 1 0 Thu Feb 6 22:04:38 2014
00:0d:67:1e:7c:ac Unclassified 2 0 Thu Feb 6 22:04:38 2014

Rogue Detection

There are good reasons to use rogue detection to minimize security risks, such as in a corporate environment. However, there are certain scenarios in which rogue detection is not needed, for example in OEAP deployment, open venues/stadium, citywide and outdoors. Using outdoor mesh APs to detect rogues would provide little value while incurring resources to analyze. Finally, it is critical to evaluate (or avoid altogether) rogue auto-containment, as there are potential legal issues and liabilities if left to operate automatically.

To verify rogue detection on AP:

(Cisco Controller) >show ap config general <AP Name>

Cisco AP Identifier.............................. 4
Cisco AP Name.................................... AP1140
Country code..................................... Multiple Countries:PT,US
Regulatory Domain allowed by Country............. 802.11bg:-AE 802.11a:-AE
AP Country code.................................. US - United States
AP Regulatory Domain............................. 802.11bg:-A 802.11a:-A
..
AP Link Latency.................................. Disabled
Rogue Detection.................................. Enabled
 

To enable rogue detection on an AP:

(Cisco Controller) >config rogue detection enable <Cisco AP>

Min-RSSI

A rogue with a weak RSSI does not provide any valuable information to the network administrator other than it has been heard. A rogue with a weak RSSI also poses less of a threat to the wireless network than a rogue with a stronger signal. Too many weak signaled rogues could clutter the Prime Infrastructure GUI, making rogue mitigation difficult. This can now be avoided by limiting the minimum RSSI value (Minimum RSSI for Rogue Classification) that the AP needs to report the rogue at.

To configure rogue detection based on minimum RSSI of -70dBm:

(Cisco Controller) >config rogue detection min-rssi -70

Configure rogue detection security level to low (no auto-containment):

(Cisco Controller) >config rogue detection security-level low

Rogue Rules

Create a rogue rule for additional conditions set. For example, create ‘rule1’:

(Cisco Controller) >config rogue rule add ap priority 1 classify malicious notify all state alert rule1

Activate the rule:

(Cisco Controller) >config rogue rule enable rule1

To verify rule summary:

(Cisco Controller) >show rogue rule summary

Priority Rule Name Rule state Class Type Notify State Match Hit Count
-------- -------------------------------- ----------- ----------- -------- -------- ------ ---------
1 rule1 Enabled Malicious All Alert Any 0

Up to 6 conditions can be added to a Rogue Rule.

Adding condition based rules can help to easily detect people spoofing on your network. To configure condition rule based on a managed SSID:

(Cisco Controller) >config rogue rule condition ap set managed-ssid rule1

Add condition based on specific SSID name:

(Cisco Controller) >config rogue rule condition ap set ssid <SSID_name> rule1

Add condition based on minimum RSSI, for example, -70dBm:

(Cisco Controller) >config rogue rule condition ap set rssi -70 rule1

Add condition based on duration (in seconds) the rogue has been detected, for example, 120 seconds:

(Cisco Controller) >config rogue rule condition ap set duration 120 rule1

Confirm rogue rule conditions:

(Cisco Controller) >show rogue rule detailed rule1

Priority......................................... 1
Rule Name........................................ rule1
State............................................ Disabled
Type............................................. Malicious
Notify........................................... All
State ........................................... Alert
Match Operation.................................. Any
Hit Count........................................ 0
Total Conditions................................. 3
Condition 1
type......................................... Duration
value (seconds).............................. 120
Condition 2
type......................................... Managed-ssid
value........................................ Enabled
Condition 3
type......................................... Rssi
value (dBm).................................. -70

Wi-Fi Direct

Wi-Fi Direct allows Wi-Fi devices to make direct connections to one another quickly and conveniently like printing, synchronizing, and sharing content. A security concern can arise for the wireless network if the device is connected to both the infrastructure and a Personal Area Network (PAN) at the same time. Cisco recommends to disallow Wi-Fi direct clients to prevent a security hole.

Disallow Wi-Fi direct clients from associating with the WLAN:

(Cisco Controller) >config wlan wifidirect not-allow <WLAN-id>

Channels Scanning for Rogues

For a local/FlexConnect mode/Monitor mode AP there is an option under RRM configuration, which allows the user to choose which channel is scanned for rogues. Depending on the configuration, the AP scans all channel/country channel/DCA channels for rogues. These are the quick explanation on benefits of each:

For higher security, choose all channel.

Choose DCA channels for performance, as system will scan as least as possible

For a balance of performance and security, choose country channel option.

This is an example to configure 5GHz channel scanning for Rogue Detection for all channels:

(Cisco Controller) >config advanced 802.11a monitor channel-list all

This is an example to configure 2.4GHz monitor channel scanning in configured country code:

(Cisco Controller) >config advanced 802.11b monitor channel-list country

Transient Rogue Interval

Using the transient interval values, you can control the time interval at which APs should scan for rogues. APs can also filter rogues based on their transient interval values.

This feature has the following advantages:

 Rogue reports from APs to the controller are shorter.

 Transient rogue entries are avoided in the controller.

Unnecessary memory allocation for transient rogues is avoided.

Configure transient rogue interval of 2mins (120 seconds):

(Cisco Controller) >config rogue detection monitor-ap transient-rogue-interval 120

Enable Adhoc Rogue Detection

Similar to general rogue detection, adhoc rogue detection may be ideal in certain scenarios, such as corporate where security is justifiable. However in scenarios such as open venues/stadiums, citywide and public outdoors is not of value.

Enable ad hoc rogue detection and reporting by entering this command:

(Cisco Controller) >config rogue adhoc enable

Enable Rogue Clients AAA Validation

A good reason to enable AAA validation for rogue clients is so that the WLC will reliably and continuously checking for a client to exist on the AAA server, then marking it either valid or malicious.

(Cisco Controller) >config rogue client aaa enable

Enable Rogue Clients MSE Validation

If there is a Mobility Services Engine (MSE) is available and integrated, it can share information in its learned clients database to compliment the WLC in validating whether a client is valid or a threat.

Enable the use of MSE (if available) to check if rogue clients are valid:

(Cisco Controller) >config rogue client mse enable

Wireless/RF

For any wireless deployment, always do a proper site survey in order to ensure proper quality of service for your wireless clients. The requirements for voice or location deployments are stricter than for data services. Auto RF might help on channel and power settings management, but it cannot correct a bad RF design.

The site survey must be done with devices that match the power and propagation behavior of the devices to be used on the real network. For example, do not use an older 802.11b/g radio with omni antenna to study coverage if the final network uses more modern dual radios for 802.11a/b/g with n and 802.11ac data rates.

The site survey should be done with the AP model that the customer is going to install. The AP should be at the orientation and height that will be typical of the final installation. The data rates on the AP should be set to the rates required by the customer application, bandwidth, and coverage requirements. Do not measure the coverage area to a data rate of 1 Mbps with 2.4 GHz. If the primary objective of the network design is for each area of coverage to support 30 users at 5 GHz with 9 Mbps of data rate, then perform a coverage test with the primary network device with only the 5 GHz data rate with 9 Mbps enabled. Then, measure the -67 dBm receive signal strength indicator (RSSI) on the AP for the test network client during active data traffic between the AP and client. High quality RF links have good signal to noise ratios (SNR) and low channel utilization (CU) percentages. RSSI, SNR, and CU values are found on the WLC’s client and AP information pages.

Disable Low Data Rates

You must carefully plan the process to disable or enable data rates. If your coverage is sufficient, it is often a good idea to incrementally disable lower data rates one by one. Management frames like ACK or beacons will be sent at the lowest mandatory rate (typically 1Mbps), which slows down the whole throughput as the lowest mandatory rate consumes the most airtime.

Try not to have too many supported data rates so that clients can down-shift their rate faster when retransmitting. Typically clients try to send at the fastest data rate they can and if the frame does not make it through, will retransmit at the next lowest data rate and so on until the frame goes through. The removal of some supported rates means that clients who retransmit a frame directly down-shift several data rates, which increases the chance for the frame to go through at the second attempt.

Beacons are sent at the lowest mandatory rate, defining roughly the cell size.

Multicast is sent on the range between lowest and highest priority, depending on associated clients.

If your design does not require low data rates, consider disabling the 802.11b data rates (1, 2,5.5 and 11) and leave the rest enabled.

You might make a conscious decision to not disable all rates below 11Mbps in order to not stop the support of 802.11b-only clients.

The following example serves only as an example as it should not be viewed as solely optimal for every design (do not use as strict guideline). These changes are sensitive and heavily dependent on your RF coverage design.

For example, if designing for hotspot, have the lowest enabled, because the goal is to have coverage gain versus speed.

Conversely, if you are designing for a high-speed network, with already good RF coverage, disable the lowest.

Example to disable low data rates (5GHz and 2.4GHz):

(Cisco Controller) >config 802.11a disable network

(Cisco Controller) >config 802.11a 11nSupport enable

(Cisco Controller) >config 802.11a rate disabled 6

(Cisco Controller) >config 802.11a rate disabled 9

(Cisco Controller) >config 802.11a rate disabled 12

(Cisco Controller) >config 802.11a rate disabled 18

(Cisco Controller) >config 802.11a rate mandatory 24

(Cisco Controller) >config 802.11a rate supported 36

(Cisco Controller) >config 802.11a rate supported 48

(Cisco Controller) >config 802.11a rate supported 54

(Cisco Controller) >config 802.11a enable network

(Cisco Controller) >config 802.11b disable network

(Cisco Controller) >config 802.11b 11gSupport enable

(Cisco Controller) >config 802.11b 11nSupport enable

(Cisco Controller) >config 802.11b rate disabled 1

(Cisco Controller) >config 802.11b rate disabled 2

(Cisco Controller) >config 802.11b rate disabled 5.5

(Cisco Controller) >config 802.11b rate disabled 11

(Cisco Controller) >config 802.11b rate disabled 6

(Cisco Controller) >config 802.11b rate disabled 9

(Cisco Controller) >config 802.11b rate supported 12

(Cisco Controller) >config 802.11b rate supported 18

(Cisco Controller) >config 802.11b rate mandatory 24

(Cisco Controller) >config 802.11b rate supported 36

(Cisco Controller) >config 802.11b rate supported 48

(Cisco Controller) >config 802.11b rate supported 54

(Cisco Controller) >config 802.11b enable network

Lower the Number of SSIDs

Cisco recommends to limit the number of service set identifiers (SSIDs) configured at the controller. You can configure 16 simultaneous SSIDs (per radio on each Access point (AP)), but as each WLAN/SSID needs separate probe responses and beaconing, the RF pollution increases as more SSIDs are added. Furthermore, some smaller wireless stations like PDA, WiFi Phones, and barcode scanners cannot cope with a high number of basic SSID (BSSID) information. This results in lockups, reloads, or association failures. Also the more SSIDs, the more beaconing needed, so less RF time is available for real data transmits. For example, the recommendation is to have 1 to 3 SSIDs for corporate, and 1 SSID for high-density designs. AAA override can be leveraged for per user VLAN/ settings on a single SSID scenario.

Enter this command in order to verify:

(Cisco Controller) >show wlan summary

Number of WLANs.................................. 8
WLAN ID WLAN Profile Name / SSID Status Interface Name
------- ------------------------------------- -------- --------------------
1 WLAN-Local / WLAN-Local Enabled management
2 WLAN-Lync / WLAN-Lync Enabled Lync
3 WLAN-AVC / WLAN-AVC Enabled AVC
4 WLAN-11ac / WLAN-11ac Enabled 11ac
5 WLAN-Visitor / WLAN-Visitor Enabled Visitor
6 WLAN-1X / WLAN-1X Enabled 1X
7 WLAN-23 / WLAN-23 Enabled 23
8 WLAN-HS2 / WLAN-HS2 Enabled HS2

Disable unnecessary SSIDs:

(Cisco Controller) >config wlan disable 8

(Cisco Controller) >config wlan disable 7

(Cisco Controller) >config wlan disable 6

(Cisco Controller) >config wlan disable 5

Enable Band Selection

Band selection enables client radios that are capable of dual-band (2.4 and 5 GHz) operation to move to a less congested 5 GHz Access point. The 2.4 GHz band is often congested. Clients on this band typically experience interference from Bluetooth devices, microwave ovens, and cordless phones as well as co-channel interference from other Access points because of the 802.11b/g limit of three non-overlapping channels. To prevent these sources of interference and improve overall network performance, you can configure band selection on controller:

Band selection is enabled/disabled globally by default.

Band selection works by regulating probe responses to clients. It makes 5-GHz channels more attractive to clients by delaying probe responses to clients on 2.4-GHz channels.

Evaluate band selection for voice, particularly focusing on roaming performance, see below for further explanation.

Most newer model clients prefer 5 GHz by default if the 5 GHz signal of the AP is equal to or stronger than the 2.4 GHz signal.

Band select should be enabled for high-density designs.

Also, in high-density designs the study of available UNII-2 channels should be made. Those channels that are unaffected by Radar and also usable by the client base should be added to the RRM DCA list as usable channels.

Dual-band roaming can be slow depending on the client. If a majority of the base of voice clients exhibits a slow roaming behavior, it is more likely that the client sticks to 2.4 GHz, in that case, it has scanning issues on 5 GHz. Generally when a client decides to roam, it scans its current channel and band first. The clients generally scan for an AP that has a significantly better signal level, maybe as much as 20 dB and/or a significantly better SNR. Failing such available connection, the client may remain with its current AP. In this case if the CU on 2.4 GHz is low and the call quality is not poor, then disabling the selected band maybe fine. However, the preferred design is to enable band selection on 5 GHz with all data rates enabled and 6 Mbps as mandatory. Then, set the 5 GHz RRM minimum Tx power level 6 dBm higher than the average 2.4 GHz power level set by RRM.

The goal of this configuration recommendation is to enable the client to obtain a band and channel with better SNR and Tx power initially. As already stated, generally when a client decides to roam, it scans its current channel and band first. So, if the client initially joins the 5 GHz band, then it is more likely to stay on the band if there are good power levels on 5 GHz. SNR levels on 5 GHz are generally better than 2.4 GHz because 2.4 GHz has only three Wi-Fi channels and is more susceptible to interference such as Bluetooth, iBeacons, and microwave signals.

802.11k is recommended to be enabled with dual-band reporting. This enables all 11k enabled clients to have the benefit of assisted roaming. With dual-band reporting enabled, the client receives a list of the best 2.4 and 5 GHz APs upon a directed request from the client. Here, the client most likely looks at the top of the list for an AP on the same channel, and then on the same band as the client is currently on. This logic reduces scan times and saves battery power. Having 802.11k enabled on the WLC does not have a downside effect for non-802.11k clients.

Enter this command in order to verify:

(Cisco Controller) >show band-select

Band Select Probe Response....................... per WLAN enabling
Cycle Count................................... 2 cycles
Cycle Threshold............................... 200 milliseconds
Age Out Suppression........................... 20 seconds
Age Out Dual Band............................. 60 seconds
Client RSSI................................... -80 dBm
 

Enable or disable band selection on specific WLANs:

(Cisco Controller) >config wlan band-select allow enable <WLAN id>

DCA – Dynamic Channel Assignment

When a wireless network is first initialized, all radios participating require a channel assignment in order to operate without interference – optimizing the channel assignments to allow for interference free operation is DCA’s job. Wireless network does this using the air metrics reported by each radio on every possible channel, and providing a solution that maximizes channel bandwidth and minimizes RF interference from all sources – Self (signal), other networks (foreign interference), Noise (everything else).

DCA is enabled by default and provides a global solution to channel planning for your network.

  • Let RRM automatically configure all 802.11a or 802.11b/g channels based on availability and interference:

(Cisco Controller) >config 802.11a channel global auto

(Cisco Controller) >config 802.11b channel global auto

Channel Widths

802.11n can operate in a 40 MHz channel by bonding two 20 MHz channels together and this significantly increases throughput. Not all 802.11n devices support 40 MHz bonded channels (clients). 802.11ac allows for bonding of 20 MHz channels into an 80 MHz wide channel for 802.11ac usage, and all Clients must support 80 MHz. This is not practical for 2.4 GHz as there are a very limited number of non overlapping 20 MHz channels available. However, in 5 GHz this can represent a significant increase in throughput and speed provided you have enough 20 MHz channels (see DFS below).

Use this command to set DCA assigned channel width to all capable radios.

(Cisco Controller) config advanced 802.11a channel dca chan-width-11n <20 | 40 |80> 

Channel width overview:

 20 permits the radio to communicate using only 20-MHz channels. Choose this option for legacy 802.11a radios, 20-MHz 802.11n radios, or 40-MHz 802.11n radios that you want to operate using only 20-MHz channels. This is the default value.

 40 permits 40-MHz 802.11n radios to communicate using two adjacent 20-MHz channels bonded together. The radio uses the primary channel that you choose as the anchor channel (for beacons) as well as its extension channel for faster data throughput. Each channel has only one extension channel (36 and 40 are a pair, 44 and 48 are a pair, and so on). For example, if you choose a primary channel of 44, the Cisco WLC would use channel 48 as the extension channel. If you choose a primary channel of 48, the Cisco WLC would use channel 44 as the extension channel.

80  sets the channel width for the 802.11ac radios to 80 MHz. 


Note Statically configuring an Access point’s radio for 20-MHz, 40-MHz or 80-MHz mode overrides the globally configured DCA channel width setting configured using the config advanced 802.11a channel dca chan-width-11n {20 | 40 |80} command. If you ever change the static configuration back to global on the Access point radio, the global DCA configuration overrides the channel width configuration that the Access point was previously using. Change takes effect within 30 minutes depending on how often DCA is configured to run.



Note Channels 116,120, 124, and 128 are not available in the U.S. and Canada for 40-MHz channel bonding


DFS – Dynamic Frequency Selection

Not all channels are created at once. Dynamic Frequency Selection was created to increase the availability of more channels in the 5 GHz spectrum. Depending on regulatory domain this can mean from 4 to 12 additional channels. More channels implies more capacity.

DFS detects radar signals and ensures that there is no interference with weather radar that may be operating on our frequency. The DFS specification also designates the Master (our AP) as the monitor for the group that will steer clients and the AP away from any signals that are detected. Traditionally there has been some misgivings in North America about using DFS channels – but then we have 8 that are not DFS. In the ETSI regulatory domain (Europe) – they have 4 non DFS channels and have been using DFS channels successfully for many years.

Although the 5GHz band offers more channels, care should be given in the overall design as the 5GHz channels have varying power and indoor/outdoor deployment restrictions. For example, in North America, the U-NII-1 can only be used indoors and it has power restriction of 50mW maximum power, both U-NII-2 and U-NII-2e are subject to Dynamic Frequency Selection).

 

  • By default U-NII-2e channels are disabled in the DCA channel list. Check what channels are being used using this command.

(Cisco Controller) show>advanced 802.11a channel

<snip>

802.11a 5 GHz Auto-RF Channel List

Allowed Channel List..36,40,44,48,52,56,60,64,149,153,157,161

Unused Channel List..100,104,108,112,116,120,124,128,132,136,140,165

DCA Outdoor AP option.......................... Disabled

Enable the U-NII-2e channels for more channels in your regulatory domain using this command.

(Cisco Controller) >config advanced 802.11a channel add <channel>

Available channels in North America and Europe are 100-140 (8 additional channels). Channels 120, 124, 128 are disabled in the US, and severely penalized in ETSI DFS rules and are not supported.

DCA Restart

Once you have made selections for channels and channel widths, or in the case of a new network completed installing all APs, DCA will manage the channels dynamically and make adjustments as needed over time and changing conditions. However if this is a new installation, or you have made major changes to DCA such as changing channel widths or adding new APs, then you can restart the DCA process which initializes an aggressive search mode (startup), and provides an optimized starting channel plan.

In order to determine which WLC is currently the group leader run this command –

(Cisco Controller) >show advanced 802.11a group

(Cisco Controller) >show advanced 802.11b group

From the identified group leader re-initialize DCA by running this command

(Cisco Controller) >config advanced 802.11a channel global restart

(Cisco Controller) >config advanced 802.11b channel global restart

Verify the restart by running this command -

(Cisco Controller) >show advanced 802.11a channel

<snip>

Last Run Time.................................. 0 seconds
DCA Sensitivity Level.......................... STARTUP (5 dB)
DCA 802.11n/ac Channel Width................... 80 MHz
DCA Minimum Energy Limit....................... -95 dBm

If successful you will see DCA sensitivity showing the STARTUP banner.


Note Startup mode will run for 100 minutes – reaching a solution generally within 30-40 minutes. This can be disruptive to clients (lots of channel changes) if you have made significant changes (channel width, numbers of AP’s). Do this step last – as changes during the startup change the question you are asking.


Application Visibility and Control (AVC)

Application Visibility and Control (AVC) classifies applications using Cisco's Deep Packet Inspection (DPI) techniques with Network-Based Application Recognition (NBAR) engine and provides application-level visibility and control into Wi-Fi network. After recognizing the applications, the AVC feature allows you to either drop or mark the traffic.

Using AVC, the controller can detect more than 1000 applications. AVC enables you to perform real-time analysis and create policies to reduce network congestion, costly network link usage, and infrastructure upgrades.

AVC is supported on the following controller platforms: Cisco 2500 Series Controllers, Cisco 5500 Series Controllers, Cisco Flex 7500 Series Controllers in central switching mode, Cisco 8500 Series Controllers, and Cisco WiSM2.

To enable AVC visibility on a WLAN (for baseline application utilization):

(Cisco Controller) >config wlan avc 1 visibility enable

To show AVC statistics on a WLAN (show application utilization per WLAN):

(Cisco Controller) >show avc statistics wlan <WLAN id>

A general use-case is to mark/drop/rate-limit traffic, such as in this example to prioritize Microsoft Lync traffic for best user experience when making a Lync video/voice call.

To create the AVC profile:

(Cisco Controller) >config avc profile MSLync create

To add one or more rules to the AVC profile (mark Lync Audio with DSCP 46, video with DSCP 34):

(Cisco Controller) >config avc profile MSLync rule add application ms-lync-audio mark 46

(Cisco Controller) >config avc profile MSLync rule add application ms-lync-video mark 34

To apply the AVC profile to a WLAN:

(Cisco Controller) >config wlan avc <WLAN id> profile MSLync

Here is an example to drop Youtube:

(Cisco Controller) >config avc profile DropYoutube rule add application youtube drop

Show AVC profile summary:

(Cisco Controller) >show avc profile summary

Profile-Name Number of Rules
============ ==============
AVC-Profile-1 3
AVC-Profile-2 0
drop-jabber-video 1
MSLync 2
To show the AVC profile detail:
(Cisco Controller) >show avc profile detailed MSLync
Application-Name Application-Group-Name Action DSCP
DIR AVG-RATELIMIT BURST-RATELIMIT
================ ======================= ====== ==== =
==== ============= =============
ms-lync-audio business-and-productivity-tools Mark 46 Bidir
ectional
ms-lync-video business-and-productivity-tools Mark 34 Bidir
ectional
Associated WLAN IDs : 1
Associated Remote LAN IDs :
Associated Guest LAN IDs :

Enable 802.11k for Optimal Roaming

The 802.11k standard allows clients to request neighbor reports containing information about known neighbor Access points that are candidates for a service set transition. The use of the 802.11k neighbor list can limit the need for active and passive scanning.

A common problem 802.11k help to solve is to deal with “sticky clients”, those that seem to associate with a specific AP, and then hold onto that connection so stubbornly even when there are significantly better options available from nearer Access points.

Enable 802.11k neighbor list for a WLAN:

(Cisco Controller) >config wlan assisted-roaming neighbor-list enable <WLAN id>

Enable dual-band 802.11k neighbor list for a WLAN by entering this command:

(Cisco Controller) >config wlan assisted-roaming dual-list enable <WLAN id>

Enable assisted roaming prediction list feature for a WLAN:

(Cisco Controller) >config wlan assisted-roaming prediction enable <WLAN id>

Mobility

These are the best practices for mobility:

  • All controllers in a mobility group should have the same IP address for a virtual interface, for example 192.0.2.x. This is important for roaming. If all the controllers within a mobility group do not use the same virtual interface, inter-controller roaming can appear to work, but the hand-off does not complete and the client loses connectivity for a period of time.

This is how to verify:

(Cisco Controller) >show interface summary

Interface Name Port Vlan Id IP Address Type Ap Mgr
----------------- ----- -------- --------------- ------- ------
ap-manager LAG 15 192.168.15.66 Static Yes
management LAG 15 192.168.15.65 Static No
service-port N/A N/A 10.48.76.65 Static No
test LAG 50 192.168.50.65 Dynamic No
virtual N/A N/A 192.0.2.1 Static No
 
  • The virtual gateway address must be  not routable  inside your network infrastructure. It is only intended to be reachable for a wireless client when connected to a controller, never from a wired connection.
  • IP connectivity must exist between the management interfaces of all controllers.
  • In most situations, all controllers must be configured with the same mobility group name. Exceptions to this rule are deployments on controllers for the Guest Access feature, typically in a Demilitarized Zone (DMZ).
  • The group name is used as a PMK/L2 fast roaming discriminator; for fast roaming design it is required to have the same group name.
  • When deploying for webauth/guest, it is not required to have the same mobility group name.
  • It is a safe trick to run all WLCs on the same software code versions to ensure you do not face inconsistent behaviors due to bugs present on some WLCs and not others. For software Release 6.0 and later, all versions are inter-compatible for mobility purposes so it is not mandatory.
  • Do not create unnecessarily large mobility groups. A mobility group should only have all controllers that have Access points in the area where a client can physically roam, for example all controllers with Access points in a building. If you have a scenario where several buildings are separated, they should be broken into several mobility groups. This saves memory and CPU, as controllers do not need to keep large lists of valid clients, rogues and Access points inside the group, which would not interact anyway.
  • Also, try to accommodate the AP distribution across controllers in the mobility group so that there are APs. For example, per floor or per controller, and not a salt and pepper distribution. This reduces inter-controller roaming, which has less impact on the mobility group activity.
  • In scenarios where there is more than one controller in a mobility group, it is normal to see some rogue Access point alerts about our own Access points in the network after a controller reload. This happens due to the time it takes to update the Access point, client and rogue lists between mobility group members.

Configure Mobility Multicast Mode

Configuring multicast mode for mobility allows the client to announce messages to be sent on multicast between mobility peers, instead of unicast sent to each controller, with benefits on time, CPU usage, and network utilization.


Note Make sure multicast traffic is passing between controllers when their management is on different subnets.


This is how to verify:

(Cisco Controller) >show mobility summary

Mobility Protocol Port........................... 16666
Default Mobility Domain.......................... rfdemo
Multicast Mode .................................. Enabled
Mobility Domain ID for 802.11r................... 0x6569
Mobility Keepalive Interval...................... 10
Mobility Keepalive Count......................... 3
Mobility Group Members Configured................ 2
Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group
MAC Address IP Address Group Name Multicast IP Status
d0:c2:82:dd:66:a0 10.10.10.5 rfdemo 239.0.2.1 Up
 

This is how to configure:

(Cisco Controller) >config mobility multicast-mode enable <local-multicast-address, e.g. 239.0.2.1>

Enable Fast SSID Changing

When fast SSID changing is enabled, the controller allows clients to move faster between SSIDs. When fast SSID is enabled, the client entry is not cleared and the delay is not enforced. This is very important to have for supporting Apple IOS devices.

To enable fast SSID change:

(Cisco Controller) >config network fast-ssid-change enable

Enable CleanAir

To effectively detect and mitigate RF interference, enable CleanAir whenever possible. There are recommendations to various sources of interference to trigger security alerts, such as generic DECT phones, jammer, and so on.

To verify CleanAir configuration on the network (802.11b):

(Cisco Controller) >show 802.11b cleanair config

To verify CleanAir configuration on the network (802.11a):

(Cisco Controller) >show 802.11a cleanair config

Clean Air Solution............................... Disabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
Bluetooth Link........................... Enabled
Microwave Oven........................... Enabled
802.11 FH................................ Enabled
Bluetooth Discovery...................... Enabled
TDD Transmitter.......................... Enabled
 

To enable CleanAir functionality on the 802.11 network:

(Cisco Controller) >config 802.11b cleanair enable network

(Cisco Controller) >config 802.11a cleanair enable network

Configure to enable interference detection for specifically jammer, for example:

(Cisco Controller) >config 802.11b cleanair device enable jammer

To verify CleanAir is enabled on 802.11 network:

(Cisco Controller) >show 802.11a cleanair config

(Cisco Controller) >show 802.11b cleanair config

Clean Air Solution............................... Enabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
TDD Transmitter.......................... Enabled
Jammer................................... Enabled
Continuous Transmitter................... Enabled
DECT-like Phone.......................... Enabled
Video Camera............................. Enabled

Enable High Availability Client/AP SSO

AP Stateful switchover (AP SSO)

High Availability (HA) feature APSSO set within the Cisco Wireless LAN Controller (WLC) network software release version 7.3 and 7.4 allows the Access point (AP) to establish a CAPWAP tunnel with the Active WLC, and share a mirror copy of the AP database with the Standby WLC. The APs do not go into the Discovery state when the Active WLC fails, and the Standby WLC takes over the network as the Active WLC. There is only one CAPWAP tunnel maintained at a time between the APs and the WLC that is in an Active state. The overall goal for the addition of AP SSO support to the Cisco Wireless LAN Controller Network is to reduce major downtime in wireless networks due to failure conditions that may occur due to box fail over or network fail over.

To support High Availability without impacting service, there needs to be support for seamless transition of clients and APs from the active controller to the standby controller. Release 7.5 supports Client Stateful Switch Over (Client SSO) in Wireless LAN controllers. Client SSO will be supported for clients which have already completed the authentication and DHCP phase, and have started passing traffic. With Client SSO, a client information is synced to the Standby WLC when the client associates to the WLC, or when the client parameters change. Fully authenticated clients, the clients in Run state, are synced to the Standby. Thus, client re-association is avoided on switchover making the fail over seamless for the APs as well as for the clients, resulting in zero client service downtime and no SSID outage.


Note Please refer to the Cisco Wireless LAN Controller Configuration Guide for more details.


Before You Begin HA Configuration

Ensure that the management interfaces of both controllers are in the same subnet.

Configure a local redundancy IP address and a peer redundancy management IP address by entering this command:

(Cisco Controller) > config interface address redundancy-management ip-addr1 peer-redundancy-management ip-addr2

Configure the role of a controller by entering this command:

(Cisco Controller) > config redundancy unit {primary | secondary}

Configure the redundancy mode for SSO by entering this command:

(Cisco Controller) > config redundancy mode sso

Both controllers now reboot and then negotiate the roles of active and standby-hot controllers.

Configure the route configurations of the standby controller by entering this command:

(Cisco Controller) > config redundancy peer-route {add network-ip-addr ip-mask | delete network-ip-addr}

This command can be run only if the HA peer controller is available and operational.

Configure the IP address and netmask of the peer service port of the standby controller by entering this command:

(Cisco Controller) > config redundancy interface address peer-service-port ip-address netmask

This command can be run only if the HA peer controller is available and operational.

Initiate a manual switchover by entering this command:

(Cisco Controller) > config redundancy force-switchover

Run this command only when you require a manual switchover.

Configure the redundancy timers by entering this command:

(Cisco Controller) > config redundancy timer {keep-alive-timer time-in-milliseconds | peer-search-timer time-in-seconds}

Configure encryption of communication between controllers by entering this command:

(Cisco Controller) > config redundancy link-encryption {enable | disable}

FlexConnect Best Practices

1. Check to make sure that the AP model being used has FlexConnect Support. Only the following AP models support FlexConnect Mode:

AP-1130, AP-1240, AP-1040, AP-1140, AP-1260, AP-1250, AP-3500, AP-1600, AP-2600, AP-3600, AP-3700, AP-2700, AP-1520, AP-1530, AP-1550

2. The decision to deploy a distributed branch office has to satisfy certain architectural requirements. The design considerations need to meet the Minimum WAN Bandwidth, Maximum RTT, Minimum MTU and fragmentation guidelines captured in guide below: http://www.cisco.com/c/en/us/support/docs/wireless/flex-7500-series-wireless-controllers/112973-flex7500-wbc-guide-00.html#wan

3. Set QoS to prioritize CAPWAP Control Channel traffic on UDP port 5246.

4. Certain features on the WLC require the AP to be in connected mode. Consider the following Feature Limitations in Standalone mode and Local Switching WLANs:

a. Web-authentication: Web Authentication (to an internal or external server) requires the Flex AP to be in connected mode. Web Authentication is not supported if the Flex AP is in Standalone mode. Web Authentication (to an internal or external server) is only supported with Central Authentication. If a WLAN configured for local switching is configured for Local Authentication, you cannot perform Web Authentication.

b. Layer 3 Roaming: FlexConnect deployments only support Layer 2 roaming at the branch. If the size of the branch is large and requires clients to roam between multiple VLANs, it is recommended to use a controller at the branch.

c. TrustSec SXP

5. Define FlexConnect Groups to leverage features, such as CCKM/OKC roaming for Voice, Local EAP, Local Backup Radius Server, and Smart AP Image Upgrade.

a. CCKM/OKC roaming for Voice: FlexConnect Groups are required for CCKM/OKC fast roaming to work with FlexConnect access points. This feature prevents the need to perform a full RADIUS EAP authentication because the client roams from one access point to another, which is vital to voice deployments.

b. Local EAP: FlexConnect groups provide an option to configure Local EAP on APs in a branch site. If the RADIUS/ACS server inside the Data Center is not reachable, then FlexConnect APs automatically acts as a Local-EAP Server to perform Dot1X authentication for wireless branch clients. LEAP, EAP-FAST, EAP-TLS, and LEAP are supported on the FlexConnect AP, although authentication using LEAP is not recommended because it is not secure.

This is how to configure it on the WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup radius ap enable

(Cisco Controller) >config flexconnect group FlexGroup radius ap eap-fast enable

(Cisco Controller) >config flexconnect group FlexGroup radius ap server-key <hidden>

(Cisco Controller) >config flexconnect group FlexGroup radius ap authority id 436973636f0000000000000000000000

(Cisco Controller) >config flexconnect group FlexGroup radius ap authority info Cisco A_ID

(Cisco Controller) >config flexconnect group FlexGroup radius ap user add cisco password <hidden>

c. Local Backup RADIUS Server: You can configure the controller to allow a FlexConnect access point in standalone mode to perform full 802.1X authentication to a backup RADIUS server. In order to increase the resiliency of the branch, administrators can configure a primary backup RADIUS server or both a primary and secondary backup RADIUS server.

This is how to configure it on the WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup radius server auth add primary 9.1.0.100 1812 <hidden>

(Cisco Controller) >config flexconnect group FlexGroup radius server auth add secondary 9.1.0.101 1812 <hidden>

d. Efficient AP Image Upgrade will reduce the downtime for each FlexConnect AP. The basic idea is only one AP of each AP model will download the image from the controller and will act as Master/Server, and the rest of the APs of the same model will work as Slave/Client and will pre-download the AP image from the master.

This is how to configure it on the WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup predownload enable

(Cisco Controller) >config flexconnect group FlexGroup predownload master AP3600

(Cisco Controller) >config flexconnect group FlexGroup predownload ?

 

disable Disable Efficient Upgrade for group

enable Enable Efficient Upgrade for group

master Manual Configuration for master for group

slave Configuration for slave

start Start efficient upgrade only to this flex connect group

 

This is how to view FlexConnect group details on the WLC command line interface:

(Cisco Controller) >show flexconnect group detail FlexGroup

Number of AP's in Group: 2

44:2b:03:a9:78:40

a4:93:4c:3e:fb:5a AP3600 Joined Flexconnect

Efficient AP Image Upgrade ..... Enabled

 

Max Retry Count for Slaves ..... 44

Number Of Masters .............. 1

 

Master-AP-Mac Master-AP-Name Model Manual

a4:93:4c:3e:fb:5a AP3600 c3600I Yes

 

Group Radius Servers Settings:

Type Server Address Port

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

Primary 9.1.0.100 1812

Secondary 9.1.0.101 1812

 

Group Radius AP Settings:

AP RADIUS server............ Enabled

EAP-FAST Auth............... Enabled

LEAP Auth................... Disabled

EAP-TLS Auth................ Enabled

EAP-TLS CERT Download....... Disabled

PEAP Auth................... Enabled

Server Key Auto Generated... No

Server Key.................. <hidden>

Authority ID................ 436973636f0000000000000000000000

Authority Info.............. Cisco A_ID

PAC Timeout................. 0

Multicast on Overridden interface config: Disabled

DHCP Broadcast Overridden interface config: Disabled

Number of User's in Group: 1

cisco

Vlan :........................................... 30

Ingress ACL :................................... None

Egress ACL :.................................... None

Vlan :........................................... 20

Ingress ACL :................................... None

Egress ACL :.................................... None

Group-Specific FlexConnect Wlan-Vlan Mapping:

 

WLAN ID Vlan ID

 

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

 

WLAN ID SSID Central-Dhcp Dns-Override Nat-Pat

6. Enable Local Switching on the WLAN.

a. Connect the FlexConnect AP to a 802.1Q trunk port on the switch and enable VLAN Support

b. When connecting with native VLAN on AP, L2 switch port must also match with corresponding Native VLAN configuration.

This is how to configure it from the WLC command line interface:

(Cisco Controller) >config ap flexconnect vlan ?

enable Enables VLAN on the flexconnect.

disable Disables VLAN on the flexconnect.

native Configure native VLAN

remove Remove the wlan-vlan mapping from AP level

wlan Configure wlan and vlan mapping

add Configure vlan and acl mapping

c. Each corresponding SSID that is allowed to be locally switch should be allowed on the corresponding switch port.

7. Design for Resiliency taking into consideration failures at the WAN, WLC failures, and failures at the RADIUS server.

a. Configure Local Primary and Secondary backup Radius Server at the FlexConnect Group.

This is how to configure it on the WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup radius server auth add primary 9.1.0.100 1812 <hidden>

(Cisco Controller) >config flexconnect group FlexGroup radius server auth add secondary 9.1.0.101 1812 <hidden>

b. For an additional level of resiliency, enable the Local EAP Server on the FlexConnect Group (EAP-FAST, PEAP, EAP-TLS). This feature can be used in conjunction with the FlexConnect backup RADIUS server feature. If a FlexConnect Group is configured with both backup RADIUS server and local authentication, the FlexConnect access point always attempts to authenticate clients by using the primary backup RADIUS server first, followed by the secondary backup RADIUS server (if the primary is not reachable), and finally the Local EAP Server on FlexConnect access point itself (if the primary and secondary are not reachable).

This is how to configure it on the WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup radius ap ?

authority EAP-FAST authority parameters

disable Disables AP based RADIUS Server

eap-cert EAP Root and Device certificate

eap-fast Enables or Disables EAP-FAST authentication

eap-tls Enables or Disables EAP-TLS authentication

enable Enables AP based RADIUS Server

leap Enables or Disables LEAP authentication

pac-timeout EAP-FAST PAC valid period

peap Enables or Disables PEAP authentication

server-key EAP-FAST Server Key parameters

user Manage user list at the AP based Radius Server (max entries 100)

c. Configure a WLC Backup Management Interface Port to provide protection against management port failure.

8. VLAN based central switching is a handy feature for various scenarios where dynamic decisions can be made to local switch or central switch the traffic based on the VLANs returned by the AAA server and the VLANs present at the branch site.

9. When a locally switched WLAN is created with the VLAN support enabled, the default WLAN-VLAN mapping will be that at the WLAN level and will not be a persistent entity across the WLCs unless explicitly configured to be so.

10. With the VLAN tagging feature configured, it is not allowed to configure the native VLAN for the AP. All AP generated packets will be tagged and therefore the AP has to be connected to a trunk switch port.

11. With PPPOE APs, NAT-PAT support is mandatory and cannot be modified.

12. Central DHCP and the Split Tunnel feature use the routing functionality of the AP. Static IP clients are not supported with central-DHCP and local split WLANs.

13. WLAN-VLAN mapping can be configured at the WLAN and FlexConnect Group, as well as at the AP. The AP specific configuration has the highest precedence, followed by FlexConnect Group mapping and then the WLAN level mapping which takes the lowest precedence. If a VLAN is created at the AP by using WLAN-VLAN mapping, the VLAN-ACL should also be created on the AP and not at FlexConnect group.

14. Enable ELM (Enhanced Local Mode for Adaptive wIPS) which provides Adaptive wIPS functionality when serving clients without any impact to client performance.

15. When using the AAA override feature to override the VLAN or ACL, the FlexConnect AP should have the VLAN and ACL pre-created from the WLC for dynamic assignment.

16. The Smart AP Image Upgrade feature is recommended to upgrade branch sites because it conserves WAN bandwidth, reduces upgrade-induced service downtime, and also reduces the risk of download failure over the WAN.

a. Download Image to WLC by using controller CLI/GUI or Prime Infrastructure.

b. Force the boot image to be the Secondary (and not the newly upgraded one) to avoid parallel download of all APs in case of an unexpected WLC reboot.

c. The controller elects a master AP in each FlexConnect Group. The master AP can also be selected manually.

d. Master AP pre-downloads the AP firmware in the secondary boot image. Schedule this per FlexConnect group to limit the WAN exhaust.

e. Once the master AP finishes downloading the image, it sends a message to the controller and the controller instructs the Slave APs to pre-download the AP firmware from the Master AP.

f. Change the boot image of the WLC to point to the new image.

g. Reboot the controller

This is how to configure this feature using WLC command line interface:

(Cisco Controller) >config flexconnect group FlexGroup predownload ?

disable Disable Efficient Upgrade for group

enable Enable Efficient Upgrade for group

master Manual Configuration for master for group

slave Configuration for slave

start Start efficient upgrade only to this flex connect group