WLC HA Status Test
The new High Availability (HA) feature (that is, AP SSO) set within the Cisco WLC 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 new architecture for HA is for box-to-box redundancy. In other words, 1:1 where one WLC will be in an Active state and the second WLC will be in a Hot Standby state continuously monitoring the health of the Active WLC via a Redundant Port. Both the WLCs will share the same set of configurations including the IP address of the Management interface. The WLC in the Standby state does not need to be configured independently as the entire configuration (Bulk Configuration while boot up and Incremental Configuration in runtime) will be synced from the Active WLC to the Standby WLC via a Redundant Port. The AP's CAPWAP State (only APs which are in a run state) is also synced, and a mirror copy of the AP database is maintained on 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's Active WLC. There is no preempt functionality. When the previous Active WLC comes back, it will not take the role of the Active WLC, but will negotiate its state with the current Active WLC and transition to a Standby state.
The overall goal for the addition of AP SSO support to the Cisco Unified Wireless LAN is to reduce major downtime in wireless networks due to failure conditions that may occur due to box failover or network failover. Hence, at any give point in time, an administrator should know whether/not the HA is configured and also the HA state of the WLC. The WLC HA Status Test helps to determine this.
This test continuously monitors the target WLC and reports whether or not the HA is configured in the WLC and the HA state of the WLC. This test also reports whether or not switch over occurred in the controller.
Target of the test : Cisco WLAN Controller
Agent deploying the test : An external agent
Outputs of the test : One set of results for the target Cisco WLAN Controller being monitored.
| Parameter | Description |
|---|---|
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Test period |
How often should the test be executed. |
|
Host |
The IP address of the host for which this test is to be configured. |
|
SNMPPort |
The port at which the monitored target exposes its SNMP MIB; the default is 161. |
|
SNMPVersion |
By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list. |
|
SNMPCommunity |
The SNMP community name that the test uses to communicate with the firewall. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear. |
|
Username |
This parameter appears only when v3 is selected as the SNMPversion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. |
|
Context |
This parameter appears only when v3 is selected as the SNMPVERSION. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box. By default, this parameter is set to none. |
|
AuthPass |
Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3. |
|
Confirm Password |
Confirm the AuthPass by retyping it here. |
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AuthType |
This parameter too appears only if v3 is selected as the SNMPversion. From the AuthType list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:
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EncryptFlag |
This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. |
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EncryptType |
If the EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:
|
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EncryptPassword |
Specify the encryption password here. |
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Confirm Password |
Confirm the encryption password by retyping it here. |
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Timeout |
Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds. |
|
Data Over TCP |
By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No. |
|
EngineID |
This parameter appears only when v3 is selected as the SNMPVersion. Sometimes, the test may not report metrics when AES192 or AES256 is chosen as the Encryption type. To ensure that the test report metrics consistently, administrators need to set this flag to Yes. By default, this parameter is set to No. |
| Measurement | Description | Measurement Unit | Interpretation | ||||||
|---|---|---|---|---|---|---|---|---|---|
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Is HA configured? |
Indicates whether or not HA is configured in the target controller. |
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The values that this measure can take and their corresponding numeric values are as follows:
Note: By default, this measure reports the Measure Values listed in the table above to indicate the whether/not HA is confiured. In the graph of this measure however, the same is represented using the corresponding numeric equivalents only. |
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HA state |
Indicates the current HA state of the target WLC. |
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The values that this measure can take and their corresponding numeric values are as follows:
Note: By default, this measure reports the Measure Values listed in the table above to indicate the current HA state of the controller. In the graph of this measure however, the same is represented using the corresponding numeric equivalents only. |
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Switchover occurred? |
Indicates whether or not switch over occurred. |
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The values that this measure can take and their corresponding numeric values are as follows:
Note: By default, this measure reports the Measure Values listed in the table above to indicate the whether/not switch over occurred.In the graph of this measure however, the same is represented using the corresponding numeric equivalents only. |
