Applications in today's enterprise networks require different levels of service based upon business requirements. The network can provide a variety of services to help ensure that your mission-critical applications receive the bandwidth they need to deliver the desired performance levels. The difficulty is that today's Internet-based and client-server applications make it difficult for the network to identify and provide the proper level of control you need. NBAR solves this problem by adding intelligent network classification to your infrastructure.

NBAR, an important component of the Cisco Content Networking architecture, is a new classification engine in Cisco IOS? Software that can recognize a wide variety of applications, including Web-based applications and client/server applications that dynamically assign TCP or User Datagram Protocol (UDP) port numbers. After the application is recognized, the network can invoke specific services for that particular application. NBAR currently works with quality-of-service (QoS) features to help ensure that the network bandwidth is best used to fulfill your business objectives.

When run on an NBAR-supported Cisco router, this test periodically polls the NBAR MIB to auto-discover the interfaces for which NBAR is enabled, and reports the following for each discovered interface:

• The network protocols handled by that interface;
• The traffic generated for every protocol;
• The bandwidth utilized per protocol.

This way, the test not only reveals busy, bandwidth-intensive interfaces, but also turns the spotlight on specific protocols on those interfaces that are causing excessive bandwidth consumption. Moreover, with the help of these protocol-level usage metrics, administrators can assess how various interfaces and protocols use the network resources, and accordingly fine-tune network policies.

The first step to running this test is to enable NBAR on each interface for which you want to collect NBAR statistics. To know how how to enable NBAR on each interface, refer to the Monitoring Cisco Routers chapter of the Monitoring Network Elements document.

To know how how to enable NBAR on each interface, refer to Section 2.2.4 of Monitoring Network Elements document.

This page depicts the default parameters that need to be configured for the NBarTest.

• The TEST PERIOD list box helps the user to decide how often this test needs to be executed. 

• Specify the port number through which the device exposes its SNMP MIB in the SNMPPORT text box. The default value is 161.

• 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.

• Provide the SNMP community name that the test uses to communicate with the device in the SNMPCOMMUNITY text box. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVERSION chosen is v3, then this parameter will not appear.

• The USERNAME 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 the USERNAME parameter.

• The CONTEXT 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.

• Specify the password that corresponds to the above-mentioned USERNAME in the AUTHPASS text box. This parameter once again appears only if the SNMPVERSION selected is v3.

• Confirm the AUTHPASS by retyping it in the CONFIRM PASSWORD text box.

• The AUTHTYPE 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:

  • MD5 - Message Digest Algorithm
  • SHA - Secure Hash Algorithm

• The ENCRYPTFLAG flag appears only when v3 is selected as the SNMPVERSION. By default, the eG agent does not encrypt SNMP requests. Accordingly, the ENCRYPTFLAG is set to NO by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the YES option.

• 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:

  • DES - Data Encryption Standard
  • AES - Advanced Encryption Standard

• Specify the encryption password in the ENCRYPTPASSWORD text box.

• Confirm the encryption password by retyping it in the CONFIRM PASSWORD text box.

• Specify the maximum duration (in seconds) for which the test will wait for a response from the router in the TIMEOUT text box.

• By default, the ACTIVE PROTOCOLS ONLY flag is set to No, indicating that, by default, this test reports metrics for all protocols handled by an interface. To ensure that the test monitors only those protocols that are currently active, set this flag to Yes.

• Specify a comma-separated list of interfaces to be excluded from monitoring in the IGNORE INTERFACES text box. By default, the test monitors all interfaces for which NBAR is enabled. Accordingly, this parameter is set to none by default.

• By default, the test monitors all protocols handled by an interface. This is why, the SHOW PROTOCOLS parameter is set to all by default. To make sure that the test monitors only specific protocols per interface, provide a comma-separated list of protocols here.

• By default, the value 1 is displayed in the MIN BANDWIDTH PERCENT text box. This indicates that, by default, the test will consider only those protocols that are using 1% or more of current traffic. You can increase or decrease this value based on your monitoring needs. If you set this value to 0, then all protocols will be monitored.

• 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 the DATA OVER TCP flag to Yes. By default, this flag is set to No.

• Once the necessary values have been provided, clicking on the Update button will register the changes made.

When changing default configurations of tests, the values with "$" indicate variables that will be replaced by the eG system according to the specific server being managed - for instance, $hostName is the host/nickname of the target host, $port is the port number of the server being monitored. E.g., for a server xyz:80, $hostName will be changed automatically by the eG manager to "xyz" and $port will be changed to "80" when configuring a test.