• Cisco Class-based QoS discovery and collection plugin
• Introduction
• Installation
• Usage
• Tunable parameters
• Implementation details
• Author

Cisco Class-based QoS discovery and collection plugin

Status: Released; Last modified: 03-MAY-2004

Introduction

DiffServ-based quality of service is being deployed in many networks these days, and the choice of management systems able to monitor QoS parameters is too narrow.

Cisco IOS provides QoS statistics in its CISCO-CLASS-BASED-QOS-MIB. This MIB is far too complex for a regular SNMP collector.

The cbqos RRFW plugin provides a complete solution for automated SNMP discovery and collection for QoS objects on Cisco routers. It is the first open source solution of this kind.

Other existing tools for QoS monitoring are:

• genRtrConfig by Francois Mikus (http://www.acktomic.com).
  
This tool is an add-on to Cricket (http://cricket.sourceforge.net). It provides discovery and statistics for non-hierarchical classmaps counters: pre-policy, post-policy, and drop counters.

Installation

RRFW version 0.1.6 or later is required.

Unpack RRFW distribution and the cbqos plugin in some directory. From RRFW distribution directory, execute

  ./configure --with-plugins=../rrfw-plugin-cbqos-0.1
  make install

See RRFW Installation Instructions for more details on installation options and requirements.

After successful installation, add the following line to your site configuration files rrfw-siteconfig.pl and devdiscover-siteconfig.pl. These files are usually located in /usr/local/rrfw-0.1/share/rrfw:

  require $RRFW::Global::perlConfigDir . '/cbqos-config.pl';

Usage

Use your RRFW the usual way: devdiscover will automatically find QoS objects on your routers, compilexml will find the required templates, and collector will initialize all required tables and will start collecting data.

Note: QoS is a software feature, and there's no means to determine that the configuration has changed. You need to re-run devdiscover and compilexml whenever your QoS configuration changes. As usual, the collector will automatically detect the router reload or RRFW configuration change, and re-initialize its tables.

Tunable parameters

The following parameters may be specified in devdiscover input XML:

• CiscoIOS_cbQoS::red-dscp-values
  
Optional. Comma-separated list of DSCP values to be used for WRED statistics. Symbolic names like AF31 or EF are recognized. When specified, it overrides the default list defined in @RRFW::DevDiscover::CiscoIOS_cbQoS::RedDscpValues in cbqos-config.pl or in devdiscover-siteconfig.pl.
• CiscoIOS_cbQoS::classmaps-only
  
Optional. When set to yes, only classmap statistics are set for collection. Suppressed are statistics for match statements, queueing, RED, shaping, and policying. This significantly reduces the size of datasource tree, amount of SNMP queries, and collector execution time.
• CiscoIOS_cbQoS::suppress-match-statements
  
Optional. When set to yes, disables the match statement statistics. These statistics usually don't bring much of additional information. Besides, in some IOS versions they are almost always not updated (known for: 12.2(15)T7, ...).
• CiscoIOS_cbQoS::suppress-dropnobuf
  
Optional. When set to yes, disables classmap Dropped No Buffer statistics.

Implementation details

CISCO-CLASS-BASED-QOS-MIB uses complex indexing for statistics objects:

cbQosPolicyIndex in cbQosServicePolicyTable is found by matching 6 values: cbQosIfType, cbQosPolicyDirection, cbQosIfIndex, cbQosFrDLCI, cbQosAtmVPI, cbQosAtmVCI
Use cbQosPolicyIndex to access the cbQosObjectsTable, and find the cbQosObjectsIndex and cbQosConfigIndex assigned to the QoS feature.
Use cbQosConfigIndex to access configuration tables (cbQosxxxCfgTable) for information about the feature.
Use cbQosPolicyIndex and cbQosObjectsIndex to access QoS statistics tables (cbQosxxxStatsTable) for information about the QoS feature.

The plugin introduces a special RRFW collector type, ``cisco-cbqos''.

Each RRFW datasource is identified by Service Policy, QoS Feature, and associated SNMP objects type.

The following parameters identify the Service Policy:

 cbqos-direction =>
   "input"
   "output"

 cbqos-interface-name (mapping to IF-MIB interface index)

 cbqos-interface-type =>
   "mainInterface"
   "subInterface"
   "frDLCI" =>
     cbqos-fr-dlci
   "atmPVC" =>
     cbqos-atm-vpi
     cbqos-atm-vci

The following parameters identify the QoS Feature:

 cbqos-object-type =>
   "policymap"
   "classmap" =>
     cbqos-class-map-name
   "matchStatement" =>
     cbqos-match-statement-name
   "queueing" =>
     cbqos-queueing-bandwidth
   "randomDetect"
   "trafficShaping" =>
     cbqos-shaping-rate
   "police" =>
     cbqos-police-rate

SNMP objects are defined in reguar RRFW XML templates. Collector substitutes POL and OBJ strings in snmp-object parameter with the current values of policy and object index correspondingly.

Development of this plugin was sponsored by Cablecom GmbH.

Author

Copyright (c) 2004 Stanislav Sinyagin <ssinyagin@yahoo.com>