QoS Statistics Overview

Statistics profiles enable you to gather statistics for the rate at which packets are forwarded out of a queue and for the rate at which committed, conformed, or exceeded packets are dropped. Statistics profiles also enable you to use events to monitor the rate statistics. You can then use show commands to view the results of the statistics gathering.

You can create up to 250 statistics profiles on the E Series Broadband Services Routers. The profiles are referenced by a queue rule within a QoS profile.

Statistics cannot be collected on failover queues.

When you create a statistics profile, you specify the time period over which statistics are gathered. To gather event statistics, you configure the thresholds for triggering rate-event reporting.

Rate Statistics

You can configure the E Series router to gather statistics for the rate at which queues forward and drop packets.

Queue rate statistics measure the forwarding and drop rates of each queue in bits per second. All bytes in the Layer 2 encapsulation are included in the rate calculation. For example, rates for a queue on Ethernet include the Ethernet and VLAN encapsulations.

For ATM modules, you can optionally configure queue statistics and queue rates to include the cell encapsulation and padding. Cell encapsulation and padding are referred to as the cell tax. The QoS shaping mode that you set on ATM line modules determines whether queue rate statistics include cell tax.

Event Statistics

You can configure the E Series router to count the number of times that forwarding or drop rates exceed a specific threshold. Events can be useful when you are monitoring service level agreements. For example, you might count the number of times that the drop rate of a queue is nonzero.

Bulk Statistics Support for QoS Statistics

You can obtain queue-level QoS statistics for each logical interface by querying the SNMP MIB. However, using SNMP to obtain queue-level statistics consumes significant network bandwidth because SNMP polls large volumes of data frequently. As an alternative to using the SNMP MIB, you can use the bulkstats statistics application.

The bulk statistics application provides components to configure and organize network accounting data in a flexible manner. The application reduces the consumption of network bandwidth by collecting queue-level statistics and periodically transferring the data to a remote server. You can configure the bulk statistics schemas to export network accounting data. In particular, the QoS schema supports the export of queue-level QoS statistics on egress queues for various interface types.

Configuring QoS schemas helps service providers monitor their network and report congestion and oversubscription by obtaining queue-level statistics and configuration information for each logical interface.

For information about schemas and configuring a bulk statistics schema to export queue-level QoS statistics for egress queues on the router, see JunosE System Basics Configuration Guide, Chapter 4, Configuring SNMP.

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