Obtaining Reliable Bit Rate Measurements in SNMP-Managed Networks

The Simple Network Management Protocol, SNMP, is the most widespread standard for Internet management.  As SNMP stacks are available on most equipment, this protocol has to be considered when it comes to performance management, traffic engineering and network control.  The Simple Network Management Protocol (SNMP) is still the dominant protocol for managing network elements in IP-based networks and the Internet, network managers are acknowledging its limitations with respect to configuration management, application development and decentralization of management tasks.  However, especially when using the predominant version 1, SNMPv1, special care has to be taken to avoid erroneous results when calculating bit rates. In this work, we evaluate six off-the-shelf network components. We demonstrate that bit rate measurements can be completely misleading if the sample intervals that are used are either too large or too small. The devices are evaluated with regards to their updating and response behavior.