Other Network Management Technologies – IP Multicast and Network Management

This section covers technologies used to gather network information, such as RMON, NetFlow, CDP, LLDP, and syslog.

RMON

Remote Monitoring (RMON) is a standard monitoring specification that enables network monitoring devices and console systems to exchange network monitoring data. RMON provides more information than SNMP, but it also requires more sophisticated data collection devices (network probes). RMON looks at MAC-layer data and provides aggregate information on the statistics and LAN traffic.

Enterprise networks deploy network probes on several network segments; these probes report back to the RMON console. RMON allows network statistics to be collected even if a failure occurs between a probe and the RMON console. RMON1 is defined in RFCs 1757 and 2819, and additions for RMON2 are defined in RFC 2021.

The RMON MIB is located at iso.org.dod.internet.mgt.mib.rmon or the equivalent object descriptor 1.3.6.1.2.1.16. RMON1 defines nine monitoring groups, each of which provides specific sets of data. An additional group beyond these nine is defined for Token Ring. Each group is optional, so vendors do not need to support all the groups in the MIB. Table 5-8 shows the RMON1 groups.

Table 5-8 RMON1 Groups

RMON2

RMON1 is focused on the data link and physical layers of the OSI model. As shown in Figure 5-6, RMON2 provides an extension for monitoring upper-layer protocols.

Figure 5-6 RMON1 and RMON2 Compared to the OSI Model

RMON2, defined in RFC 2021, extends the RMON group with the MIB groups listed in Table 5-9.

Table 5-9 RMON2 Groups