switched monitoring (SMON)

Switched Monitoring (SMON) is, in addition to Remote Monitoring(RMON), a method for controlling the data traffic of switches and routers. SMON works with its own implemented bus system independently of the user data bus of the backplane and records measured values and control data of the internetworking components. Thanks to the independent SMON bus, the bandwidth of the backplane available for the user data is not burdened.

SMON is an extension of the RMON protocol and offers, among other things, statistical functions for virtual local area networks( VLAN).

The first version of SMON, which is described as an IETF standard in RFC 2613, operates at Layer 2, which leads to the limitation that multicast and broadcast storms, including those used for search services, cannot be detected. Since the second version of SMON has not yet been standardized, the limitations should be addressed and, among other things, performance should be monitored at the higher layers. SMON-2 can determine quality parameters, such as packet delays, jitter and packet loss, and determine the quality of service( QoS). The SMON values recorded can be made available to the network management and evaluated via the SNMP protocol.

SMON distinguishes between the Device-SMON, the Port-SMON and the VLAN-SMON. The Device-SMON contains information about the utilization, the faulty packets and the 802.1p priority, the Port-SMON about the incoming and outgoing packets, the bandwidth as well as the port utilization and the VLAN-SMON contains the information about the used bandwidth and the packets in the VLAN.