LANs typically have high data transfer rates – and this makes it essential to monitor the traffic and bandwidth usage across the LAN links. For instance, server bottlenecks can be identified by studying bandwidth usage – perhaps by tracking seasonal peaks and valleys in the bandwidth pattern. Likewise, malicious network behavior can be tracked by abnormal bandwidth patterns, high traffic flows to particular ports, numerous failed connection etc. All these, and more, can be achieved with LAN bandwidth monitors.
A bandwidth monitor is essentially a software that collects, monitors and analyzes network and application traffic, and offer insights into network utilization – how the network is being used, and by whom. Bandwidth monitoring tools like WhatsUp Gold’s network flow monitor, can function as effective LAN bandwidth monitoring tools by highlighting LAN utilization and identifying traffic based on application/user/device/protocol.
Flow Monitor is, as its name suggests, a flow monitoring technology that uses popular formats like Cisco’s NetFlow, Juniper’s jFlow, sFlow, or IPFIX to measure traffic “flows” in a network. A flow is essentially a series of packets that share common characteristics including source/destination IPs and ports, Type of Service, IP protocol etc. Flow technology is enabled on the network devices (routers, switches), which collect the flow data by sampling packets passing through them. If a packet contains same parameter values as its sampled predecessor, it is incremented as the same flow. The flow data is sent to the flow collector (like the Flow Monitor), which then analyses the data into pertinent information. For instance, the Flow Monitor can show which users, protocols servers are consuming bandwidth, identify congestion problems, monitor unauthorized application usage, and detect security issues like DDoS.
By default, LAN links work on best effort basis – that is all traffic have equal priority. Administrators can ensure business critical applications are guaranteed minimum bandwidth/get traffic priority, by applying QoS (Quality of Service) policies. For LANs, Flow Monitor verifies Differentiated Services Code Point (DSCP) values set for QoS configurations.