3/19/2023 0 Comments Iograph multiple monitorsThe minimum interval can be set to five seconds and even one second on some third-party NMSs. Second-level monitoring interval: Generally, an NMS monitors traffic at an interval of 30s. Limited management scale: The pull mode is used to obtain monitoring data of devices, and cannot monitor a large number of network nodes. The NMS obtains device data in SNMP get mode, which has the following disadvantages: The traffic curves seem to be smooth on the NMS although microbursts (packet loss) have occurred. The NMS monitors port traffic around the clock and determines the traffic trend on the network based on traffic curves of devices. Therefore, more buffer space is consumed and more packets are discarded due to congestion when microbursts occur. On an actual network, the number of ingress ports is greater than that of egress ports. Without considering overhead data such as the inter-frame gap, preamble, frame checksum, and packet header, the microburst duration is 4 ms (5 MB/10 Gbps). Therefore, 4 MB data is discarded due to insufficient buffer space. However, the switch has only 1 MB buffer space. It sends only 5 MB data out and buffers the other 5 MB data for transmission later. Port3 supports only a rate of 10 Gbps, which is a half of the total transmission rate. Assume that Port1 and Port2 respectively send 5 MB data to Port3 at a line rate of 10 Gbps. ![]() The following figure shows a typical millisecond-level microburst scenario. If the switch does not have sufficient buffer space, the excess data is discarded, causing congestion and packet loss. When a microburst exceeds the forwarding capability of a switch, the switch buffers the burst data for transmission later.
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