ccna 200 301 study guide

ccna 200 301 study guide.Tip: Although NetFlow is very easy to implement and transparent to the network, it also consumes additional memory on Cisco routers. This is because NetFlow stores information in the "cache" of the device. The default size of this cache varies by platform, and administrators can adjust this value.Network FlowThe key to NetFlow, as its name suggests, is that it uses the concept of flows to split TCP/IP traffic and use it for statistical logging. So what is a flow in a NetFlow application? It is a continuous sequence of unidirectional packets from a specific source system to a specific destination system. NetFlow is obviously built on TCP/IP, with the source and destination defined by its network layer IP address, the transport layer source, and the destination port number.NetFlow's technology has evolved over several generations to provide more and more precision in defining flows, but "classic" NetFlow uses a combination of seven key fields to segment flows. If the value of any one of these fields differs from the rest of the packet, it is an unmistakable indication that it is a different flow.Source IP address.Destination IP address. . Source port number. . Destination port number.... Layer 3 Protocol Type.Type of Service (ToS) tag. . Input Logic Interface. The first four fields used to identify the flow are similar. Source and Destination IP Address. source and destination ports identify the connection between the source and destination applications.The Layer 3 protocol type identifies the Layer 3 protocol header file that follows the IP header file. In addition. the ToS bytes in the IPv4 header file carry some information related to how the device should apply quality of service (QoS) rules to the packets of the flow.Configuring NetFlow Configuring NetFlow on a router requires two separate configuration tasks.(1) use the