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#Active timer when using netflow archive
#Active timer when using netflow software

Netflow version 9, which is now a IETF standard known as IP Information Export (IPFIX), is the new standard for transporting information from Switches and Routers to a Collector. Netflow is used for finding bandwidth hogs, hunting down network threats, isolating application slowness issues and even for usage based billing by some ISP's. The Netflow Collector can then provide details on things like, the threats detected, the network topology, top interfaces and graph those trends.

#Active timer when using netflow archive

When the flows expire, they're exported off to the Netflow Collector, which will constantly analyze and archive the flows for future reference. So packets that enter the Router that don't have a matching flow entry are first determined to be routeable and if they're accepted, they're then forwarded after a flow cache entry is made.Ī Flow Cache can contain hundreds of thousands of entries, and in some cases, into the Millions of entries. As the following packets that match an existing flow entry come into the router, the byte and packet counters keep increment through each additional data-gram until the connection between the host involved in the flow is torn down. The packet is then routed out the destination interface.

Input Logical Interface (ifIndex) (The interface of the Router or Switch).

ToS Byte – (means Type of Service Byte and takes into account the Precedence, Speed, Throughput Levels and Reliability.

The Flow Cache entry contains information about the Flow including the following: Packets the have the following attributes that are the SAME, are grouped into whats called a FLOW, which are then tallied: Source/Destination IP address, Source/Destination ports, Protocol interface and Class of Service.ĭetermining a Flow is scalable because this data and information is organized into a Database of Netflow information called the Netflow Cache, or Flow Cache. The Attributes 1 of each IP Packet are as follows: When a packet enters an interface that the router/switch hasn't seen before, it will decide whether or not to route the datagram, and if it forwards the datagram it will make an entry in the Flow Cache (in the router or switch) based on matching criteria in the packet.Įach packet within a Switch/Router that is forwarded is examined for a certain set of IP packet attributes that identify the packet and amongst others (you can think of this as a fingerprint of sorts.Īn Ip Flow is made up of a Set of 5 attributes and can have up to 7 total. Netflow Export or Transport Mechanism – This sends data to the Collector to further data reporting and analyzing. NetFlow Cache (sometimes referred to as Data source or Flow Cache) – Stores the IP Flow information. Netflow is made up of a couple components: Related Post: Best Bandwidth Monitoring Tools for Network Traffic Usage Basics of the Protocol

#Active timer when using netflow software

The protocol itself does not analyze the traffic, but as mentioned previous, when configured properly it sends traffic to a Collector or Analyzer, which is either a hardware device or more often than not, a software program.Ĭisco originally developed the protocol for its products and soon after it has been the standard that many other manufacturers are implementing into their products as well, including Juniper (which has “JFlow”), 3Com/HP, Dell and Netgear (SFlow), Ericsson (RFlow), Huawei (NetStream) and Alcatel-Lucent (which uses CFlow). The protocol allows you to really drill down into your network traffic to see where the traffic source is coming from and to where it is destined too when troubleshooting slow LAN or WAN network connections. It allows you to collect traffic and analyze it through a program (Usually called a Netflow Collector or Analyzer) which then organizes the flow records into a format that allows the IT administrator or Network engineer to further analyze the traffic (Source, destination, etc).

The Nexus 1000v has a few predefined flow records in 5.Netflow, a protocol developed by Cisco, is used to collect and record all IP Traffic going to and from a Cisco router or switch that is Netflow enabled. Nexus 1000v Netflow Configuration for 5.x: I'm going to go over Netflow configuration and some useful commands to troubleshoot issues with NetFlow.