A fiery debate arises when discussing flow technologies i.e. NetFlow vs. sFlow. As we all know, existing flow technologies act as a vital and viable solution to troubleshoot network and bandwidth issues. While network engineers contemplate which one is better, NetFlow and sFlow serve as an example of how flow technologies are used in modern network devices.


NetFlow and sFlow – What are they?

NetFlow is a network protocol developed by Cisco Systems for collecting IP traffic information. It’s supported on most platforms and has become the universally accepted standard for traffic monitoring. NetFlow answers the questions of who (users), what (applications), and how network bandwidth is being used.  By understanding NetFlow on a deeper level, you can probe further into the insights and everyday uses that you haven’t thought about.

sFlow is a technology for monitoring network devices that use sampling (to achieve scalability) and is applicable to high speed networks. sFlow performs two types of sampling: random sampling of packets/application layer operations and time-based sampling of counters. These flow samples and counter samples are sent as sFlow datagrams to analyze and report on network traffic i.e. sFlow collector.


NetFlow and sFlow – What are the differences?

Most network devices support either NetFlow or sFlow. Prioritizing what administrator’s want, while managing your network and bandwidth can help during the process of streamlining network traffic and troubleshooting. NetFlow can help you manage IP based traffic information, whereas sFlow can capture non IP traffic by working on Layer 2 and Layer 3 interfaces by sampling most of your network traffic.

For instance, if there’s a sudden increase in network traffic, NetFlow can handle a minimal load by having few flows for massive packet volume. Conversely, sFlow has a 1:N sampling which increases additional work load. However, sFlow may miss some traffic due to the sampling method it employs, while NetFlow gives you an advantage by capturing all network traffic. NetFlow can also be helpful with network forensic analysis and threat detection. sFlow claims to be better because it‘s processed at a core hardware level.

Most available network management tools support both NetFlow and sFlow. If you’re choosing a tool, look for features that support flow technologies, such as NetFlow, sFlow, jFlow or IPFIX.


NetFlow and sFlow – What are their applications?

Both NetFlow and sFlow are used to generate more visibility into an organization’s network. Fundamentally, the usage of NetFlow and sFlow is to eliminate guesswork when it comes to managing network services and making decisions. Typically NetFlow and sFlow are used in:

  • Analyzing network and bandwidth usage by users, applications
  • Measuring WAN traffic and generating statistics for creating network policies
  • Detecting unauthorized network usage - Security and anomaly detection
  • Confirming appropriate bandwidth is allocated using QoS parameters
  • Diagnosing and troubleshooting network problems

With sFlow, packet forwarding information helps analyze the most active routes and specific flows carried by these routes in your network. Understanding these routes and flows creates a possibility for administrators to optimize routing and improve network performance.

It doesn’t matter which type of flow technology you are using. As long as you use a network monitoring tool that supports both, you can focus more on how to manage your resources and optimize your network. Utilizing the best tools available is the key managing loads of traffic data.