How much traffic will Netreo add to my network?

How much traffic Netreo will add to your network depends on a lot of factors, primarily because basic SNMP monitoring is going to have a different load profile than a configuration with a large amount of NetFlow traffic or IP telephony call records. Large numbers of detailed service checks can also have an impact, but after reviewing hundreds of customer configurations, we can provide some general guidelines to give you an idea of what to expect.

SNMP is a very lightweight protocol, so the amount of traffic it contributes is usually a very small amount. A good rule of thumb is that “for every 1,000 devices under management, you can expect an average data rate of approximately 100Kb/sec.” For a remote site with 50 devices being managed, the data rate across that connection would be around 5,000 bits per second. If you aren’t configuring a lot of other management protocols or service checks, this is a fairly accurate estimate you can plan for.

Windows and Linux/Unix hosts will generate slightly more traffic as we collect a large number of per-process statistics from them. In environments that are server-heavy, the actual amount of traffic could be as much as double that estimate, as much as 200Kb/sec per 1,000 devices.

Flow technologies (NetFlow, sFlow, IPFIX) can generate considerably more traffic. In general, flow collection is going to increase your traffic on any given link by somewhere between 0.1% and 1% of the actual traffic in use (depending on the number of connections). So, if you have a fully-loaded T1 circuit (1.5Mbps), adding NetFlow across that circuit is going to increase your traffic somewhere around ~1.5kbps. In aggregate from dozens or hundreds of locations, traffic usage can be considerable. IPFIX or NBAR configurations will use even more—perhaps as much as 2% of the traffic in use in a worst-case scenario. This effect tends to level out above 100Mbps as the number of connections doesn’t increase with the volume of traffic in a linear fashion.