This example illustrates monitoring a mid-size company with two data centers.
Network layout and possible attachment points
Although one NAM Probe could cope with the combined traffic volumes for both data centers, there is no practical way to connect a single NAM Probe's sniffing interfaces to two separate data centers at different geographic locations. One NAM Server reads the measurement data from the two NAM Probes.
Each NAM Probe in this example must see the complete, two-way information exchange between clients and web servers for the particular data center.
Example load and traffic volumes
Each data center serves approximately 4,000 web users (for a total of 8,000 users) who access about 1,000 unique URLs on several web servers; website users load 1 million pages daily. Peak traffic volume at points before or after the firewall can reach 1 Mbps.
Capacity requirements and planning
NAM Probe deployment
Estimate NAM Probe capacity based on the byte rate of bits per second rather than operations per second. In this case, the 1 Mbps load is many times less than the NAM Probe capacity limit for HTTP traffic. So a single NAM Probe is sufficient for each data center, even when each NAM Probe receives data from two attachment points and also produces detailed data for the ADS. For more information, see Planning NAM Probe deployment and configuration
NAM Server deployment
In this web-monitoring example, the expected total of 8,000 users is within the limits that a NAM Server can handle. For more information, see Planning NAM Server deployment.
In capacity terms, a session is a unique URL that is accessed one or more times by a given user on a specific server. Assuming an average of ten sessions per day per user, the 8,000 users will generate approximately 800K sessions in a 10-day interval, which is well within the capacity limits. So you can plan to keep detailed 5-minute data stored for ten days. In addition to that, keep 30 days of one-day roll-ups and 12-months monthly roll-ups.