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Foglight Experience Monitor 5.8.1 - Installation and Administration Guide

Installing and configuring Multi-appliance clusters Configuring the appliance Specifying monitored web traffic Transforming monitored URLs Managing applications Foglight components and the appliance Using the console program Troubleshooting the appliance Appendix: Third party software Appendix: Dell PowerEdge system appliance

Installing and configuring

Foglight® Experience Monitor is a comprehensive appliance-based solution that empowers organizations to effectively manage, troubleshoot, and optimize all components of the service delivery chain under their control. With our turn-key, self-contained computer system, customers gain unprecedented visibility into the inner workings of their network infrastructure and the quality of the end user’s experience. The appliance provides concise, accurate information in real-time about component performance, systematic failures, and a wealth of other information.

This Installation and Administration Guide provides configuration instructions, conceptual information, and instructions on how to use the browser interface. This guide is intended for users who want to configure Foglight Experience Monitor using the browser interface.

Foglight Experience Monitor appliances are shipped with the Foglight Experience Monitor Quick Installation Guide, which provides all the essential information required to physically install the appliance, connect it to your network, and configure it to collect network traffic.

This section follows the steps outlined in the Quick Installation Guide, and provides additional information about installing and configuring the appliance, as well as references to topics covered elsewhere in the Installation and Administration Guide or in the User Guide.

For more information, see these topics:

Pre-installation considerations

This section provides a quick overview of items and network information required during the installation of a Foglight Experience Monitor appliance.

For more information, see these topics:

Required hardware and network information

The following hardware is required before installation:

Monitor and Keyboard—during the installation process, you need a VGA monitor and keyboard with a USB connector to perform the initial setup of the appliance.
Network Cables—the appliance requires network cables to connect its Control port to your network and its Monitoring ports to network taps. If you plan to use multiple Monitoring ports, the corresponding number of cables is required (for more information, see Multiple monitoring ports).

The following network information is required before installation:

Appliance IP Address—a unique IP address assigned to Foglight Experience Monitor.
Subnet Mask—the subnet mask that corresponds to the Foglight Experience Monitor IP address and the subnet.
Gateway—the IP address of your network’s gateway.
Primary DNS IP Address—allows the appliance to perform DNS look-ups.
Network Time Protocol (NTP) server—the IP address of one or more NTP servers. This allows the appliance to synchronize its clock with an external NTP server.
Ports—the port numbers used on your network for HTTP and HTTPS network traffic.

The Monitor Devices menu in the console program shows which monitoring ports are in use. For more information about the console program, see Displaying information for monitor devices and Accessing the console program.

Network taps

A network tap provides monitoring access to the traffic flowing across a network. Different types of devices are often used as network taps, but only full-duplex network taps and smart taps with full-duplex enabled guarantee the 100% data capture that requires to provide complete and accurate data processing and reporting. A true full-duplex tap splits the ingress traffic (requests to the web servers) and egress traffic (responses from the web servers) into two streams. When those streams are fed into two separate monitoring NICs on an appliance, you get full data capture.

Installing a tap between two points on a network requires that the network cable connecting these points be replaced with a pair of cables both feeding into the tap. The tap passes through all traffic between the two points normally so there is no disruption to the normal traffic flow, and it also copies that traffic to its monitor port. Connecting the tap’s monitor port to one of the appliance’s monitoring ports provides the network traffic that the appliance needs to monitor your applications. Two tap providers include Datacom Systems ( and NetOptics (

It is important that you consider the type of ports you are connecting (for example, RJ45, fiber LC, fiber SC). Network taps have different connector options that should match the type of connections used on your network.

To connect the network tap to a network, disconnect the cables from switch/server/router A and B. Next, connect the cable from switch/server/router A into Network port A on the network tap, and the cable from switch/server/router B into Network port B on the network tap.

To connect the network tap to the appliance, connect Monitor port A to Monitoring NIC 1 (eth2) on the Foglight Experience Monitor appliance. Next, connect Monitor port B to Monitoring NIC 2 (eth3) on the Foglight Experience Monitor appliance.

Foglight Experience Monitor currently supports Dell PowerEdge systems that have up to eight monitoring NIC ports.

NOTE: The number of Ethernet ports available on your appliance varies, depending on the hardware type. For a list of supported hardware platforms and guidance in identifying the Ethernet ports, see Appendix: Dell PowerEdge system appliance.

When using multiple monitoring ports, the appliance automatically reads each NIC port for incoming traffic. No additional configuration on the part of the administrator is required. The console program allows you to see which ports the appliance is using for monitoring and enables you to perform basic troubleshooting for each port.

SPAN ports and aggregation network taps are often used for small-scale monitoring purposes. However, they are not reliable enough to support a large-scale, enterprise-critical monitoring solution like . The following bullets explain why these devices are unsuitable for use with .

SPAN ports — SPAN ports (also known as diagnostic ports) can be found on most switches and routers. Network traffic flowing through a switch can be mirrored to the SPAN port, which in turn connects to a monitoring solution. Switch providers do not guarantee that 100% of the traffic reaches the SPAN port. Spikes in traffic through the switch can result in a significant number of dropped packets (from 5% to as much as 20% of all packets). Dropped packets translate to poor data quality in .
Aggregation network taps — Aggregation network taps take a full-duplex link and merge the ingress and egress streams into a one half-duplex stream. While they drop substantially fewer packets than SPAN ports (due to the use of buffering), aggregation taps are not guaranteed to capture 100% of the traffic routed through them. Aggregation taps generally drop less than 1% of packets, but a 1% drop rate (potentially higher in some instances) has a significant impact on the quality of the data in .

For information on supported network taps, see Network taps.

In the simplest case, where the traffic you want to monitor is handled by one or two web servers, connect the appliance to a network tap located in front of the individual web servers. The appliance monitors only this traffic.

To monitor all web servers in a server farm, connect the appliance to a network tap between the firewall and the load balancer, as shown in the following diagram. This allows an appliance to see all traffic before it is separated out by server destinations. Redundant paths to the server farm (or multiple server farms) may mean deploying additional network taps to obtain complete coverage.

When the network tap is installed between the firewall and the load balancer, the traffic contains only the IP address of the load balancer rather than the web servers. While this behavior is important for security purposes, it means that Foglight Experience Monitor attributes the data for all web servers to the load balancer IP address. Usually, you want data attributed to individual web servers.

To enable the appliance to track data by web server, you need to configure the web servers to insert an extra shared HTTP response header into the traffic. For example, you can create an HTTP response header called SERVER-ID. On each web server, you assign a unique, fictitious (for security purposes) IP address to this header.

After the Foglight Experience Monitor web console is running, an FxM Administrator defines a server identifier with the same name as the response header, and the appliance automatically begins tracking hits by web server. For more information, see Configuring server options.

Some load balancers and all reverse proxies multiplex requests from multiple client connections onto one proxy network connection to the web server. So, while there could be thousands of connections coming into the website, the load balancer or proxy may maintain only a dozen connections to each web server.

This network architecture will affect some of the metrics collected by Foglight Experience Monitor, depending on where the network tap is installed in relation to the load balancer or proxy. The affected metrics are Network Latency and Processing Time for hits and pages, which are also included in the calculations of End-to-End Time for hits and pages. For more information about how these metrics are calculated, see “How standard metrics are calculated” in the FxM Metric Reference Guide.

When a network tap is installed between the client and the reverse proxy, Network Latency is an estimate of the time it takes for a request to travel from the end user’s device to the point where the tap is located. This is the desired measurement. The Processing Time includes the time spent on the request by the load balancer or reverse proxy and the web server, which in many cases is acceptable, but may not be desirable if your stakeholders want the Processing Time to reflect the performance of the web server only.

When a tap is between the load balancer or reverse proxy and the server farm, the Processing Time reflects the time spent by a web server without the overhead of the load balancer or proxy, but the Network Latency is a fraction of the actual Network Latency. In this scenario, Network Latency is based on the time it takes for a request to travel from the load balancer or reverse proxy to the tap.

The following table summarizes the trade-off in metric calculations. Select the deployment option that suits your needs.

Estimate of time elapsed from the end user’s device to the tap, which is the expected value.

Time spent on a request by the load balancer or reverse proxy and a web server.

Estimate of time elapsed from the load balancer or reverse proxy to the tap, which is a fraction of the expected value.

Time spent on a request by a web server.

Some customers install network taps in both locations and configure two separate installations of Foglight Experience Monitor to monitor the taps. The Foglight Experience Monitor instance monitoring the client side tap provides accurate Network Latency metrics, while the Foglight Experience Monitor instance monitoring the server farm side provides accurate Processing Times and volume metrics for each web server.

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