This document describes how to set-up and use the Network Performance Monitor solution in Log Analytics, which helps you monitor the performance of your networks-in near real-time-to detect and locate network performance bottlenecks. With the Network Performance Monitor solution, you can monitor the loss and latency between two networks, subnets or servers. Network Performance Monitor detects network issues like traffic blackholing, routing errors, and issues that conventional network monitoring methods are not able to detect. Network Performance Monitor generates alerts and notifies as and when a threshold is breached for a network link. These thresholds can be learned automatically by the system or you can configure them to use custom alert rules. Network Performance Monitor ensures timely detection of network performance issues and localizes the source of the problem to a particular network segment or device.
You can detect network issues with the solution dashboard which displays summarized information about your network including recent network health events, unhealthy network links, and subnetwork links that are facing high packet loss and latency. You can drill-down into a network link to view the current health status of subnetwork links as well as node-to-node links. You can also view the historical trend of loss and latency at the network, subnetwork, and node-to-node level. You can detect transient network issues by viewing historical trend charts for packet loss and latency and locate network bottlenecks on a topology map. The interactive topology graph allows you to visualize the hop-by-hop network routes and determine the source of the problem. Like any other solutions, you can use Log Search for various analytics requirements to create custom reports based on the data collected by Network Performance Monitor.
The solution uses synthetic transactions as a primary mechanism to detect network faults. So, you can use it without regard for a specific network device's vendor or model. It works across on-premises, cloud (IaaS), and hybrid environments. The solution automatically discovers the network topology and various routes in your network.
Typical network monitoring products focus on monitoring the network device (routers, switches etc.) health but do not provide insights into the actual quality of network connectivity between two points, which Network Performance Monitor does.
Using the solution standalone
If you want to monitor the quality of network connections between their critical workloads, networks, datacenters or office sites, then you can use the Network Performance Monitor solution by itself to monitor connectivity health between:
- multiple datacenters or office sites that are connected using a public or private network
- critical workloads that are running line of business applications
- public cloud services like Microsoft Azure or Amazon Web Services (AWS) and on-premises networks, if you have IaaS (VM) available and you have gateways configured to allow communication between on-premises networks and cloud networks
- Azure and on-premises networks when you use Express Route
Using the solution with other networking tools
If you want to monitor a line of business application, you can use the Network Performance Monitor solution as a companion solution to other network tools. A slow network can lead to slow applications and Network Performance Monitor can help you investigate application performance issues that are caused by underlying networking issues. Because the solution does not require any access to network devices, the application administrator doesn't need to rely on a networking team to provide information about how the network is affecting applications.
Also, if you already invest in other network monitoring tools, then the solution can complement those tools because most traditional network monitoring solutions do not provide insights into end-to-end network performance metrics like loss and latency. The Network Performance Monitor solution can help fill that gap.
Installing and configuring agents for the solution
You'll need to install at least 2 agents in order to have enough data to discover and monitor your network resources. Otherwise, the solution will remain in a configuring state until you install and configure additional agents.
Where to install the agents
Before you install agents, consider the topology of your network and what parts of the network you want to monitor. We recommend that you install more than one agent for each subnet that you want to monitor. In other words, for every subnet that you want to monitor, choose two or more servers or VMs and install the agent on them.
If you are unsure about the topology of your network, install the agents on servers with critical workloads where you want to monitor the network performance. For example, you might want to keep track of a network connection between a Web server and a server running SQL Server. In this example, you'd install an agent on both servers.
Agents monitor network connectivity (links) between hosts -- not the hosts themselves. So, to monitor a network link, you must install agents on both endpoints of that link.
If you intend to use the ICMP protocol for synthetic transactions, you need to enable the following firewall rules for reliably utilizing ICMP:
netsh advfirewall firewall add rule name="NPMDICMPV4Echo" protocol="icmpv4:8,any" dir=in action=allow netsh advfirewall firewall add rule name="NPMDICMPV6Echo" protocol="icmpv6:128,any" dir=in action=allow netsh advfirewall firewall add rule name="NPMDICMPV4DestinationUnreachable" protocol="icmpv4:3,any" dir=in action=allow netsh advfirewall firewall add rule name="NPMDICMPV6DestinationUnreachable" protocol="icmpv6:1,any" dir=in action=allow netsh advfirewall firewall add rule name="NPMDICMPV4TimeExceeded" protocol="icmpv4:11,any" dir=in action=allow netsh advfirewall firewall add rule name="NPMDICMPV6TimeExceeded" protocol="icmpv6:3,any" dir=in action=allow
If you intend to use the TCP protocol you need to open firewall ports for those computers to ensure that agents can communicate. You need to download and then run the EnableRules.ps1 PowerShell script without any parameters in a PowerShell window with administrative privileges.
The script creates registry keys required by the Network Performance Monitor and it creates Windows firewall rules to allow agents to create TCP connections with each other. The registry keys created by the script also specify whether to log the debug logs and the path for the logs file. It also defines the agent TCP port used for communication. The values for these keys are automatically set by the script, so you should not manually change these keys.
The port opened by default is 8084. You can use a custom port by providing the parameter
portNumber to the script. However, the same port should be used on all the computers where the script is run.
The EnableRules.ps1 script configures Windows firewall rules only on the computer where the script is run. If you have a network firewall, you should make sure that it allows traffic destined for the TCP port being used by Network Performance Monitor.
Configuring the solution
Use the following information to install and configure the solution.
The Network Performance Monitor solution acquires data from computers running Windows Server 2008 SP 1 or later or Windows 7 SP1 or later, which are the same requirements as the Microsoft Monitoring Agent (MMA). NPM agents can also run on Windows desktop/client operating systems (Windows 10, Windows 8.1, Windows 8 and Windows 7).
The agents for Windows server operating systems support both TCP and ICMP as the protocols for synthetic transaction. However, the agents for Windows client operating systems only support ICMP as the protocol for synthetic transaction.
Add the Network Performance Monitor solution to your workspace from Azure marketplace or by using the process described in Add Log Analytics solutions from the Solutions Gallery.
- In the OMS portal, you'll see a new tile titled Network Performance Monitor with the message Solution requires additional configuration. You'll need to configure the solution to add networks based on subnetworks and nodes that are discovered by agents. Click Network Performance Monitor to start configuring the default network.
Configure the solution with a default network
On the configuration page, you'll see a single network named Default. When you haven't defined any networks, all the automatically-discovered subnets are placed in the Default network.
Whenever you create a network, you add a subnet to it and that subnet is removed from the Default network. If you delete a network, all its subnets are automatically returned to the Default network.
In other words, the Default network is the container for all the subnets that are not contained in any user-defined network. You cannot edit or delete the Default network. It always remains in the system. However, you can create as many networks as you need.
In most cases, the subnets in your organization will be arranged in more than one network and you should create one or more networks to logically group your subnets.
Create new networks
A network in Network Performance Monitor is a container for subnets. You can create a network with any name that you want and add subnets to the network. For example, you can create a network named Building1 and then add subnets, or you can create a network named DMZ and then add all subnets belonging to demilitarized zone to this network.
To create a new network
- Click Add network and then type the network name and description.
- Select one or more subnets, and then click Add.
- Click Save to save the configuration.
Wait for data aggregation
After you've saved the configuration for first time, the solution starts collecting network packet loss and latency information between the nodes where agents are installed. This process can take a while, sometimes over 30 minutes. During this state, the Network Performance Monitor tile in the overview page displays a message stating Data aggregation in process.
When the data has been uploaded, you'll see the Network Performance Monitor tile updated showing data.
Click the tile to view the Network Performance Monitor dashboard.
Edit monitoring settings for subnets
All subnets where at least one agent was installed are listed on the Subnetworks tab in the configuration page.
To enable or disable monitoring for particular subnetworks
- Select or clear the box next to the subnetwork ID and then ensure that Use for Monitoring is selected or cleared, as appropriate. You can select or clear multiple subnets. When disabled, subnetworks are not monitored as the agents will be updated to stop pinging other agents.
- Choose the nodes that you want to monitor for a particular subnetwork by selecting the subnetwork from the list and moving the required nodes between the lists containing unmonitored and monitored nodes. You can add a custom description to the subnetwork, if you like.
- Click Save to save the configuration.
Choose nodes to monitor
All the nodes that have an agent installed on them are listed in the Nodes tab.
To enable or disable monitoring for nodes
- Select or clear the nodes that you want to monitor or stop monitoring.
- Click Use for Monitoring, or clear it, as appropriate.
- Click Save.
Set monitoring rules
Network Performance Monitor generates health events about the connectivity between a pair of nodes or subnetwork or network links when a threshold is breached. These thresholds can be learned automatically by the system or you can configure them custom alert rules.
The Default rule is created by the system and it creates a health event whenever loss or latency between any pair of networks or subnetwork links breaches the system-learned threshold. You can choose to disable the default rule and create custom monitoring rules
To create custom monitoring rules
- Click Add Rule in the Monitor tab and enter the rule name and description.
- Select the pair of network or subnetwork links to monitor from the lists.
- First select the network in which the first subnetwork/s of interest is contained from the network dropdown, and then select the subnetwork/s from the corresponding subnetwork dropdown. Select All subnetworks if you want to monitor all the subnetworks in a network link. Similarly select the other subnetwork/s of interest. And, you can click Add Exception to exclude monitoring for particular subnetwork links from the selection you've made.
- Choose between ICMP and TCP protocols for executing synthetic transactions.
- If you don't want to create health events for the items you've selected, then clear Enable health monitoring on the links covered by this rule.
- Choose monitoring conditions. You can set custom thresholds for health event generation by typing threshold values. Whenever the value of the condition goes above its selected threshold for the selected network/subnetwork pair, a health event is generated.
- Click Save to save the configuration.
After you save a monitoring rule, you can integrate that rule with Alert Management by clicking Create Alert. An alert rule is automatically created with the search query and other required parameters automatically filled-in. Using an alert rule, you can receive email-based alerts, in addition to the existing alerts within NPM. Alerts can also trigger remedial actions with runbooks or they can integrate with existing service management solutions using webhooks. You can click Manage Alert to edit the alert settings.
Choose the right protocol-ICMP or TCP
Network Performance Monitor (NPM) uses synthetic transactions to calculate network performance metrics like packet loss and link latency. To understand this better, consider an NPM agent connected to one end of a network link. This NPM agent sends probe packets to a second NPM agent connected to another end of the network. The second agent replies with response packets. This process is repeated a few times. By measuring the number of replies and time taken to receive each reply, the first NPM agent assesses link latency and packet drops.
The format, size and sequence of these packets is determined by the protocol that you choose when you create monitoring rules. Based on protocol of the packets, the intermediate network devices (routers, switches etc.) might process these packets differently. Consequently, your protocol choice affects the accuracy of the results. And, your protocol choice also determines whether you must take any manual steps after you deploy the NPM solution.
NPM offers you the choice between ICMP and TCP protocols for executing synthetic transactions. If you choose ICMP when you create a synthetic transaction rule, the NPM agents use ICMP ECHO messages to calculate the network latency and packet loss. ICMP ECHO uses the same message that is sent by the conventional Ping utility. When you use TCP as the protocol, NPM agents send TCP SYN packet over the network. This is followed by a TCP handshake completion and then removing the connection using RST packets.
Points to consider before choosing the protocol
Consider the following information before you choose a protocol to use:
Discovering multiple network routes
TCP provides more accurate when discovering multiple routes and it needs with fewer agents in each subnet. For example, one or two agents using TCP can discover all redundant paths between subnets. However, you need several agents using ICMP to achieve similar results. Using ICMP, if you have N number of routes between two subnets you need more than 5N agents in either a source or destination subnet.
Accuracy of results
Routers and switches tend to assign lower priority to ICMP ECHO packets compared to TCP packets. In certain situations, when network devices are heavily loaded, the data obtained by TCP more closely reflects the loss and latency experienced by applications. This occurs because most of the application traffic flows over TCP. In such cases, ICMP provides less accurate results compared to TCP.
TCP protocol requires that TCP packets are sent to a destination port. The default port used by NPM agents is 8084, however you can change this when you configure agents. So, you need to ensure that your network firewalls or NSG rules (in Azure) are allowing traffic on the port. You also need to make sure that the local firewall on the computers where agents are installed is configured to allow traffic on this port.
You can use PowerShell scripts to configure firewall rules on your computers running Windows, however you need to configure your network firewall manually.
In contrast, ICMP does not operate using port. In most enterprise scenarios, ICMP traffic is permitted through the firewalls to allow you to use network diagnostics tools like the Ping utility. So, if you can Ping one machine from another, then you can use the ICMP protocol without having to configure firewalls manually.
In case you are not sure what protocol to use, choose ICMP to start with. If you are not satisfied with the results, you can always switch to TCP later.
How to switch the protocol
If you chose to use ICMP during deployment, you can switch to TCP at any time by editing the default monitoring rule.
To edit the default monitoring rule
- Navigate to Network Performance > Monitor > Configure > Monitor and then click Default rule.
- Scroll to the Protocol section and select the protocol that you want to use.
- Click Save to apply the setting.
Even if the default rule is using a specific protocol, you can create new rules with a different protocol. You can even create a mix of rules where some of the rules use ICMP and another uses TCP.
Data collection details
Network Performance Monitor uses TCP SYN-SYNACK-ACK handshake packets when TCP is chosen and ICMP ECHO ICMP ECHO REPLY when ICMP is chosen as the protocol to collect loss and latency information. Traceroute is also used to get topology information.
The following table shows data collection methods and other details about how data is collected for Network Performance Monitor.
|platform||Direct Agent||SCOM agent||Azure Storage||SCOM required?||SCOM agent data sent via management group||collection frequency|
|Windows||TCP handshakes/ICMP ECHO messages every 5 seconds, data sent every 3 minutes|
The solution uses synthetic transactions to assess the health of the network. OMS agents installed at various point in the network exchange TCP packets or ICMP Echo (depending on the protocol selected for monitoring) with one another. In the process, agents learn the round-trip time and packet loss, if any. Periodically, each agent also performs a trace route to other agents to find all the various routes in the network that must be tested. Using this data, the agents can deduce the network latency and packet loss figures. The tests are repeated every five seconds and data is aggregated for a period of three minutes by the agents before uploading it to the Log Analytics service.
Although agents communicate with each other frequently, they do not generate a lot of network traffic while conducting the tests. Agents rely only on TCP SYN-SYNACK-ACK handshake packets to determine the loss and latency -- no data packets are exchanged. During this process, agents communicate with each other only when needed and the agent communication topology is optimized to reduce network traffic.
Using the solution
This section explains all the dashboard functions and how to use them.
Solution Overview tile
After you've enabled the Network Performance Monitor solution, the solution tile on the OMS Overview page provides a quick overview of the network health. It displays a doughnut chart showing the number of healthy and unhealthy subnetwork links. When you click the tile, it opens the solution dashboard.
Network Performance Monitor solution dashboard
The Network Summary blade shows a summary of the networks along with their relative size. This is followed by tiles showing total number of network links, subnet links and paths in the system (a path consists of the IP addresses of two hosts with agents and all the hops between them).
The Top Network Health Events blade provides a list of most recent health events and alerts in the system and the time since the event has been active. A health event or alert is generated whenever the packet loss or latency of a network or subnetwork link exceeds a threshold.
The Top Unhealthy Network Links blade shows a list of unhealthy network links. These are the network links that have one or more adverse health event for them at the moment.
The Top Subnetwork Links with Most Loss and Subnetwork Links with Most Latency blades show the top subnetwork links by packet loss and top subnetwork links by latency respectively. High latency or some amount of packet loss might be expected on certain network links. Such links appear in the top ten lists but are not marked unhealthy.
The Common Queries blade contains a set of search queries that fetch raw network monitoring data directly. You can use these queries as a starting point for creating your own queries for customized reporting.
Drill-down for depth
You can click various links on the solution dashboard to drill-down deeper into any area of interest. For example, when you see an alert or an unhealthy network link appear on the dashboard, you can click it to investigate further. You'll be taken to a page that lists all the subnetwork links for the particular network link. You will be able to see the loss, latency and health status of each subnetwork link and quickly find out what subnetwork links are causing the problem. You can then click View node links to see all the node links for the unhealthy subnet link. Then, you can see individual node-to-node links and find the unhealthy node links.
You can click View topology to view the hop-by-hop topology of the routes between the source and destination nodes. The unhealthy routes or hops are shown in red so that you can quickly identify the problem to a particular portion of the network.
Network State Recorder
Each view displays a snapshot of your network health at a particular point in time. By default, the most recent state is shown. The bar at the top of the page shows the point in time for which the state is being displayed. You can choose to go back in time and view the snapshot of your network health by clicking on the bar on Actions. You can also choose to enable or disable auto-refresh for any page while you view the latest state.
At each level that you drill-down, you can see the trend of loss and latency for a network link. Trend charts are also available for Subnetwork and Node links. You can change the time interval for the graph to plot by using the time control at the top of the chart.
Trend charts show you a historical perspective of the performance of a network link. Some network issues are transient in nature and would be hard to catch only by looking at the current state of the network. This is because issues can surface quickly and disappear before anyone notices, only to reappear at a later point in time. Such transient issues can also be difficult for application administrators because those issues often surface as unexplained increases in application response time, even when all application components appear to run smoothly.
You can easily detect those kinds of issues by looking at a trend chart where the issue will appear as a sudden spike in network latency or packet loss.
Hop-by-hop topology map
Network Performance Monitor shows you the hop-by-hop topology of routes between two nodes on an interactive topology map. You can view the topology map by selecting a node link and then clicking View topology. Also, you can view the topology map by clicking Paths tile on the dashboard. When you click Paths on the dashboard, you'll have to select the source and destination nodes from the left hand panel and then click Plot to plot the routes between the two nodes.
The topology map displays how many routes are between the two nodes and what paths the data packets take. Network performance bottlenecks are marked in red on the topology map. You can locate a faulty network connection or a faulty network device by looking at red colored elements on the topology map.
When you click a node or hover over it on the topology map, you'll see the properties of the node like FQDN and IP address. Click a hop to see it's IP address. You can choose to filter particular routes by using the filters in the collapsible action pane. And, you can also simplify the network topologies by hiding the intermediate hops using the slider in the action pane. You can zoom-in or out of the topology map by using your mouse wheel.
Note that the topology shown in the map is layer 3 topology and doesn't contain layer 2 devices and connections.
Network Performance Monitor is able to find the network bottlenecks without connecting to the network devices. Based on the data that it gathers from the network and by applying advanced algorithms on the network graph, Network Performance Monitor makes a probabilistic estimate of the parts of network that are most likely the source of the problem.
This approach is useful to determine the network bottlenecks when access to hops isn't available because it doesn't require any data to be gathered from the network devices such as routers or switches. This is also useful when the hops between two nodes are not in your administrative control. For example, the hops may be ISP routers.
Log Analytics search
All data that is exposed graphically through the Network Performance Monitor dashboard and drill-down pages is also available natively in Log Analytics search. You can query the data using the search query language and create custom reports by exporting the data to Excel or PowerBI. The Common Queries blade in the dashboard has some useful queries that you can use as the starting point for creating your own queries and reports.
Investigate the root cause of a health alert
Now that you've read about Network Performance Monitor, let's look at a simple investigation into the root-cause for a health event.
- On the Overview page, you'll get a quick snapshot of the health of your network by observing the Network Performance Monitor tile. Notice that out of the 6 subnetworks links being monitored, 2 are unhealthy. This warrants investigation. Click the tile to view the solution dashboard.
- In the example image below, you'll notice that there is a health event a network link that is unhealthy. You decide to investigate the issue and click on the DMZ2-DMZ1 network link to find out the root of the problem.
- The drill-down page shows all the subnetwork links in DMZ2-DMZ1 network link. You'll notice that for both the subnetwork links, the latency has crossed the threshold making the network link unhealthy. You can also see the latency trends of both the subnetwork links. You can use the time selection control in the graph to focus on the required time range. You can see the time of the day when latency has reached its peak. You can later search the logs for this time period to investigate the issue. Click View node links to drill-down further.
- Similar to the previous page, the drill-down page for the particular subnetwork link lists down its constituent node links. You can perform similar actions here as you did in the previous step. Click View topology to view the topology between the 2 nodes.
- All the paths between the 2 selected nodes are plotted in the topology map. You can visualize the hop-by-hop topology of routes between two nodes on the topology map. It gives you a clear picture of how many routes exist between the two nodes and what paths the data packets are taking. Network performance bottlenecks are marked in red color. You can locate a faulty network connection or a faulty network device by looking at red colored elements on the topology map.
The loss, latency, and the number of hops in each path can be reviewed in the Action pane. Use the scrollbar to view the details of those unhealthy paths. Use the filters to select the paths with the unhealthy hop so that the topology for only the selected paths is plotted. You can use your mouse wheel to zoom in or out of the topology map.
In the below image you can clearly see the root-cause of the problem areas to the specific section of the network by looking at the paths and hops in red color. Clicking on a node in the topology map reveals the properties of the node, including the FQDN, and IP address. Clicking on a hop shows the IP address of the hop.
- UserVoice - You can post your ideas for Network Performance Monitor features that you want us to work on. Visit our UserVoice page.
- Join our cohort - We’re always interested in having new customers join our cohort. As part of it, you'll get early access to new features and help us improve Network Performance Monitor. If you're interested in joining, fill-out this quick survey.
- Search logs to view detailed network performance data records.