Last week I provided an overview of the routing tools for Network Performance Monitor 10.5 and this week I will walk you through a troubleshooting scenario using the Interactive Online Demo to help illustrate how you can use these tools to troubleshoot real world issues in your own environment.

 

Obviously, routing is one of the keys to a properly functioning network. IP packets on your network must be routed, not only to their given destinations, but should also arrive in the fastest way possible. The new Routing tools for NPM have combined the Logical and Physical layers to help you get things done.

 

Troubleshooting Walk-Through


Troubleshooting StepsImage
  1. Let’s first take a look at the High Errors and Discards Today resource located about halfway down the page on the NPM Summary Tab in Orion.
    1. Notice the node labeled “Router5.lab.local” has a significant amount of discards.
    2. Click on “Router5.lab.local” (hereafter referred to as “Router 5”) to drill down and see the Node Details Page for that Router.
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2. Once on the Node Details page, click on the Network Tab.

 

The Network Sub View is where all of the Routing Resources are located.

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3. As it so happens, “Router 5” has some issues transmitting packets.


The "STATUS" column of the Current Percent Utilization of Each Interface resource (middle of the page) shows two “Down” interfaces.

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4. Checking the Routing Table, we can see that the Down interfaces ( FastEthernet0/0 - Fa0/0 and FastEthernet0/1 - Fa0/1 ) do not actually appear in the Routing Table.


(hint all of the interfaces in the routing table shown are "1/0" and the two down interfaces are 0/0 and 0/1 respectively).


This is good news in this case, since the Down status of those particular interfaces is not actually affecting routing.

 

The fact that the Routing Table shows all GREEN and the subnets are properly routed to the other interfaces on this device is a quick way to make that determination.

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So not only does NPM provide the fundamental set of information needed to define routing – showing protocol, destination, subnet size, next hop and interface information -  it also combines node information allowing visibility into the real availability of nodes and interfaces. Hovering over elements, such as interfaces, activate Pop Ups (image on the right) providing more details and a performance overview.

 

With these resources available at our fingertips, NPM is now doing all the heavy lifting. No longer do we have to manually connect to routers via command line to pull in this data and we do not have to share a router’s credentials with the guy in IT three floors down!

 

Everything is real time and polled frequently, by default every 2 minutes but configurable to meet your particular needs.

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5. We have determined our Routing Table is clean, so now let’s take a look at the Routing Neighbors resource which shows you the status of the routers that are directly “next” to the one you are viewing. In this instance we have:

 

  • Router 2 as one of our neighbors using the OSPF protocol.
  • And the second neighbor 74.115.12.1 which is using the BGP Protocol.

 

The fact that the second neighbor, running BGP shows up as IP Address 74.115.12.1 actually tells us that Orion is not monitoring this device as a node. If it were being monitored in NPM we would could drill down and view its Node Details Page as we can with Router2.lab.local.

 

The point here is that if you notice something like this in your own environment you would want to have NPM monitor it so all of that extra information is available to you.

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Note: To fully monitor the router 74.115.12.1 - or any other device - you can go to the Admin section of NPM and either:

 

  1. Run a manual discovery via "Add a Node"
  2. Run an automated discovery via Sonar Network Discovery
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6. Now let’s check out the Top 10 Flapping Routes resource.

 

Flapping details are usually something that cannot be obtained directly from the router, and some other kind of analysis tool is needed to get this info. But now with NPM all of this is available in one place.

 

By providing the number of “Flaps” (how many times the path was announced for this particular router) insight can be gained into serious issues that need attention right now or emerging issues which might become more serious down the road.

 

In the image to the right, notice that for Destination Network 10.0.0.0 we can see 8 Flaps to Router2.lab.local.

 

From here, we could drill down into Router 2 for details about the interfaces, the statistics and historical data to find out what is going on to prevent further Flapping from occurring.

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7. Finally, we might check the Default Route Change resource to learn if the default route has been added/removed/changed and if so when.

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“Wonder Twin Powers… Activate!”

One final thought. Once you find out the source of a given Routing issue the next step you need to make, more often than not, is connecting to one or many routers and make configuration changes to finally resolve the issue.

 

If you have ever had to do this, you know that connecting to routers one by one via command line can be a major pain. So, it is worth pointing out that if you own SolarWinds Network Configuration Manager (NCM) you can fix problems such as duplicate subnet routing or add missing subnets more easily by pushing out new configurations through NCM directly to your routers without having to go through the slow and tedious process of manually connecting to each of your devices as you would have to do without using NCM.

 

These two tools used together, NPM and NCM, can save you a lot of time and frustration while helping you keep your network running smoothly. Oh, and if you were wondering about the “Wonder Twin Powers” reference, it is an old Saturday morning cartoon and

this video explains it quite well.