11 Replies Latest reply: May 4, 2012 2:23 PM by TreyJ RSS

what are tunnels on routers?

krfitzgerald

I have several routers that have a tunnel resource showing up and showing an impossible utilization of over $3900 percent. It has a designation of Tunnel1 - Tu2. What is this and how can I troubleshoot it?

 
  • Re: what are tunnels on routers?
    HemiTruck

    these are usually vpn tunnels

    all you need to do is set the bandwdth for the tunnel (manually if you need to)

    if it is on a spoke then asign the same bandwidth as the link to the spoke

    if it is the hub then go with the max ethernet link you have on the device.

    • Re: what are tunnels on routers?
      krfitzgerald

      I don't think these are vpn tunnels but I don't know for sure. How can I verify that?

      • Re: what are tunnels on routers?
        Andy McBride

        You need to examine the interface configs on the device. Look for IPSec and/or VPN configuration.

        • Re: what are tunnels on routers?
          krfitzgerald

          I tried to login to the interface and I got a message that says % this interface cannot be modified. I did a show config from enable mode and I didn't see interface tu2 anywhere. this is an MPLS router so I doubt there would be any vpns on it. What else could this be?

          • Re: what are tunnels on routers?
            Andy McBride

            Ah - try show MPLS interfaces. It is an MPLS tunnel.

            Here is a good blog about MPLS tunnnels. MPLS Tunnels Explained

            • Re: what are tunnels on routers?
              krfitzgerald

              I tried show mpls interfaces and it did not like the mpls. What else could the command be? Also, these are throwing alot of alerts for utilization way over 100%. Any ideas to correct that off the top of your head? do i need to increase something on the router or adjust something in solarwinds?

              • Re: what are tunnels on routers?
                TreyJ

                They may be GRE tunnels.  If you do a "show IP interface brief", you'll see the list of tunnels.  Then if you do a "show interface tunnelxxx" you can see what the bandwidth is being reported.  They're probably set to the default value.

                • Re: what are tunnels on routers?
                  krfitzgerald

                  this is looking good. the recieve and transmit bandwidth is set to 8000 kbps. I can see the txload is 255/255, does that mean the transmit is maxed out? should I adjust the max on the router? I'm assuming the the router will not allow the tunnel to use more than the 8000 kbps even if the interface has available bandwidth?

                  • Re: what are tunnels on routers?
                    TreyJ

                    Do you know what your up/down speed is of your internet connection?  If so, you can do this:  go into config mode and into the tunnel interface.  Then say "bandwidth nnnnnn" to set the correct bandwidth. That number needs to be in bits per second.  If it's a DSL connection, this will be your transmit speed.  Then you can enter "bandwidth receive nnnnnnn" for your download speed.  Some IOS versions also allow you to set "tunnel bandwidth transmit nnnnnnn" and "tunnel bandwidth receive nnnnnn".  After that is set, you can make those values custom values for the tunnel interfaces in Orion.  Although I seen cases where Orion will poll the router and auto change that value.

                    • Re: what are tunnels on routers?
                      krfitzgerald

                      I adjusted the custom bandwidth on all the tunnel interfaces to match what I found in the routers and they all came down to normal numbers except for one. One is howing 100% on the transmit. How do I confirm this in the router and should I increase it?

                      • Re: what are tunnels on routers?
                        TreyJ

                        When you do a "show interface tunnelxxx", you should see two lines.  One starts with "5 minute input rate" and the other starts with "5 minute output rate".  Those values will show you what rate data is actually flowing in and out of that interface.  It is a 5 minute average, but if the interface is maxed out, you should be able to tell pretty quickly.  If it is maxed out, there is something on your networking uploading and/or downloading quite a bit of data.