Hi,

When I launch a Discover in The Dude my main switch is discovered and some device are correctly connected to like this :
This allow me to monitor the bandwidth from and to each device. However most device do not have their own link to the switch, but they are all linked to a single subnetwork cloud that is in turn connected to the switch. Also, if I run a new discover to find devices that were not running during the original discover lots of devices get connected to already existing subnetwork clouds.

Is there anyway to have The Dude connect each device to the switch on their own link/cloud except when devices really share a port in the switch (wireless devices for exemple)?

Thanks,

Mathieu Pagé

I have not used autodiscover since the first time I played with The Dude for the reasons you are talking about. I have always manually connected devices together to end up with a layer 1/Layer 2 representation of my networks, rather than the Layer 3 representation that The Dude builds through the autodiscovery process.

I have not used autodiscover since the first time I played with The Dude for the reasons you are talking about. I have always manually connected devices together to end up with a layer 1/Layer 2 representation of my networks, rather than the Layer 3 representation that The Dude builds through the autodiscovery process.

Hi, thanks for your answer.

I could manually link all the device, but I would not know which port on the switch each device is connected to. Is there a way to get this information in The Dude?

Mathieu Pagé

It could be done but may take you a while unless you can do some tricky scripting.

Every device you have mapped in The Dude will show you its MAC address. This is found on the device's "General" tab.

If you have SNMP read access to your switches then open up the switch settings dialogue, select the "SNMP" tab, then the "Bridge fdb" sub-tab. The Bridge fdb (forwarding database) shows each MAC address that the switch has learned and the port that it has been found on.

Match up the MAC of the device to the port where the MAC appears in the Bridge fdb and you then know which switchport the device is connected to.

Maybe the MikroTik guys can whip up a device location tool for us in their copious quantities of free time

It could be done but may take you a while unless you can do some tricky scripting.

Every device you have mapped in The Dude will show you its MAC address. This is found on the device's "General" tab.

If you have SNMP read access to your switches then open up the switch settings dialogue, select the "SNMP" tab, then the "Bridge fdb" sub-tab. The Bridge fdb (forwarding database) shows each MAC address that the switch has learned and the port that it has been found on.

Match up the MAC of the device to the port where the MAC appears in the Bridge fdb and you then know which switchport the device is connected to.

Maybe the MikroTik guys can whip up a device location tool for us in their copious quantities of free time

Again, thanks for your answer.

While time consuming this is a good solution to my problem, however for some reason only 10 entries appear in the Bridge Fdb tab while I have about 45 devices connected to the switch (or to other device themselve connected to the switch like the wireless access point).

Does anyone have any idea why I don't see all entries?

Edit : Just wanted to add that when I click on the find button (the one with binoculars), not the refresh button a different sets of entries appears. Each time Between 5 and 20 "random" entries appears.

Mathieu Pagé

The forwarding database cache has a timeout (5 minutes by default on my switches - but can be shorter or longer). It may be that your end devices are not very "chatty" or your switches may have a short fdb timeout. So if an end device has not sent a packet for longer than the timeout its entry will disappear from the fdb. Then when it does send a packet it will appear back in the fdb till it times out again.

I would pick a device, set up a continuous ping to it so that it is sending packets through the switch, find it in the fdb and set up the link you want. Then stop the ping and move on to the next device.

It is also possible that your network is flooded with traffic and you are losing some of the SNMP replies (SNMP being a UDP protocol is susceptible to packet loss).

Or maybe your switches have very high CPU utilisation for some reason and are not able to generate the SNMP responses correctly.

The forwarding database cache has a timeout (5 minutes by default on my switches - but can be shorter or longer). It may be that your end devices are not very "chatty" or your switches may have a short fdb timeout. So if an end device has not sent a packet for longer than the timeout its entry will disappear from the fdb. Then when it does send a packet it will appear back in the fdb till it times out again.

I would pick a device, set up a continuous ping to it so that it is sending packets through the switch, find it in the fdb and set up the link you want. Then stop the ping and move on to the next device.

It is also possible that your network is flooded with traffic and you are losing some of the SNMP replies (SNMP being a UDP protocol is susceptible to packet loss).

Or maybe your switches have very high CPU utilisation for some reason and are not able to generate the SNMP responses correctly.

Hi, It seems the Forwarding Database is cleared every couples of seconds or so. I've got the same problem when I look at the fdb in the web ui of my switch. Unfortunately, the same behavior continues even when I set the Aging limit to 600 seconds in the switch UI.

I'll try your idea of using a ping to ensure the devices entry stay in the fdb.

Thanks again for your help,

Mathieu Pagé