Dropped packets when Netflow enabled on Meraki MX450

[George Bradlink]

[size=150]Hi:

We have connected six ports of a Meraki MX450, each using the same VLAN, to our WS-26-400-AC.

We’re seeing that when we have two or more links attached between the same VLAN (1) and two separate interfaces on a Meraki MX450 device that the netflow traffic from the MX450 is causing a large number of packet drops and inconsistent connectivity, even when just pinging our local gateway on the Meraki– which is directly attached to the switch. If we connect only one port between the devices, the packets don't get dropped. Wondering if it could be a packets per second limit on either the UDP traffic, or, since the netflow collector is currently down, if it could be the broadcast ARP traffic causing the issue. The Meraki device is attempting to re-ARP for the IP of the collector about every three seconds.

Thanks for your thoughts.

George

[Stephen]

What version of firmware is the switch running?

[George Bradlink]

1.5.5

[Stephen]

This doesn't sound exactly the same in behavior but it's probably worth taking a look here: viewtopic.php?f=17&t=6243

In summary though, try re-installing 1.5.5 or upgrade to the latest 1.5.6.rc2 (both of which can be found here: viewtopic.php?f=17&t=240) and see if that fix's it.

[George Bradlink]

I will try and let you know. Thanks,

George

[George Bradlink]

Hi Stephen:

I upgraded the firmware and the trouble still exists.

Thank you,

George

[George Bradlink]

We turned Netflow off on the MX450 and the trouble still happens.

We have 6 ports on the Meraki MX450 connected to 6 ports on the WS-26. We also have a laptop connected to one other port on the WS-26 running a continuous ping to the WS-26, the MX450 and 8.8.4.4. The pings to the WS-26 work without trouble. The pings through the WS-26 to the MX450 and 8.8.4.4 will fail about 40-50% of the time.

If we disconnect all but one of the links between the MX-450 and the WS-26, the pings to all locations work fine.

Thanks again,

George

[Stephen]

Clearly the issue is in relation to the WS-26 and the MX-450. Unfortunately, I doubt I could get approval to get one of those based on the price. So I can't make any suggestions for it and it's possible the issue could be there, especially since it is a firewall.

However, on the WS-26 potentially experimenting with the Storm Control options in the Configurations tab might help. My guess, disabling pause frames or enabling loop protection might be worth a try.

[George Bradlink]

Thanks Stephen:

We'll look in that direction. Please let us know if anything else comes to mind.

George