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Packet loss from Azure vMX to spokes

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Kind of a big deal

Packet loss from Azure vMX to spokes

I wonder if anyone else has run into this problem before.

 

I have a client using a vMX in Azure and they are reporting 4% packet loss to all the VMs in Azure from the spokes.  It doesn't matter which VM is being pinged, and it doesn't matter which spoke the ping is being done from.  Spokes can ping other spokes with zero packet loss.

The issue happens consistently 24x7.  You do about 100 pings and you will loose about 4 of the packets.  The packet loss tends to be spread out.

 

If you do a ping within the Meraki dashboard there is zero packet loss between the vMX and any spoke that I test.  There are no interesting events in the event viewer, and the status bar for the vMX and spokes is solid green.

 

The VMs in Azure can ping the vMX with zero packet loss.  The issue only happens when traffic is routed through the vMX to a remote spoke (or from a remote spoke being routed through the vMX to the Azure VMs).

 

The vMX and all MX's are running 14.39.  I have tried rebooting the vMX and a small selection of MX's.  I have also had a small number of the Windows VMs rebooted.  The VMs are running different versions of Windows Server as well (so there is nothing in common).

Nothing has made a difference.

 

 

Any one had issues with small amounts of packet loss to VMs in Azure connected via a vMX?

5 REPLIES 5
Meraki Employee

Re: Packet loss from Azure vMX to spokes

Hey @PhilipDAth

 

Not sure if you have resolved this yet, but out of curiosity, do you see the same pattern of packet loss with other type of traffic? such as telnet or TCP

 

Do the spokes have multiple uplinks? if so, create a SD-WAN policy to push traffic to vMX via a specific uplink. Or test from a spoke that has a single uplink and see if there's any difference.

 

Cheers,

 

-Alex

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Kind of a big deal

Re: Packet loss from Azure vMX to spokes

No, it is not resolved.  I just did a packet capture on the VMX and it does not appear to be affecting TCP traffic.  Only ICMP ping traffic.

 

All spokes have dual uplinks.  The spokes are in more than one country and using more than one ISP.

 

We do have an SD-WAN policy applied.

 

To me it appears to be an issue with VMX running in Azure.  If I promote some spokes to hubs, there is no loss between them.  That is the only common point.

Meraki Employee

Re: Packet loss from Azure vMX to spokes

It's interesting that it's only affecting ICMP traffic and only in Azure.

If you have a support case opened already for this one, I would recommend continue working with the support team. Sounds like this one might involve collaboration between Meraki & Azure support.

If you can PM me the case info (please don't post it publicly here), I'll be happy to follow-up with the support team for you.

Cheers,

-Alex
If this was helpful, click the Kudos button below.
Please mark it as a solution if solved your issue so others can benefit from it Smiley Happy
Kind of a big deal

Re: Packet loss from Azure vMX to spokes

>If you have a support case opened already for this one,

 

I did have a support case open.  We can ping between the public IP address of the VMX and the public IP address on the spokes with no packet loss.  We can ping between VMX to the spokes over AutoVPN with no packet loss.

After that the support person said it is not a Meraki issue and closed the case.

 

I'll probably let it rest now.  I was just wondering if others were having an issue.

Meraki Employee

Re: Packet loss from Azure vMX to spokes

Sounds good, I'll let others chime in if they've seen the same behavior.
If it becomes a bigger issue (e.g if it affects more than just ICMP traffic), I'd say reopen the support case and go from there.

Cheers,

-Alex
If this was helpful, click the Kudos button below.
Please mark it as a solution if solved your issue so others can benefit from it Smiley Happy
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