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marcwoosnam
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Poor communication between hosts

Hi

We've got a small demo setup (2x ESXi5.1 build 799733 hosts) of vCloud Director running build 5.1.1868405 and are having a strange communication problem with virtual machines when they are sitting on different hosts.

We've tested with multiple organisations and different types of OS etc and the behavior is the same, an example would be that if one of the the VMs is a webserver the website can be displayed if from VMs on the same host, however when on separate hosts the website cannot be displayed. The VMs can ping each other no matter where they are.

I'm hoping that someone here can help point me in the right direction with resolving this

Thanks

Marc

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IamTHEvilONE
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Sounds like your network pool is busted.  If you are using an vApp, Org Routed, or Org Isolated Network ... it sounds like the transport between the two doesn't work.

If the VMs are on one of those network types and on the same host, it works.  If they are on different hosts, it fails.

What type of network pool is this?  VCNI, VXLAN etc?

Make sure that the physical network is actually configured to transport the data.  e.g., VCNI uses a VLAN and MTU of 1524 (suggested min) to transport between hosts.  However, you actually need to configure this on the network fabric (switch, etc).

VXLAN has its own requirements, but has a way to test the virtual wire.

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IamTHEvilONE
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Sounds like your network pool is busted.  If you are using an vApp, Org Routed, or Org Isolated Network ... it sounds like the transport between the two doesn't work.

If the VMs are on one of those network types and on the same host, it works.  If they are on different hosts, it fails.

What type of network pool is this?  VCNI, VXLAN etc?

Make sure that the physical network is actually configured to transport the data.  e.g., VCNI uses a VLAN and MTU of 1524 (suggested min) to transport between hosts.  However, you actually need to configure this on the network fabric (switch, etc).

VXLAN has its own requirements, but has a way to test the virtual wire.

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marcwoosnam
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Thanks for the reply. We're using Org routed with a VCNI network pool.

The MTU is set to 1600 on the VMware side, I have asked the network team to check their end (during installation MTU of 1600 was requested) and will update this thread

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sshellswell
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Check the MTU on the (physical and virtual) switches. VCD-NI & VXLAN need a modification to allow for the extra overhead.

Hope that helps

Steve

marcwoosnam
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Thanks for your help, looks like that's done the trick

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