TheVMinator
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Expert

NSX installation

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Where are all the places I need to configure MTU size to 1600 before installing NSX?  Or do they need to be configured before I install NSx manager and NSX controllers?

THanks!

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grosas
Community Manager
Community Manager

In your one host scenario you may never see encapsulation happening.  The 1600 MTU requirement is for encapsulation to work.

I refer you to the following slide (the blue arrow is erroneously pointing to VM3) for an explanation of what happens within your one host.

Screen Shot 2016-03-15 at 5.16.10 PM.png

HTH!

_____________________________________ Gabe Rosas Blog: hcx.design LinkedIn: /in/gaberosas Twitter: gabe_rosas

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larsonm
Expert
Expert

The MTU of 1600 is required where any VXLAN traffic will traverse, usually among VTEPs.  If the VTEPs on host A are on a different switch than the VTEPs on host B, and they need to communicate, everything in the path, whether it's a switch or a router, will require a maximum MTU size of 1600.

The NSX Manager and NSX Controllers do not require an MTU of 1600 for communication. 

The design guide is a good source of answers:

https://www.vmware.com/files/pdf/products/nsx/vmw-nsx-network-virtualization-design-guide.pdf

TheVMinator
Expert
Expert

OK but if I just have one host, and traffic between VMs doesn't leave the host - do I still need to configure 1600 MTU anywhere?  I will send traffic to and from VMs on the host from the physical network.  (Traffic between VMs stays on the host, but traffic between vms and physical systems will leave the host)

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showard1
Enthusiast
Enthusiast

You'd just need to do it on the overall DVS that has your VTEP on it.  BTW I usually don't do 1600.  I just do 9000 everywhere because telling the network team I need Jumbo Frames usually ends up being simpler than a weird number like 1600.

Also, just FYI you don't need to raise the MTU if all you are using is the Distributed Firewall.  Its only needed for VXLAN traffic.

grosas
Community Manager
Community Manager

In your one host scenario you may never see encapsulation happening.  The 1600 MTU requirement is for encapsulation to work.

I refer you to the following slide (the blue arrow is erroneously pointing to VM3) for an explanation of what happens within your one host.

Screen Shot 2016-03-15 at 5.16.10 PM.png

HTH!

_____________________________________ Gabe Rosas Blog: hcx.design LinkedIn: /in/gaberosas Twitter: gabe_rosas

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