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VCIX-NV Objective 1.3 Configure and Manage Transport Zones

Covering Objective 1.3 now we will be covering the following topics

  • Create Transport Zones according to a deployment plan
  • Configure the control plane mode for a Transport Zone
  • Add clusters to Transport Zones
  • Remove clusters from Transport Zones

So, beginning with the first point, Create Transport Zones according to a deployment plan. What is a transport zone? Well simply, a transport zone is a virtual fence around the clusters that can talk to each other over NSX. If you want a cluster to be able to talk to other clusters that are on NSX, they must be included in the same transport zone. It is important to note that all VMs included in a cluster that is part of a transport zone will have access to that transport zone. Another thing to be careful of is that while a transport zone can span multiple VDSs, you should be sure that all the clusters that are on that VDS are included in the transport zone. You may run into situations where machines won’t be able to talk to each other otherwise if you have improper alignment.

Shown in the above example, you can see that even though you have the DVS Compute_DVS that spans across 2 clusters, since you add to a transport zone by cluster, it is possible to have just half of the clusters that make up that DVS on the transport zone. This leaves the hosts in Cluster A unable to talk to anyone on the NSX networks.

On to the next point. Configure the control plane mode for a Transport Zone. You can choose between three different control plane modes available.

  • Multicast
  • Unicast
  • Hybrid

These modes control how BUM (Broadcast, Unicast, Multicast) traffic is distributed and more.

Multicast replication mode depends on the underlaying architecture being a full Multicast implementation. The VTEPs on each host join a Multicast group so when BUM traffic is sent, they will receive it. The advantage of this is BUM traffic is only distributed to hosts that participate, possibly cutting the traffic down. Downsides of this are, IGMP, PIM, and Layer 3 Multicast routing are required at the hardware layer adding complexity to the original design.

Unicast replication mode, is everything multicast is not. More specifically, when a BUM packet is sent out, it is sent to every other host on the VXLAN segment. It will then pick a host on the other VXLAN segments and designate it a Unicast Tunnel End Point or UTEP and it will forward the frame to that and then the UTEP will forward it to all other hosts on its VXLAN segment. The advantages of this are not caring about the underlying hardware at all. This is a great thing from the decoupling from hardware standpoint, on the other hand the downside to it is, it uses a lot more bandwidth.

Hybrid replication mode is exactly that. Hybrid. It is a good mix between the above. Instead of needing all the things in multicast, only IGMP is used. Unicast is used between the VXLAN segments to avoid the need for PIM and Layer 3 routing, but internally on the VXLAN segment, IGMP is used and it cuts down on the bandwidth quite a bit. With Hybrid mode, instead of a UTEP being used between segments, it is now called a MTEP or Multicast Tunnel Endpoint.

Unicast is what is used most commonly on smaller networks and Hybrid in larger networks.

As far as adding and removing clusters from Transport Zones, you can do that a different times (adding). You can add when you initially create the transport zone, or you can do it afterwards. If you do it afterwards you will need to be in the Installation sub menu on the navigation menu on the left side of the screen. You then will need to click on the Transport Zones tab and then click on the transport zone you wish to expand. Then click on the Add Cluster icon, which looks like three little computers with a + symbol on the left side. Then select the clusters you wish to add. To remove a cluster, you need to be in the same place, but click on the Remove Clusters icon instead.

That’s the end of section 1. Next up. Section 2. Create and Manage VMware NSX Virtual Networks.

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