VMware vNetwork Distributed Switch Architecture

VMware vNetwork Distributed Switch Architecture

                  Now let’s look at a diagram that shows the distributed switch architecture which is driven from the datacenter level and is the recommended architecture to use when you are setting up your vNetwork.

First off we have distributed switches. A distributed switch acts as a single virtual switch across all associated hosts. This allows virtual machines to maintain consistent network configuration as they migrate across hosts. Like a standard switch, a distributed switch is a network hub for virtual machines. A distributed switch can route traffic internally between virtual machines or link to an external network.

 Distributed switches are managed entities configured inside of vCenter Server.

 Distributed switches exist across two or more clustered ESX or ESXi hosts. vCenter Server owns the configuration of distributed switches, and the configuration is consistent across all hosts. The uplink ports on the distributed switch link to uplink ports on hidden vSwitches. The hidden vSwitch uplink ports connect to physical NICs, which then connect to the physical switch ports.

Be careful not to confuse a distributed switch with a single switch spanning across several hosts. Two virtual machines on different hosts can communicate with each other only if both virtual machines have uplinks in the same broadcast domain. Consier a distributed switch as a template for the network configuration on each ESX or ESXi host.

 Each distributed switch includes distributed ports. A distributed port represents a port to which you can connect any networking entity, such as a virtual machine, the service console, and so on. vCenter Server stores the state of distributed ports in the vCenter Server database, so networking statistics and policies migrate with virtual machines when moved from host to host. This network vMotion feature is key to implementing state-dependent features such as inline IDS/IPS firewalls, and third-party virtual switches.

Distributed port groups perform the same functions as port groups in standard vSwitches:

1. They provide a way to logically group distributed ports to simplify configuration,
2. They inherit and can override all distributed switch properties,

And they do not constitute the means to segregate traffic within the distributed switch (unless you use Private VLANs).