Virtual network concepts & standard virtual switch

Networking is one of the most important aspects of the business.  This module will discuss about virtual networking features.  How virtual machine and hosts are communicating between internal and external network.  Before starting the virtual network, just have a glance into the physical network.  Please keep it in mind there is no change in virtual network and physical network concept.

For EXAMPLE : 

Look the above figure : There are three halls in a building each halls we have some physical desktop connect to a physical switch. Now required to interconnect all the desktops located in each halls.  All the physical switches uplink together or interconnect to a core switch to achieve that goal.  (Point highlighted here is Neither IP address, not assigning any uplink ports, nor one uplink cable split and connects to two switches).  Uplinks have only one function transparent bridging between the switches.  Now assume each hall as a single ESX / ESXi server running multiple virtual machines instead of physical desktops.  Virtual machines have virtual NIC that connect to vSwitch instead of physical switch. Virtual switch connected to uplink port (uplink port is physical NIC with each ESX server).     Note : ESX / ESXi physical NIC act as a uplink, however no IP address assigning to physical NIC,  one uplink not able to map multiple vSwitch.

vNetwork provides several different types of services to host and VM’s, like connecting virtual machine, vmkernel and service console  to physcial network. 

vNetwork support two type vSwitches

1.       vNetwork standard switch : A switch creating and configuring in individual host level.

2.       vNetwork Distributed switch : Similar to virtual standard switch but it functions as a single switch across the hosts.  This allows virtual machines to maintain consistent network configuration as they migrate across multiple host.  This switch is designed and configured in vCenter server.

All communication whether it is internal virtual machines or external virtual machines networks, must be defined through a virtual switch.    Configure NIC teaming required multiple physical NIC’s for load balancing and redundancy. vSwitch have maximum of 4088 ports by default 56 ports per switch,  each network entity connected to a switch used a port from the vSwitch.     

vStandard switch components :

 vStandard switch components are configured at the host level.  Configure multiple uplink ports (Network adapters) and connection type (virtual machine network, Service console and VMkernel port) in a single vSwtich.  Application and Guest operating system can communicate to vNIC through a standard device driver or VMware optimized drivers.  Create VMkernel port for VMotion & IP based storages (ISCSI, NFS).   During installation ESX server will create a vSwitch0 includes connection type service console (vswif0) for management network and VM network port group for virtual machine network by default.  vSwitch 0 contain 22 ports and always mapped to vmnic0 (1^st Physical NIC) by default.

 When create a standard vSwitch, required define a single connection type.  Later add additional connection type like Service console, VMkernel and multiple Virtual machine port groups in a single vSwitch .  Port groups are number ports where virtual machines are connected.  This is appropriate solution to configure different network policies and assign VLAN id for group virtual machine in virtual infrastructure. Planning the design the virtual machine network partly depends on the layout of your physical networks. 

For EXAMPLE:

Physical server with enough network cards, plan multiple switches and segregate each connection type.  Physical server with limited network cards creates a single vSwitch with multiple port groups. Isolate or segment the network traffic using VLAN (ESX support 802.1 Q standard).  

Physical NICs are assigned at the virtual switch level, so all port and port groups defined for a particular switch share the same hardware.  Configure NIC teaming policy for map single or multiple physical NIC to port groups.  If required configure physical NIC options like unused and standby to specific port groups or port.  NIC teaming in virtual network the physical switch which we connected to uplink should be link aggravation (802.3AD) enabled.

There are 3 different types of connection types. 

1.       Service console port for management network

2.       VMkernel port for VMotion network, fault tolerance and IP based storage access

3.       Virtual Machine port group for inter connect virtual machines between internal and external network.

Service console and VMkernel port required IP address for communication.

·         Properties :  Edit current configuration or add and remove new connection type and network adapters

·         Remove  : Delete the vSwitch from the host.

·         Callout    : icon near the port group provide information about the port group properties and network policies like traffic shaping, security  & load balancing

·         Callout of the network adapter: If CDP enable ESX server it will show all the details of the Network adapter.  If uplink connected to a cisco switch it will provide detailed information about that switch capability like device type, protocol information, type of bridging etc..

In summary virtual networking ultimately relies on the physical network infrastructure.  However, required many information from the network administrator to complete the virtual network configuration.