Thursday, August 8, 2013

VMware ESX - Server Virtual Networking

Virtual Networking Overview
This is one of the most important issues when you using VMware or plan to jump into it , pay attention to this post and take the points you think can help you.

Networking on a regular infrastructure (No Virtualization)

·         Every computer have Physical Ethernet card (NIC).

·         This Ethernet card connected to a Physical switch(via cable –from the Nic into the wall….Your company switch)

·         The Physical switch connected to a management Physical/Real LAN network

Networking on a Virtualize infrastructure (Go Virtualization!)

What are virtual networks?

·         One of the Biggest  features  VMware virtualization has to offer .  

·         You can achieve Fix ability you cannot allow in a physical networking .

Virtual Networking Terms – vmnic, vswitch, vswif & port group

·         VMware NIC (vmnic) – physical NIC in the ESX server –this is not a virtual NIC.

We can locate the physical NIC:

Go to you ESX server -> Network Adapters-> Configuration TAB

·         Virtual Switch (vswitch) - here we can see all the HOSTS connecting to the Vswitch(when  you create new VM you must specify the vswitch the VM will connect to).

·         Service console virtual interface (vswif0\1=Important) - this is unique virtual NIC for managing the server (Virtual Center or SSH). Without the “vswif0” you cannot control the ESX server (Esx1(vswif1) = SC , Esx2 (vswif1) = SC

Note !
            If you deleted this Virtual Interface you will lose the connection for the VC!

·         Port group’s names (VM network, Service Console, and Kernel) but you can create your own – port groups name is called a “Network Label” –we create this primary to identify the Virtual Networks that crated inside VMware server. The default port group created by the ESX server and called “Network” (allow you to add this Vnic so hosts can get external access to the internet).

·         Virtual NIC in each VM maps to a port group name:

Host Virtual nic -> maps to a port group (Vmnetwork by default) -> the VM network -> connected to a Virtual Switch -> connected to the Physical ESX NIC.

Virtual networking Must Know

·         Migration with Vmotion\iScasi features required a VMkernel port

ESX Server->Networking->”Add networking”

·         You can have MAXIMUM switches on a single host.

·         The Vswitch can be connected to one or more physical NICs on the ESX server (Redundancy, Low balancing).

·         VMware standard virtual NIC is the AMD PCnet32 network adapter.
Virtual Networking Configuration Scenarios

·         Private/Host-only

o   Vswitch not connected to any physical NIC

o   Excellent for testing & development

o   VMs must all be on the same server of course

·         Single NIC(Most Common)

o   1 NIC

o   You get traffic shaping

·         Multiple NICs

o   Load balanced

o   Increased performance

o   Redundancy
Using VLANs with ESX

·         VLANs create logical grouping of ports / devices rather than being forced into physical groupings.

·         Each grouping of ports is a separate broadcast domain as all devices in that VLAN are not the same broadcast domain and subnet.

·         Many larger companies use VLAMs for greater performance and security of their networks.

·         VMware ESX supports VLAN networking and can work with your existing VLAN design .

·         VMware ESX offers offers 802.1Q trucking .

·         For devices on different VLANs to communicate ,they must go through a router on a trunk port. Typically this router is a L3 Switch or traditional router on your LAN however ,with VMware , it could also be a virtual router , such as a Vyatta open source Linux router ,running in a VM.

·         VMware Whitepaper and VLAN solutions can be found at
To use VLANs
Configuration-> chose vSwitch -> properties –Virtual Machine Network-> Edit-> VLAN ID-> enters vlan number.

All VM connected to this vSwith will configure to the VLAN we assigned and can communicate only  between them .


1 comment:

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