VMWARE NETWORKINGVMware ESX/ESXi networking features allow virtual machines to communicate with other virtual and physical machines, allow management of the ESX/ESXi host, and allow the VMkernel to access IP-based storage and perform VMware vMotion migrations. Failure to properly configure ESX/ESXi networking can negatively affect virtual machine management and storage operation.

Networking Terminology

vSphere Standard Switch: A software-based switch that resides in the VMkernel and provides traffic management for VMs. Users must manage vSphere Standard Switches independently on each ESXi host.

vSphere Distributed Switch: A software-based switch that resides in the VMkernel and provides traffic management for VMs and the VMkernel. Distributed vSwitches are shared by and managed across entire clusters of ESXi hosts.

Port/Port Group: A logical object on a vSwitch that provides specialized services for the VMkernel or VMs. A virtual switch can contain a VMkernel port or a VM port group. On a vSphere Distributed Switch, these are called distributed port groups.

VMkernel Port: A specialized virtual switch port type that is configured with an IP address to allow hypervisor management traffic, vMotion, iSCSI storage access, network attached storage (NAS) or Network File System (NFS) access, and vSphere Fault Tolerance (FT) logging. A VMkernel port is also referred to as a vmknic VM Port Group: A group of virtual switch ports that share a common configuration and allow VMs to access other VMs or the physical network.

Virtual LAN: A logical LAN configured on a virtual or physical switch that provides efficient traffic segmentation, broadcast control, security, and efficient bandwidth utilization by providing traffic only to the ports configured for that particular virtual LAN (VLAN).

Trunk Port (Trunking): A port on a physical switch that listens for and knows how to pass traffic for multiple VLANs. It does this by maintaining the 802.1q VLAN tags for traffic moving through the trunk port to the connected device(s). Trunk ports are typically used for switch-to-switch connections to allow VLANs to pass freely between switches. Virtual switches support VLANs, and using VLAN trunks allows the VLANs to pass freely into the virtual switches.

Access Port: A port on a physical switch that passes traffic for only a single VLAN. Unlike a trunk port, which maintains the VLAN identification for traffic moving through the port, an access port strips away the VLAN information for traffic moving through the port.

Network Interface Card Team: The aggregation of physical network interface cards (NICs) to form a single logical communication channel. Different types of NIC teams provide varying levels of traffic load balancing and fault tolerance.

vmxnet Adapter: A virtualized network adapter operating inside a guest operating system (guest OS). The vmxnet adapter is a high-performance, 1 Gbps virtual network adapter that operates only if VMware Tools have been installed. The vmxnet adapter is sometimes referred to as a paravirtualized driver. The vmxnet adapter is identified as Flexible in the VM properties.

vlance Adapter: A virtualized network adapter operating inside a guest OS. The vlance adapter is a 10/100 Mbps network adapter that is widely compatible with a range of operating systems and is the default adapter used until the VMware Tools installation is completed.

e1000 Adapter: A virtualized network adapter that emulates the Intel e1000 network adapter. The Intel e1000 is a 1 Gbps network adapter. The e1000 network adapter is the most common in 64-bit VMs.

An ESXi networking examplevSphere Standard SwitchesvSphere standard switches(vSwitches) provide the connectivity to provide communication as follows:

Between VMs within an ESXi host Between VMs on different ESXi hosts

Between VMs and physical machines on the network

For VMkernel access to networks for vMotion, iSCSI, NFS, or Fault Tolerance logging (and management on ESXi)Comparison of vSwitches and physical switchesvSwitchesPhysical Switches

vSwitch functions at layer 2Functions at layer 2

Maintains MAC address tablesMaintains MAC address tables

Supports VLAN configurationsSupports VLAN configurations

A vSwitch does not support the use of dynamic negotiation protocols for establishing 802.1q trunks or port channels, such as Dynamic Trunking Protocol (DTP) or Link Aggregation Control Protocol (LACP).Supports both

A vSwitch does not need to perform Internet Group Management Protocol (IGMP) snooping because it knows the multicast interests of the VMs attached to itCan use IGMP

Port and Port GroupsA vSwitch allows several different types of communication, including communication to and from the VMkernel and between VMs. To help distinguish between these different types of communication, ESXi uses ports and port groups. A vSwitch without any ports or port groups is like a physical switch that has no physical ports; there is no way to connect anything to the switch, and it is, therefore, useless.Port groups differentiate between the types of traffic passing through a vSwitch, and they also operate as a boundary for communication and/or security policy configuration. The two different types of ports and port groups that you can configure on a vSwitch:

VMkernel port

VM port group

Uplinks

VMs in the ESXi host cannot communicate with the physical network without uplinks. vSwitches must be connected to the ESXi host's physical NICs as uplinks to communicate with the rest of the network.Unlike ports and port groups, uplinks aren't required for a vSwitch to function. Physical systems connected to an isolated physical switch with no uplinks to other physical switches in the network can still communicate with each otherjust not with any other systems that are not connected to the same isolated switch. Similarly, VMs connected to a vSwitch without any uplinks can communicate with each other but not with VMs on other vSwitches or physical systems.

This sort of configuration is known as an internal-only vSwitch. It can be useful to allow VMs to communicate only with each other. VMs that communicate through an internal-only vSwitch do not pass any traffic through a physical adapter on the ESXi host.A vSwitch bound to at least one physical network adapter allows VMs to establish communication with physical servers on the network or with VMs on other ESXi hosts.The vSwitch associated with a physical network adapter provides VMs with the amount of bandwidth the physical adapter is configured to support. All the VMs will share this bandwidth when communicating with physical machines or VMs on other ESXi hosts. In this way, a vSwitch is once again similar to a physical switch. For example, a vSwitch bound to a network adapter with a 1 Gbps maximum speed will provide up to 1 Gbps of bandwidth for the VMs connected to it; similarly, a physical switch with a 1 Gbps uplink to another physical switch provides up to 1 Gbps of bandwidth between the two switches for systems attached to the physical switches.

A vSwitch can also be bound to multiple physical network adapters. In this configuration, the vSwitch is sometimes referred to as a NIC team. A vSwitch can have a maximum of 32 uplinks. In other words, a single vSwitch can use up to 32 physical network adapters to send and receive traffic from the physical switches. Binding multiple physical NICs to a vSwitch offers the advantage of redundancy and load distribution.

A vSwitch using NIC teaming has multiple available adapters for data transfer. NIC teaming offers redundancy and load distribution.