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Showing posts from April, 2016

VLAN tagging in VMware vSphere

Introduction In a physical environment all the servers have dedicated physical NIC that are connected to a physical switch. VLANs in physical world are usually controlled by setting the VLAN ID on the physical switch port and then setting the server’s IP address to correspond to that NIC’s VLAN. But in a virtual environment, dedicating a physical NIC (pNIC) to each VM that resides on the host is not possible. In reality, a physical NIC of the Esxi host service many VMs, and these VM’s may need to be connected to different VLANs. So the method of setting a VLAN ID on the physical switch port doesn’t work. To counter this issue, 802.1Q VLAN tagging comes in picture in virtual environment. Before digging deep into 802.1Q VLAN tagging lets understand how networking works in a virtual environment. An Esxi host typically can have more than one physical network adapters for redundancy, load balancing and segregation. The physical NICs (pNICs) are connected to physical switches and

VMware NIC Teaming and Load Balancing Policies in virtual switch

NIC Teaming In its simplest terms NIC teaming means that we are taking multiple physical NICs on a given ESXi host and combining them into a single logical link that provides bandwidth aggregation and redundancy to a vSwitch. NIC teaming can be used to distribute load among the available uplinks of the team.  A NIC teaming configuration can look like as shown in below screenshot: There are several Load Balancing policies available for the virtual switch. These are discussed as below: 1: Route Based on Originating virtual Port-ID : This is the default load balancing policy for a vSS or vDS. This policy doesn’t require any special configuration to be done at virtual switch level or physical switch level. In this policy when a NIC is added to a VM or a new VM is provisioned with a NIC and comes online, VMkernel assigns a Port-ID to the virtual NIC of the VM. The outgoing traffic from the VM NIC will be routed through which uplink (physical adapter) of the team is determine