VLAN’s enable a single physical LAN segment to be further isolated so that groups of ports are isolated from one another as if they were on physically different segments. Using VLAN’s, administrator get following advantages:

• Integrates the host into a pre-existing environment
• Isolate and secure network traffic
• Reduce network traffic congestion

In a physical environment, servers are equipped with dedicated physical NIC that are in turn 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.

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.… Read More

NetFlow is a mechanism to analyze network traffic flow and volume to determine where traffic is coming from, where it is going to, and how much traffic is being generated. NetFlow-enabled routers export traffic statistics as NetFlow records which are then collected by a NetFlow collector.

Traffic flows are defined as the combination of source and destination IP addresses, source and destination TCP or UDP ports, IP, and IP Type of Service (ToS). Network devices that support NetFlow, tracks and report information on the traffic flows, and send this information to a NetFlow collector. Using the data collected, network admins gain detailed insight into the types and amount of traffic flows across the network.

Netflow was originally developed by Cisco and has become a de-facto industry standard for analysing network traffic. VMware introduced Netflow for vDS in vSphere v5.

Note: Netflow is only supported with vDS and not standard switches.

There are various versions of NetFlow ranging from from v1 to v10.… Read More

I am currently going through VCAP 6 objective 3.2 and the very firts task in this objective is to deploy a LAG and Migrate to LACP. Although I have read about this in past and we use this in our production environment, I never got a chance to configure this in my homelab because of hardware restrictions (this is true till date 🙁

Well before jumping into LACP configuration, lets discuss a bit about few networking terms here (networking was/is always a big headache for me).

• Link Aggregation Group (LAG): The simplest definition of LAG can be defined as bonding of ethernet links in order to achieve greater throughput.
• Link Aggregation Control Protocol (LACP): This is a protocol which is defined in the 802.1AX standard, and it provides a method for automating LAG configurations. LACP-capable devices discover each other by sending LACP packets (called  LACPDUs) to the Slow_Protocols_Multicast address 01-80-c2-00-00-02. They then negotiate the forming/not forming of the LAG.

vStorage API for Array Integration (VAAI) is an API framework developed by VMware that enables certain storage tasks to be offloaded from Esxi hosts to the storage array and thus lessens the processing workload on the Esxi host. VAAI was first introduced with vSphere 4.1.

It significantly improves the performance of storage -intensive operations such as cloning storage, block zeroing , and so on and thus reduces the overhead on the ESXi host. The main goal of VAAI is to help storage vendors to provide hardware assistance to speed up VMware I/O operations.

The APIs create a separation of duty between the hypervisor and its storage devices, enabling each to focus on what it does best: virtualization-related tasks for the hypervisor and storage-related tasks for the storage arrays.

What vSphere functions can be offloaded with VAAI?

1: Copy offload: Certain operations such as deploying a new VM from template or cloning a VM etc involves copying of virtual disk files.… Read More