Virtualization & Network Storage Technologies | CompTIA Network+ N10-007 | 2.4

In this video you will learn about virtualization & network storage technologies such as: virtual switches, virtual firewalls, virtual NICs, virtual routers, hypervisors, network attached storage, storage area networks, FCoE, Fibre Channel, iSCSI, InifiniBand, & jumbo frames.

Virtual Networking Components

Virtual Switch (vSwitch)

A virtual switch is a software application that allows communication between virtual machines.  A vSwitch does more than just forward data packets, it intelligently directs the communication on a network by checking data packets before moving them to a destination.  vSwitches are usually embedded into installed software, but they may also be included in a server’s hardware as part of its firmware.  A virtual switch is completely virtual anc can connect to a network interface card (NIC).  The vSwitch merges physical switches into a single logical switch.  This helps to increase bandwidth and create an active mesh between server and switches.

Virtual Firewall

A virtual firewall is a network firewall service or appliance running entirely within a virtualized environment and which provides the usual packet filtering and monitoring provided via a physical network firewall.  The virtual firewall can be realized as a traditional software firewall on a guest virtual machine already running, a purpose-built virtual security appliance designed with virtual network security in mind, a virtual switch with additional security capabilities, or a managed kernel process running within the host hypervisor.

Virtual NIC

A virtual NIC uses the host physical network adapter to initiate and manage network communications.  It is created by the operating system or a purpose-built software application.  Once created, it can be used for different applications and networking services.  For instance, a virtual NIC enables a computer to connect to a VPN while being simultaneously connected to another network.  Each of the virtual NICs is considered a unique device, and each has its own separate IP address and network configuration.  In virtualization environments, each virtual machine is generally installed with a virtual network adapter for communication between other virtual machines or with the network itself.

Virtual Router (vRouter)

A virtual router is a software function that replicates in software the functionality of a hardware-based Layer 3 Internet Protocol (IP) routing, which has traditionally used a dedicated hardware device.  Virtual routing is a form of network functions virtualization, in which the functions of traditional hardware-based network appliances are converted to software that can be run on standard commercial off-the-shelf (COTS) hardware.  This has the advantages of lowering hardware costs and allowing more hardware interoperability, rather than requiring a proprietary hardware platform.

Hypervisor

A hypervisor (or virtual machine monitor, VMM) is a computer software, firmware or hardware that creates and runs virtual machines.  A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine.  A virtual machine is a software emulation of the hardware in a working computer. The VMM sets up emulated motherboard chipsets, USB controllers, hard disk host adapters, video cards, and other components of an actual computer as part of the virtual machine (VM), along with setting aside either an expandable or fixed amount of hard disk space. After a hypervisor creates and configures a VM, you install the operating system and apps desired into the VM to have a working emulated computer or virtual machine.  The hypervisor is used to start the virtual machine and, depending on the RAM, processor speed, and features, and available hard disk space in the physical computer, the hypervisor can run several virtual machines at the same time.

There are two types of hypervisors:

  • Type 1 Hypervisor:  a VMM that works directly with the host computer hardware, rather than being installed inside an existing operating system.  Type 1 hypervisors are often referred to as β€œbare-metal” hypervisors.
  • Type 2 Hypervisor:  is a VMM that runs inside an operating system and carves out RAM and disk space from an already-running system.

Network Storage Types

NAS (Network Attached Storage)

A NAS system is a storage device connected to a network that allows storage and retrieval of data from a centralized location for authorized network users and clients.  NAS is a self-contained storage device that contains one or more drives, a network interface, and is bundled with software to enable computers on the network to access the device. A NAS device built for use in business may have two or more drive bays, permit easy upgrading of drives, and might also provide for automatic mirroring (copying) of the contents of one drive to another (RAID 1).

SAN (Storage Area Network)

Storage area networks are sometimes referred to as networks behind the servers and historically developed out of a centralized data storage model, but with its own data network.  A SAN is, at its simplest, a dedicated network for data storage.  In addition to storing data, SANs allow for the automatic backup of data, and the monitoring of the storage as well as the backup process.  A SAN is a combination of hardware and software.  SANs are primarily used to access data storage devices, such as disk arrays and tape libraries from servers so that the devices appear to the operating system as direct-attached storage.  A SAN typically is a dedicated network of storage devices not accessible through the LAN.  Although a SAN provides only block-level access, file systems built on top of SANs do provide file-level access and are known as shared-disk file systems.

Connection Type

FCoE (Fibre Channel over Ethernet)

Fibre Channel over Ethernet is a computer network technology that encapsulates Fibre Channel frames over Ethernet networks.  This allows Fibre Channel to use 10 Gigabit Ethernet networks (or higher speeds) while preserving the Fibre Channel protocol.  Also, Fibre Channel is designed as a channel interface.  That is, it guarantees lossless delivery of frames with a predictable latency.  Since classical Ethernet had no priority-based flow control, unlike Fibre Channel, FCoE required enhancements to the Ethernet standard to support a priority-based flow control mechanism (to reduce frame loss from congestion).

Fibre Channel (FC)

Fibre Channel is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data.  Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data centers.  Fibre Channel networks form a switched fabric because the switches in a network operate in unison as one big switch.  Fibre Channel typically runs on optical fiber cables within and between data centers, but can also run on copper cabling.  Supported data rates include 1, 2, 4, 8, 16, 32, 64, & 128 Gigabit per second resulting from improvements in successive technology generations.

iSCSI (Internet Small Computer Systems Interface)

In computing, iSCSI is an IP-based storage networking standard for linking data storage facilities.  It provides block-level access to storage devices by carrying SCSI commands over a TCP/IP network.  iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances.  It can be used to transmit data over LANs, WANs, or the Internet and can enable location-independent data storage and retrieval.  The protocol allows clients (called initiators) to send SCSI commands to storage devices (targets) on remote servers.  It is a storage area network (SAN) protocol, allowing organizations to consolidate storage into storage arrays while providing clients (such as database and web servers) with the illusion of locally attached SCSI disks.  It mainly competes with Fibre Channel, but unlike traditional Fibre Channel which usually requires dedicated cabling, iSCSI can be run over long distances using existing network infrastructure.

InfiniBand (IB)

InfiniBand is a computer networking communications standard used in high-performance computing that features very high throughput and very low latency.  It is used for data interconnect both among and within computers.  InfiniBand is also used as either a direct or switched interconnect between servers and storage systems, as well as an interconnect between storage systems.  It is designed to be scalable and uses a switched fabric network topology.  InfiniBand offers throughput of up to 2.5 Gigabytes per second and support for up to 64,000 addressable devices.  Because it is also scalable and supports quality of service (QoS) and failover, InfiniBand is often used as a server connection in high-performance computing environments.

Jumbo Frame

In computer networking, jumbo frames are Ethernet frames with more than 1500 bytes of payload.  Commonly, jumbo frames can carry up to 9000 bytes of payload, but smaller and larger variations exist.  Many Gigabit Ethernet network interface controllers and some Fast Ethernet switches and Fast Ethernet network interface cards can support jumbo frames.  Each Ethernet frame must be processed as it passes through the network.  Processing the contents of a single large frame is preferable to processing the same content broken up into smaller frames, as this makes better use of available CPU time by reducing interrupts.  This also minimizes the overhead byte count and reduces the number of frames needing to be processed.  This is analogous to physically mailing a packet of papers instead of several single envelopes with one sheet each, saving envelopes and cutting sorting time.