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Module 13: Network Virtualization - Coggle Diagram
Module 13: Network Virtualization
13.1 Cloud Computing
13.1.3 Cloud Services
Platform as a Service (PaaS) - The cloud provider is responsible for providing users access to the development tools and services used to deliver the applications. These users are typically programmers and may have control over the configuration settings of the cloud provider’s application hosting environment.
Infrastructure as a Service (IaaS) - The cloud provider is responsible for giving IT managers access to the network equipment, virtualized network services, and supporting network infrastructure. Using this cloud service allows IT managers to deploy and run software code, which can include operating systems and applications.
Software as a Service (SaaS) - The cloud provider is responsible for access to applications and services, such as email, communication, and Office 365 that are delivered over the internet. The user does not manage any aspect of the cloud services except for limited user-specific application settings. The user only needs to provide their data.
13.1.4 Cloud Models
Public clouds - Cloud-based applications and services offered in a public cloud are made available to the general population. Services may be free or are offered on a pay-per-use model, such as paying for online storage.
Private clouds - Cloud-based applications and services offered in a private cloud are intended for a specific organization or entity, such as the government. A private cloud can be set up using the organization’s private network, though this can be expensive to build and maintain.
Hybrid clouds - A hybrid cloud is made up of two or more clouds (example: part private, part public), where each part remains a separate object, but both are connected using a single architecture. Individuals on a hybrid cloud would be able to have degrees of access to various services based on user access rights.
Community clouds - A community cloud is created for exclusive use by a specific community. The differences between public clouds and community clouds are the functional needs that have been customized for the community. For example, healthcare organizations must remain compliant with policies and laws (e.g., HIPAA) that require special authentication and confidentiality.
13.1.2 Cloud Overview
Cloud computing involves large numbers of computers connected through a network that can be physically located anywhere. Providers rely heavily on virtualization to deliver their cloud computing services. Cloud computing can reduce operational costs by using resources more efficiently.
Cloud computing addresses a variety of data management issues:
Enables access to organizational data anywhere and at any time
Streamlines the organization’s IT operations by subscribing only to needed services
Eliminates or reduces the need for onsite IT equipment, maintenance, and management
Reduces cost for equipment, energy, physical plant requirements, and personnel training needs
Enables rapid responses to increasing data volume requirements
13.1.5 Cloud Computing versus Data Center
The terms data center and cloud computing are often used incorrectly. These are the correct definitions of data center and cloud computing:
Data center: Typically, a data storage and processing facility run by an in-house IT department or leased offsite.
Cloud computing: Typically, an off-premise service that offers on-demand access to a shared pool of configurable computing resources. These resources can be rapidly provisioned and released with minimal management effort.
Data centers are the physical facilities that provide the compute, network, and storage needs of cloud computing services. Cloud service providers use data centers to host their cloud services and cloud-based resources.
A data center can occupy one room of a building, one or more floors, or an entire building. Data centers are typically very expensive to build and maintain.
For this reason, only large organizations use privately built data centers to house their data and provide services to users. Smaller organizations that cannot afford to maintain their own private data center can reduce the overall cost of ownership by leasing server and storage services from a larger data center organization in the cloud.
13.3 Virtual Network Infrastructure
13.3.1 Type 1 Hypervisors
Type 1 hypervisors are also called the “bare metal” approach because the hypervisor is installed directly on the hardware.
Type 1 hypervisors are usually used on enterprise servers and data center networking devices.
13.3.2 Installing a VM on a Hypervisor
When a Type 1 hypervisor is installed, and the server is rebooted, only basic information is displayed, such as the OS version, the amount of RAM, and the IP address. An OS instance cannot be created from this screen.
Type 1 hypervisors require a “management console” to manage the hypervisor. Management software is used to manage multiple servers using the same hypervisor.
The management console can automatically consolidate servers and power on or off servers as required.
13.3.3 The Complexity of Network Virtualization
Server virtualization hides server resources, such as the number and identity of physical servers, processors, and OSs from server users.
This practice can create problems if the data center is using traditional network architectures.
Another problem is that traffic flows differ substantially from the traditional client-server model.
Typically, a data center has a considerable amount of traffic being exchanged between virtual servers, such as the UCS servers shown in the figure.
13.4 Software-Defined Networking
13.4.2 Control Plane and Data Plane
A network device contains the following planes:
Control plane
This is typically regarded as the brains of a device. It is used to make forwarding decisions. The control plane contains Layer 2 and Layer 3 route forwarding mechanisms.
Data plane
Also called the forwarding plane, this plane is typically the switch fabric connecting the various network ports on a device.
Layer 3 Switch and CEF
SDN and Central Controller
13.4.4 Traditional and SDN Architectures
In a traditional router or switch architecture, the control plane and data plane functions occur in the same device. Routing decisions and packet forwarding are the responsibility of the device operating system. In SDN, management of the control plane is moved to a centralized SDN controller.
13.4.3 Network Virtualization Technologies
VMware developed a virtualizing technology that enabled a host OS to support one or more client OSs. Most virtualization technologies are now based on this technology.
Two major network architectures have been developed to support network virtualization:
Software-Defined Networking (SDN)
A network architecture that virtualizes the network, offering a new approach to network administration and management that seeks to simplify and streamline the administration process.
Cisco Application Centric Infrastructure (ACI)
A purpose-built hardware solution for integrating cloud computing and data center management.
Components of SDN may include the following:
OpenFlow
This approach was developed at Stanford University to manage traffic between routers, switches, wireless access points, and a controller. The OpenFlow protocol is a basic element in building SDN solutions. Search for OpenFlow and the Open Networking Foundation for more information.
OpenStack
This approach is a virtualization and orchestration platform designed to build scalable cloud environments and provide an IaaS solution. OpenStack is often used with Cisco ACI. Orchestration in networking is the process of automating the provisioning of network components such as servers, storage, switches, routers, and applications. Search for OpenStack for more information.
Other components
Other components include Interface to the Routing System (I2RS), Transparent Interconnection of Lots of Links (TRILL), Cisco FabricPath (FP), and IEEE 802.1aq Shortest Path Bridging (SPB).
13.2 Virtualization
13.2.3 Server Virtualization
Server virtualization reduces the number of physical servers by running multiple virtual machines (VMs) on a single hardware platform using hypervisors. It optimizes resources, improves fault tolerance through redundancy, and allows dynamic management of services. This approach significantly enhances efficiency and scalability in IT infrastructure.
13.2.4 Advantages of Virtualization
Reduced Costs
Virtualization reduces the need for physical servers, networking devices, and infrastructure, lowering maintenance costs, energy usage, and data center space.
Additional Benefits
It enables faster server provisioning, improves uptime with redundancy, enhances disaster recovery, extends legacy system lifespan, and simplifies testing in isolated environments.
13.2.2 Dedicated Servers
Virtualization arose to address issues in traditional servers, where each ran a dedicated OS and service. These setups suffered from single points of failure and server sprawl, wasting resources and space due to underuse.
13.2.5 Abstraction Layers
Virtualization can be explained through abstraction layers in computer architecture: Services, OS, Firmware, and Hardware. These layers work together to enable virtual environments.
13.2.1 Cloud Computing and Virtualization
Previously, cloud services and models were covered. Virtualization, the foundation of cloud computing, separates the OS from hardware, enabling dynamic resource provisioning. AWS exemplifies this by offering on-demand virtual servers and applications.
13.2.6 Type 2 Hypervisors
Type 2 hypervisors are popular with consumers and for testing virtualization as they don't require management console software. Examples include Virtual PC, VMware Workstation, and Oracle VM VirtualBox. Many are free, but advanced features may come at a cost. Ensure the host machine has sufficient resources to run VMs effectively.
13.5 Controllers
13.5.1 SDN Controller and Operations
Centralizes control of data flows between the control plane and the data planes of switches and routers.
13.5.2 Cisco ACL
Cisco ACI addresses the need for network automation, faster application deployment, and aligning IT infrastructure with business objectives.
13.5.3 Core Components of ACI
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Application Network Profile (ANP): Represents network configurations, such as VLANs, web services, and applications, though actual ANPs can be more complex.
Application Policy Infrastructure Controller (APIC): Acts as the centralized software controller in ACI architecture.
Cisco Nexus 9000 Series Switches: Provide an application-aware switching fabric.
13.5.4 Spine-Leaf Topology
