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Module 13: Network Virtualization, image, image - Coggle Diagram

- - - - SDN builds on the concept of virtual network infrastructure. It separates the control plane (decision-making logic, managed by the CPU) from the data plane (actual packet forwarding, handled by hardware).
      - The control plane manages routing protocols, topology tables, STP, ARP, and forwarding decisions.
      - The data plane handles traffic forwarding using instructions from the control plane, without CPU involvement.
      - This separation allows for more centralized and flexible network management.
      - Layer 3 Switch and Cisco Express Forwarding (CEF)
        
        CEF is a high-performance Layer 3 IP switching technology that allows packet forwarding to happen in the data plane, without involving the control plane.
        
        The control plane builds the routing and ARP tables.
        
        These tables are used to pre-populate the FIB (Forwarding Information Base) and adjacency table in the data plane.
        
        This allows fast, efficient packet forwarding by the data plane.
        
        SDN and Central Controller:
        
        SDN separates the control plane from individual network devices and centralizes it in a controller.
        
        Devices handle data forwarding only.
        
        The central controller manages routing, policies, security, and flow control across the network.
        
        This approach improves flexibility, visibility, and security.
        
        13.4.4 Traditional and SDN Architectures:
        In traditional networks, the control plane and data plane are integrated into the same device, with the device's OS handling both routing decisions and packet forwarding.
        In SDN, the control plane is centralized in an SDN controller, which manages how switches and routers forward traffic.
        
        SDN Framework and APIs
        
        The SDN controller acts as a central brain that:
        
        Communicates upward with applications via northbound APIs (used for traffic shaping and service deployment).
        
        Communicates downward with network devices via southbound APIs, such as OpenFlow, to control data plane behavior.
        
        APIs enable flexibility, automation, and programmability across the network.
      - 13.4.3 Network Virtualization Technologies
        
        Two main network virtualization architectures include:
        
        Software-Defined Networking (SDN):
        
        Cisco Application Centric Infrastructure (ACI):
        
        Key SDN Components:
        
        OpenFlow: Protocol developed to manage traffic between network devices and a central controller—foundational to many SDN solutions.
        
        OpenStack: A platform for virtualization and orchestration used to build scalable cloud environments, often paired with Cisco ACI.
        
        Other technologies: Include I2RS, TRILL, Cisco FabricPath, and Shortest Path Bridging (SPB)—all contributing to efficient, scalable virtual networking.
- - - - PaaS (Platform as a Service): Platforms for application development.
      - SaaS (Software as a Service): Software accessible via subscription or browser (like Office 365)
      - IaaS (Infrastructure as a Service): On-demand virtual computing.
    - - It mentions two types of cloud:
        
        Public (available to everyone)
        
        Private (exclusive to specific organizations)
    - - Type 2 (applications running on an operating system)
      - Type 1 (installed directly on the hardware)
  - - - Its main benefits include
        
        Cost reduction in equipment, maintenance, and management.
        
        Lower energy consumption and reduced physical space requirements
        
        IT optimization, subscribing only to necessary services.
        
        Improved responsiveness to increasing data demands.
        
        Remote access to data anytime and anywhere.
  - - - Additionally, ITaaS (IT as a Service) extends cloud services to IT support, enabling businesses to scale operations without investing in new infrastructure, personnel training, or software licensing. These services are available on demand, cost-efficient, and accessible worldwide without compromising security.
      - SaaS (Software as a Service): Users access applications like email and Office 365 over the internet, without managing cloud infrastructure.
      - PaaS (Platform as a Service): Developers use cloud-based tools to build applications, controlling configuration settings
      - IaaS (Infrastructure as a Service): IT managers access virtualized computing resources to run operating systems and applications.
  - - - Private clouds: Reserved for specific organizations, like governments, and can be hosted on private networks or managed externally with strict security.
      - Hybrid clouds: A mix of public and private clouds, allowing controlled access to different services within a unified system
      - Public clouds: Services accessible to anyone via the internet, either free or pay-per-use (e.g., online storage).
      - Community clouds: Designed for specific communities with customized security and compliance needs (e.g., healthcare organizations meeting HIPAA requirements).
- - - - 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.
    - - 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.