2.1 Describe device virtualization technologies
📘CCNP Encore (350-401-ENCORE-v1.1)
1. What Is a Hypervisor?
A hypervisor is software that allows multiple virtual machines (VMs) to run on one physical device (server, laptop, or desktop).
Each virtual machine:
- Has its own operating system
- Has its own CPU, memory, and storage (virtual)
- Works as if it were a separate physical computer
The hypervisor:
- Controls access to physical hardware
- Allocates resources to each VM
- Keeps VMs isolated from each other
2. Why Hypervisors Are Important in IT Networks
In enterprise networks:
- Servers are virtualized to save cost and space
- Multiple services run on one physical server
- Network devices and services are tested using VMs
- Data centers rely heavily on virtualization
For CCNP ENCOR, you must understand:
- Types of hypervisors
- How they work
- Where they are used
- Key differences
3. Types of Hypervisors
There are two main types:
- Type 1 Hypervisor (Bare-Metal Hypervisor)
- Type 2 Hypervisor (Hosted Hypervisor)
4. Type 1 Hypervisor (Bare-Metal Hypervisor)
4.1 Definition
A Type 1 hypervisor:
- Runs directly on physical hardware
- Does not need a host operating system
- Controls the hardware by itself
The hypervisor is the first software layer installed on the device.
4.2 How Type 1 Hypervisor Works
- Physical server powers on
- Type 1 hypervisor loads directly on hardware
- Virtual machines run on top of the hypervisor
- Each VM runs its own operating system
There is no Windows or Linux host OS in between.
4.3 Key Characteristics of Type 1 Hypervisor
- Runs directly on hardware
- Very high performance
- Low latency
- Strong isolation between VMs
- Highly secure
- Designed for enterprise environments
4.4 Common Type 1 Hypervisors (Exam-Relevant)
- VMware ESXi
- Microsoft Hyper-V (Server/Core)
- KVM (Kernel-based Virtual Machine)
- Xen
4.5 Where Type 1 Hypervisors Are Used
In IT environments such as:
- Data centers
- Enterprise server farms
- Cloud platforms
- Virtualized network services
- Production environments
4.6 Advantages of Type 1 Hypervisor
- Best performance
- Direct hardware access
- High scalability
- Strong security
- Minimal overhead
- Stable for long-term workloads
4.7 Disadvantages of Type 1 Hypervisor
- Requires dedicated hardware
- More complex to install and manage
- Not designed for personal desktop use
5. Type 2 Hypervisor (Hosted Hypervisor)
5.1 Definition
A Type 2 hypervisor:
- Runs on top of an existing operating system
- Depends on the host OS for hardware access
The hypervisor is an application, not the main system software.
5.2 How Type 2 Hypervisor Works
- Physical device boots
- Host operating system loads (Windows, Linux, macOS)
- Type 2 hypervisor runs as software inside the host OS
- Virtual machines run on the hypervisor
Hardware access goes through the host OS first.
5.3 Key Characteristics of Type 2 Hypervisor
- Requires a host OS
- Easy to install
- Uses host OS drivers
- Lower performance than Type 1
- Suitable for testing and learning
5.4 Common Type 2 Hypervisors (Exam-Relevant)
- VMware Workstation
- Oracle VirtualBox
- VMware Fusion
- Parallels Desktop
5.5 Where Type 2 Hypervisors Are Used
In IT environments such as:
- Network labs
- Testing environments
- Training systems
- Development machines
- Exam practice setups
5.6 Advantages of Type 2 Hypervisor
- Easy to install
- Runs on normal desktops or laptops
- Good for testing and learning
- No dedicated server required
5.7 Disadvantages of Type 2 Hypervisor
- Lower performance
- More resource overhead
- Depends on host OS stability
- Less secure than Type 1
- Not ideal for production use
6. Type 1 vs Type 2 Hypervisor (Exam Comparison)
| Feature | Type 1 Hypervisor | Type 2 Hypervisor |
|---|---|---|
| Runs on hardware | Yes | No |
| Requires host OS | No | Yes |
| Performance | Very high | Moderate |
| Security | Very strong | Lower |
| Enterprise use | Yes | No |
| Desktop/lab use | No | Yes |
| Example | VMware ESXi | VirtualBox |
7. Key Exam Points to Remember (Very Important)
For CCNP ENCOR exam:
- Type 1 = Bare-metal
- Type 2 = Hosted
- Type 1 is used in data centers
- Type 2 is used for testing and labs
- Type 1 offers better performance and security
- Type 2 depends on host OS
- VMware ESXi = Type 1
- VirtualBox = Type 2
8. Simple Summary (For Non-IT Learners)
- A hypervisor allows many virtual computers to run on one physical machine
- Type 1 runs directly on hardware
- Type 2 runs on top of another operating system
- Type 1 is faster and stronger
- Type 2 is easier to use and learn
- Both are important in IT networking
