chapter 3 Flashcards
what is An ESXi hos
It takes one physical server and creates multiple (VMs) on it.
Each VM gets its own space with CPU, memory, storage, and network, all running independently.
Physical network devices like routers, switches and load balancers are virtualized using …
hypervisors.
hypervisor vs esxi
esxi is A Specific Hypervisor: ESXi is a type 1 hypervisor created by VMware.
Creating a virtual network on top of a physical network is known as …
overlay networking.
Network virtualization works in cloud environments and can be managed by …
[ CMPs ] Cloud Management Platform
how is Network virtualization is different from VLANs.
Imagine an office building.
- Virtual Network: creates separate floors in the building using software.
- VLAN: A VLAN is like dividing a single floor (say, Finance) into sections with curtains.
What is Software-Defined Networking?
SDN
use of software to control and manage networks, similar to network virtualization.
SDN Vs Network Virtualization:
- Focus: SDN focuses on controlling the network.
- Focus: Network virtualization focuses on creating virtual networks on top of a physical network.
… offers more flexibility than … and why?
SDN , network virtualization
- as it doesn’t require full hardware virtualization.
Network virtualization benefits:
Flexibility
Scalability
Isolation
Portability
what are the two popular overlay protocols.
- Virtual Extensible Local Area Network (VXLAN)
- Generic Network Virtualization Encapsulation (GENEVE)
how does VXLAN allow for many more virtual networks than VLANs.
- uses 24-bit VNIs (Virtual Network Identifiers)
… is vendor-neutral and has been recognized as RFC (Request for Comments) 7348.
VXLAN
A VXLAN ID is called a …
VXLAN Network Identifier (VNI).
VXLAN … and GENEVE … connect the overlay to the underlay network.
- endpoints (VTEPs) &
- tunnel endpoints (TEPs)
… uses VXLAN while … uses GENEVE.
NSX-V , NSX-T
Virtualized Data Centers overcome challenges like …
cost, complexity, inefficiency, and inflexibility.
… is a leader in SDDC technology, offering agility and instant provisioning for data centers.
VMware
Fully-Virtualized Data Center: key characteristics?
Software-Defined
Built-in Security
Scalability
.
Modern Technology Support: Supports containers, cloud-native applications, and infrastructure as code.
in which layers Data remains data at these upper layers.
5, 6, 7
what happens in Layer 4 (Transport):
Data is segmented into pieces called segments and headers are added containing port information for applications.
what happens in Layer 3 (Network):
Segments are encapsulated with IP addresses, identification numbers, and other routing information to become packets.
what happens in Layer 2 (Data Link):
Packets are encapsulated with MAC addresses and error-correction data to become frames.
encapsulation
As data travels down the layers, headers are added for routing and functionality at each layer
VMs need a virtual network component to connect to the real network and communicate with other devices.
t
There are three main ways to connect VMs to a physical network:
bridged network,
NAT network, and
host-only network.
explain Bridged networks:
In a bridged network, the VM shares the same network as the host computer and uses the host’s IP address.
This allows VMs to communicate with other devices on the network just like any other computer.
explain Network Address Translation (NAT) networks:
Limited IP situation: Useful when you have a limited number of public IP addresses available.
Private network: VMs have private IP addresses within a separate network created on the host computer (VMnet).
External network communication: A NAT device translates private VM addresses to the host computer’s public IP.
Data packet handling: The NAT device sorts and sends data packets to the correct VMs within the VMnet.
What is NAT’s Network layout
A VM connects to a virtual switch (vSwitch) via a virtual network interface card (vNIC).
explain Host-only Network section:
Creates a private network for VMs on the host computer only, similar to a NAT network but without internet access.
Internal Communication in Host-only Network section:
VMs can communicate with each other within the host-only network using virtual network adapters (vNICs).
… Useful for creating isolated virtual environments where VMs don’t need external network access.
Host-only Network section:
in what network does A DHCP server assigns IP addresses to the devices on the network.
- Host-only Network section: and
- NAT
… act like central connection points, allowing VMs to connect with each other and the external network.
vSwitches
by default, each ESXi host has what type of vSwitch?
has a single vSwitch named vSwitch0.
data transfer in vSwitch?
Similar to a physical switch, vSwitches process Layer 2 data frames and have organized ports grouped into port groups.
what’s meant by vSwitch’s Configuration Flexibility:
vSwitches allow adjustments to Virtual Local Area Networks (VLANs), security settings, load balancing, and Maximum Transmission Units (MTU) sizes, influencing data packet sizes.
Functionality of vSwitch
It can handle internal traffic between VMs on the same or different ESXi hosts, and also forwards traffic between VMs and physical machines or external networks.
Components of vSwitch
Port Groups: Groups of virtual ports that VMs connect to. Each port group can utilize one or more physical NICs for network traffic.
VMkernel Adapters: Special ports used by the hypervisor to connect services (vMotion, management, storage) to the network.
Uplink Ports: Connect the standard switch to physical network adapters (NICs) on the ESXi host.
The number of ports on a standard switch can dynamically adjust to optimize resource usage on the ESXi host.
t
A standard switch has two functional sections:
Data Plane and
Management Plane
… Handles tasks like packet switching, filtering, and tagging for VLANs.
data plane
management plane
The administrative interface where you configure the data plane’s functions (security policies, etc.)
explain vSphere Distributed Switch (or vDS)
- Imagine you have a big apartment building (data center) with many floors (ESXi hosts).
- each floor will have A standard switch (vSwitch)
- A vSphere Distributed Switch (vDS) is like having one central switchboard for the entire building.
adv of vDS
Centralized Management
scalability
granular policies
simplified management
A vCenter Server can support up to … vDSes, each managing up to …. port groups.
128
2,000 hosts and 10,000
what is NSX Logical Switching / NSX Logical Switches?
- Is a network virtualization technology
- These create virtual networks (broadcast domains) for VMs, similar to physical switches but with more flexibility.
In NSX Logical Switching …. and … protocols encapsulate VM traffic and enable communication across different physical networks.
VXLAN (NSX-V) & GENEVE (NSX-T)
NSX Logical Routing
Enables VMs on different networks (subnets) to communicate directly within the hyperviso
NSX-V Uses … for routing
NSX Edge
Imagine NSX Edge as a central traffic director for your network, managing how data flows to and from your servers
NSX Edge can be … or …
a Distributed Logical Router (DLR) or
an Edge Services Gateway (ESG).
…. provides East-West routing (VM traffic within the same data center).
Distributed Logical Router (DLR)
explain ESG (Edge Services Gateway)
- North-South Traffic
- offers gateway services (DHCP, NAT, VPN, load balancing) for connecting isolated networks.
NSX-T: Introduces a two-tier routing architecture: explain
- Tier-0 router: Manages North-South traffic (between data center and external world).
- Tier-1 router: Manages East-West traffic (within the data center), connecting to tier-0 or directly to logical switches.
tier 0 and tier 1 routers reside on …
transport nodes (ESXi hosts or NSX Edges).
Tier-0 supports … routing
static routing and eBGP Border Gateway Protocol
… are like gatekeepers at the edge of a data center, controlling traffic flow and security.
edge routers
NSX virtualizes edge routing function with:
NSX-V: NSX Edge Services Gateway (ESG) appliances that provide various network services.
NSX-T: NSX Edge appliances similar to ESG but not the same.
explain ECMP (Equal-Cost Multipath) in NSX-V
uses multiple paths between physical and virtual networks to improve traffic flow / faster data transfer
Routing Protocols of NSX-V and NSX-T
NSX-V: Uses OSPF (Open Shortest Path First) to efficiently route traffic within the data center.
NSX-T: Uses BGP (Border Gateway Protocol) to handle routing between different data centers or organizations.
… can do both internal-to-external (source NAT) and external-to-internal (destination NAT) translation.
NSX-V ESG
NSX load balancer
Distributes traffic across multiple servers to prevent overload and ensure high availability
Acts like a traffic director, sending requests to healthy servers in the pool.
NSX Load Balancing: Integrates with other NSX services and offers features like
High availability for the load balancer itself.
Support for various applications (TCP, UDP).
Multiple health check options.
Third-party vendor integration.
