cloud

Question 1

What is an InfiniBand?

Answer 1

Virtualised storage technology that uses a switched fabric topology and very high throughput (+600 G/s) and very low latency –> BIG DATA

Very expensive, mainly used in major cloud/ data centres

Question 2

What is VoIP?

Answer 2

VoIP digitises voice traffic to be treated like other data on the network.

Paired with SIP (UDP 5060 - 5061)

RTP (Session layer) H.323, H.264

Question 3

elasticity vs scalability

Answer 3

elasticity; ST, charging on per user basis at the end of the month : matching resources with the actual needs at any given point in time

scalability: LT, ability to step up and handle sudden increase in workload

Question 4

vertical scaling vs horizontal scaling

Answer 4

vertical scaling: adding better components (more RAM) to handle the extra load

horizontal scaling: load balancing, adding an extra server

provides more redundancy and less downtime, but more tricky to set up

Question 5

Infrastructure as Code (IaC)

Answer 5

• enables managing and provisioning of infrastructure through code (instead of manual)
• scripted automation and orchestration

Question 6

Private-Direct Connection

Answer 6

extends preexisting on-prem data centre into the cloud provider’s network to directly connect to your VPC

better (but more expensive) than vpn

• > faster, better performance
• supports multiple vpcs
• better redundancy

!more expensive

Question 7

What is SDN?

What protocol is used?

Answer 7

Software defined networking:

enables the network to be centrally controlled through software (SND controller) using APIs and SBIs (Southland Programming Interfaces)

protocol: OpenFlow

Question 8

SD-WAN

Answer 8

1. control plane functions are decoupled from the routers and performed by SD-WAN Controller
2. Physical WAN connections can use a variety of technologies (4G, 5G, MPLS, etc)
3. . SD-WAN controller can simultaneously send out appropriate configuration commands to routers to provide consistent QoS, security and predictable performance

Question 9

3 layers of a distributed control plane?

vs centralised control plane in SDN

Answer 9

1. management plane: monitor traffic conditions and status of the network, configure and manage the devices (ex. SSH into the CLI to configure the router)
2. control plane: routing, traffic prioritisation, security (ex. OSPF, STP)
3. data plane/ infrastructure layer: physically handles N traffic (forwarding data, encrypting, NAT)

Question 10

SBI vs NBI

Answer 10

Southbound Intefaces (SDN controller –> routers and switches) | OpenFlow

vs Northbound Interfaces (applications –> SDN controller) | RESTful API | JSON

Question 11

High availability protocols

Answer 11

• FHRP (First Hop Redundancy Protocol)
– Your computer is configured with a single default gateway
– We need a way to provide availability if the default gateway fails

• VRRP (Virtual Router Redundancy Protocol)
– The default router isn’t real
– Devices use a virtual IP for the default gateway
– If a router disappears, another one takes its place – Data continues to flow

Question 12

NAS vs SAN

Answer 12

NAS (file-level), using TCP/IP

vs SAN (block-level), using specialised fiber optic cables

vs Fiber channel FCoE fiber channel over Ethernet, or iSCSI (low cost, jumbo frame, but slower 10Gbps)

–> requires a lot of bandwidth, ideally isolated network and high-speed connection

Question 13

Which of the following cloud services should an organization choose in order to develop a new iPhone app without having to configure and set up their own development environment?

Answer 13

Platform as a Service (PaaS) is a complete development and deployment environment in the cloud, with resources that enable you to deliver everything from simple cloud-based apps to sophisticated, cloud-enabled enterprise applications.

Question 14

Which of the following technologies allows an administrator to create virtual machines by abstracting the operating system and applications from the underlying hardware?

Answer 14

A hypervisor is hardware, software, or firmware capable of creating virtual machines and then managing and allocating resources to them. A hypervisor is a function that abstracts the operating system and applications from the underlying computer hardware.

Question 15

Which of the following is a computing environment where multiple customers can have multiple virtual machines all built on top of the same hypervisor, while providing isolation between the customers?

Answer 15

Multi-tenancy environments allow isolation between groups users (e.g. customers in a cloud provider’s network), while allowing each group of users to construct multiple virtual machines on the same underlying hypervisor.

Question 16

Which of the following protocols takes advantage of a virtual IP address?

Answer 16

A virtual IP address is an address assigned to an application that doesn’t physically exist. Some devices that leverage a Virtual IP address are load balancers and First Hop Redundancy protocols (FHRPs), such as HSRP and VRRP. STP (Spanning Tree Protocol) is a layer 2 loop prevention protocol used by switches.

Question 17

Which type of network is used in an environment where high-speed access to storage devices is important, such as data centers?

Answer 17

A SAN (Storage Area Network) is a network where there is access to high-speed block storage, seen in places such as Data Centers. With a SAN, the storage appears as if it were directly connected to a host.

Question 18

Private Direct connection

Answer 18

–> private dedicated connection to the cloud network, supports multiple vpcs (redundancy)

high-speed, low-latency connection that allows you to access public and private Cloud services from your local (on-premises) infrastructure.

The connection is enabled via dedicated lines and bypasses the public Internet to help reduce network unpredictability and congestion. More secure, better performance

AWS direct connect gateway // azure private link