Networking Flashcards
Networking has 2 types of IPs. Name them
IPv4 and IPv6
IPv4 is still the most common format used online
IPv4 allows for 3.7 billion different addresses in the public space
IPv4: [0-255].[0-255].[0-255].[0-255]
IPV6 is newer and solves problems for IoT devices
What is a placement group?
A placement group in AWS is a logical grouping of instances within the same Availability Zone to achieve specific performance or architectural goals.
What are the types of placement groups?
Cluster, Spread, and Partition
What is a Cluster placement group?
This type is designed for applications that benefit from low network latency, high network throughput, or both. Instances within a cluster placement group are placed in close physical proximity to each other, within a single Availability Zone.
What is a Spread placement group?
In this type, instances are spread across distinct underlying hardware to reduce the risk of simultaneous failure. It’s suitable for applications that have a small number of critical instances that must be kept separate.
What is a Partition placement group?
This type enables you to spread instances across partitions to ensure that each partition maintains its performance attributes while benefiting from the aggregate network bandwidth and aggregate IOPS available to the group.
What is an ENI?
Elastic Network Interfaces
It is a logical component in a VPC that represents a virtual network card
What are the important attributes of an ENI?
Primary private IPv4, one or more secondary IPv4
One Elastic IP (IPv4) per private IPv4
One Public IPv4
One or more security groups
A MAC address
ENI can be created independently and attach them on the fly on EC2 instances for failover. True or False?
True
ENI can be bound to multiple AZs. True or False?
False
ENI can be bound to a specific availability zone
What happens to public IP address when you restart a running EC2 instance?
A new public IPv4 address is allocated to the EC2 instance after restart
You are using ssh to login to the EC2 instance using the security key. A little while later, you restart the instance after which you are no longer able to connect to the EC2 instance. Why? and how do you fix the issue?
After a restart you are unable to ssh to the EC2 instance because a new public IPv4 address is allocated which prevents you from connecting. The solution is to create an Elastic IP. It is not free and you get charged
You have launched an EC2 instance that will host a NodeJS application. After installing all the required software and configured your application, you noted down the EC2 instance public IPv4 so you can access it. Then, you stopped and then started your EC2 instance to complete the application configuration. After restart, you can’t access the EC2 instance, and you found that the EC2 instance public IPv4 has been changed. What should you do to assign a fixed public IPv4 to your EC2 instance?
Allocate an Elastic IP and assign it to your EC2 Instance
Spot Fleet is a set of Spot Instances and optionally
a) Reserved Instances
b) On-Demand Instances
c) Dedicated Hosts
d) Dedicated Instances
b) On-Demand Instances
You have an application performing big data analysis hosted on a fleet of EC2 instances. You want to ensure your EC2 instances have the highest networking performance while communicating with each other. Which EC2 Placement Group should you choose?
Cluster Placement Groups place your EC2 instances next to each other which gives you high-performance computing and networking.
