Cloud Networking Overview (Using AWS as reference)

Summary

This video script delves into the relevance of network administration in cloud environments, emphasizing the necessity of configuring and managing network services post-cloud migration. It explores AWS networking fundamentals, such as VPCs, CIDR blocks, subnets, and internet gateways, highlighting security best practices. The script also touches on advanced topics like VPC peering, hub and spoke architectures, and transit gateways for inter-VPC communication. It concludes by introducing Cisco's ACI for cloud, which simplifies network configuration across multiple clouds, promising a unified operational model and consistent security policies.

Takeaways

• 🌐 **Cloud Networking Importance**: Network admins and networking knowledge remain crucial in the cloud for configuring and managing network services.
• 🛠️ **Cloud Networking Services**: Services like AWS VPC require configuration and management, emphasizing the need for network expertise in cloud environments.
• 🔄 **Avoid Default VPC**: AWS recommends against using the default VPC due to its non-compliance with security best practices.
• 🏗️ **VPC Configuration**: Creating a VPC involves setting up CIDR blocks, subnets, and internet gateways to establish a foundational network structure.
• 🌐 **Region-Specific Networking**: Networking configurations in the cloud are region-specific, necessitating separate configurations for different regions for geographical redundancy.
• 🔒 **Security by Design**: Cloud providers embed security policies that require explicit access grants, similar to Cisco ACI's policy model.
• 🚦 **Routing and Subnets**: Proper routing table configuration and subnet management are essential for controlling traffic flow within a VPC.
• 🔌 **ENI and Network Adapters**: Elastic Network Interfaces (ENIs) and other network adapters like ENAs and EFAs play a key role in providing connectivity with varying performance characteristics.
• 🌐 **Hybrid and Multi-Cloud Connectivity**: Techniques like VPC peering, hub and spoke architectures, and transit gateways facilitate communication across multiple VPCs and clouds.
• 🔄 **Cloud ACI Benefits**: Cisco ACI in the cloud simplifies network operations by abstracting configurations and automating enforcement across different cloud environments.

Q & A

Why are network admins and networking knowledge still important in the cloud era?

Network admins and networking knowledge are crucial because multiple network services need to be configured and managed in the cloud. Network admins with existing knowledge can be valuable assets in an organization's cloud migration strategy.

What is the first step in setting up cloud networking without using ACI?

The first step is to create a Virtual Private Cloud (VPC), which is similar to a VRF in traditional networking. It is recommended to create a custom VPC instead of using the default one to ensure it meets security best practices.

Why should you avoid using the default VPC in AWS?

The default VPC comes with a default configuration that may not meet security best practices, which is why AWS recommends creating a custom VPC for better security control.

What is a CIDR block and why is it necessary in cloud networking?

A CIDR block is a main IP address block from which subnets can be created. It is necessary to define the network range for instances or VMs within a VPC.

How does internet connectivity work for a VPC in AWS?

Internet connectivity for a VPC is provided by an Internet Gateway (IGW), which must be created and attached to the VPC.

What are the differences between private and public subnets in AWS?

Private subnets do not have direct internet connectivity, while public subnets may have internet-facing connectivity using a public or elastic IP address.

How does AWS handle IP address assignment for instances in private subnets?

AWS automatically assigns private IP addresses to instances in private subnets, reserving the first three usable IP addresses per subnet.

What is the purpose of a routing table in AWS VPCs?

A routing table in AWS VPCs determines the path for network traffic to and from instances. It includes routes that control the subnets' internet access and connectivity between instances.

What are the two main ways to achieve network segmentation and define policy in AWS?

The two main ways to achieve network segmentation and define policy in AWS are Security Groups and Network Access Control Lists (ACLs).

How do Security Groups in AWS compare to ACI EPGs?

Security Groups in AWS are comparable to ACI EPGs as they control inbound and outbound traffic and are assigned per instance, following an allow list model.

What is the significance of Cloud ACI in managing multi-cloud environments?

Cloud ACI abstracts the network configuration and automatically creates corresponding configurations across clouds, unifying operational models and maintaining security consistency, which simplifies management in multi-cloud environments.