CIDR Notation for VPCs with IPv6 Addresses | AWS Certified Advanced Networking - Specialty

Which CIDR Notation Mask is Assigned to a VPC with IPv6 IP Addresses?

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Question

Which of the below CIDR notation mask is assigned to a VPC which holds IPv6 IP addresses?

Answers

Explanations

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A. B. C. D.

Answer - C.

For IPv6, the VPC is a fixed size of /56 (in CIDR notation)

A VPC can have both IPv4 and IPv6 CIDR blocks associated to it.

For more information on the VPC , please refer to the below URL:

https://aws.amazon.com/vpc/faqs/
Q. How large of a VPC can | create?

Currently, Amazon VPC supports five (5) IP address ranges, ane (1) primary and four (4) secondary for IPv4. Fach of these
ranges can be between /28 (in CIDR notation) and /16 in size. The IP address ranges of your VPC should not overlap with
the IP address ranges of your existing network.

For IPv6, the VPC is a fixed size of /56 (in CIDR notation). A VPC can have both IPv4 and IPv6 CIDR blocks associated to it.

When a VPC is created, it can be assigned an IPv4 CIDR block and/or an IPv6 CIDR block.

IPv6 addresses use a 128-bit address space, which is significantly larger than the 32-bit address space used by IPv4. This allows for an almost unlimited number of unique addresses, making it possible to assign a unique address to every device on the planet and then some.

IPv6 addresses are usually assigned using a /64 prefix. A /64 prefix is the smallest block of IPv6 addresses that can be assigned to a network. It contains 2^64 unique addresses, which is enough to assign a unique address to every device on the network.

Therefore, the answer to the question is D. /64. A /64 prefix is assigned to a VPC which holds IPv6 IP addresses. It is the smallest block of IPv6 addresses that can be assigned to a network.

To summarize:

  • IPv4 addresses use a 32-bit address space and are assigned using a prefix in the range of /16 to /28.
  • IPv6 addresses use a 128-bit address space and are assigned using a prefix of /64.