IPv6 subnetting confusion

[Linux911S]

I'm a newcomer to this fantastic Cisco community, and yes i'm a "Rookie."

I'm currently studiying for the CCNA and have tried exploring what I can learn through freely available resources, 

I'm currently trying to learn IPv6 concepts.

Although I'm aware that the CCNA doesn't demand an exhaustive understanding of IPv6, I'm determined to grasp the concept to a certain depth, particularly when it comes to understanding subnetting thoroughly.

I've made attempts to learn IPv6 subnetting through various means, including consulting chatGPT and other resources. However, I've found the subject somewhat confusing, mainly due to conflicting information and a lack of comprehensive explanations.

I kindly request Ya'll to share your IPv6 subnetting knowledge in a step-by-step format, with a strong emphasis on detailed explanations. To illustrate my specific areas of confusion, I've listed some confusions below, some of which I've previously asked chatGPT:

1. Could someone explain what determines whether the "n" subnetting bits should be set as 0s or 1s in binary when they are added to the new prefix for an IPv6 address? For instance, if I have 3 subnetting bits, what should these 3 bits appear as in binary when combined with a nibble for the new prefix? Should they be represented as 1110 in binary, thereby converting the nibble containing the subnet ID to 14, or should they be 0000, resulting in the subnet ID becoming 0?

2. What factors influence the IPv6 incrementation pattern?

3. Regarding the statement that "the networks will go in increments of 16 (constant) - 14 (the subnet nibble) = 2 in the interesting nibble," I'm curious about the significance of the constant value 16. Additionally, what happens if the subnet nibble exceeds this constant value? and I don't really understand it overall

I would greatly appreciate it if someone could subnet IPv6 problems while emphasizing these perplexing aspects. As an example,  IPv6 address 2001:233F:335D:355A::/64 into 8 subnets.

[David Ruess]

Hello,

A couple things to help you understand the concept a little bit better. For one, I personally would not recommend using ChatGPT or any other generative AI to learn a subject especially for the very first time. As its only as good as what its being asked of and if you dont understand the topic to begin with then you can see the massive void you fall into. If you use an untrusted technology against vetted sources that have been out for almost decades then you run the risk of missing key information and ultimately not understanding the topic at all as you mentioned. I would say you don't subnet IPv6 addresses in the traditional IPv4 sense as the reason we subnetted IPv4 addresses is to eliminate wasted address space. IPv6 doesn't have that problem.

Here are a couple of recourses that may be able to help you:

https://subnettingpractice.com/how-to-subnet-ipv6.html

https://ipcisco.com/lesson/subnetting-in-ipv6/

Cisco Press also has a book that I have and its done wonders for my understanding:

https://www.ciscopress.com/store/ipv6-fundamentals-a-straightforward-approach-to-understanding-9781587144776

While this is well and above CCNA knowledge.

For CCNA the blueprint lists this as what you need to know when it comes to IPv6:

• 1.8 Configure and verify IPv6 addressing and prefix

• 1.9 Describe IPv6 address types
  • 1.9.a Unicast (global, unique local, and link local)
  • 1.9.b Anycast
  • 1.9.c Multicast
  • 1.9.d Modified EUI 64 

Hope that helps

-David

[Linux911S]

Thanks David,

Highly appreciate your input and yes you're right about chatGPT... I've viewed these free resources before and it often happens that you miss the key points and it clicks by reviewing multiple times so thanks for those and by the way can you share your experience with using books prior to taking certs? And do you guys recommend any more communities on social platforms where we could share study notes related to these topics?

[David Ruess]

No problem.

I find here is good for more complex and intricate issues and problems. Not so say here isn't good for any network problem but some places like Discord (which I use) to get answers quicker and to be able to bounce ideas off other people and have a more streamlined conversation about a topic you're struggling with. I enjoy books as I can highlight and tab things I want to lab. 

Another resource that may be able to help you with subnetting IPv6 addresses. 

https://subnettingpractice.com/ipv6-subnetting-practice.html

-David