Hello fellow network enthusiasts,
I’ve been delving into IPv6 subnetting recently and stumbled upon a challenge that’s been giving me a bit of trouble. I was hoping to seek some insights and solutions from this knowledgeable community.
Here’s the scenario:
I have been allocated the IPv6 block 2001:0DB8:ACAD::/48 for my organization. Within this block, I need to subnet it to accommodate the following requirements:
- One subnet for the headquarters with at least 2000 host addresses.
- Three regional offices, each requiring at least 1000 host addresses.
- Ten branch offices, each requiring at least 500 host addresses.
- Future expansion considerations for additional offices.
Could anyone provide guidance on how best to subnet this IPv6 block to meet these requirements efficiently while ensuring room for future growth? Any detailed explanations or step-by-step approaches would be greatly appreciated.
Thank you in advance for your help!
2 Likes
Host addresses aren’t an issue. You’ll use a /64 for all regular LANs. Instead, look at how you might want or need to change the overall distribution of LANs over time. The RIPE NCC has a section on building addressing plans in its IPv6 Fundamentals course.
2 Likes
Hello,
As Leo mentioned the host count is not important. The number of subnets is the one to take into account.
I can share a draft idea to help you further with your planning. First you can split your allocation into 16 by having a /52 on each part. And you can use 4 of these /52s for your HQ and regional offices.
When it comes to the branch office networks, you can divide /52s into 16 again and use a /56 for each of these branches (according to the region they are in).
To make it more clear;
| 2001:db8:acad::/52 |
Head Quarter |
| 2001:db8:acad:1000::/52 |
Regional Office 1 |
| 2001:db8:acad:2000::/52 |
Regional Office 2 |
| 2001:db8:acad:3000::/52 |
Regional Office 3 |
| 2001:db8:acad:4000::/52 |
Future Reserve |
| 2001:db8:acad:5000::/52 |
Future Reserve |
| 2001:db8:acad:6000::/52 |
Future Reserve |
| 2001:db8:acad:7000::/52 |
Future Reserve |
| 2001:db8:acad:8000::/52 |
Future Reserve |
| 2001:db8:acad:9000::/52 |
Future Reserve |
| 2001:db8:acad:a000::/52 |
Future Reserve |
| 2001:db8:acad:b000::/52 |
Future Reserve |
| 2001:db8:acad:c000::/52 |
Future Reserve |
| 2001:db8:acad:d000::/52 |
Future Reserve |
| 2001:db8:acad:e000::/52 |
Future Reserve |
| 2001:db8:acad:f000::/52 |
Future Reserve |
I hope it helps.
1 Like
Thank you for your response and suggested subnetting plan. Your draft idea provides a clear structure for allocating IPv6 subnets to accommodate the specified requirements.
To ensure I understand correctly, each of the regional offices would be allocated a /52 subnet, and the branch offices within each region would then be further subnetted using /56 subnets, correct?
Your breakdown of the IPv6 block into 16 /52 subnets allows for efficient allocation of resources while leaving room for future expansion, which is greatly appreciated.
I’ll proceed with implementing this subnetting plan and let you know if I encounter any further questions or challenges. Thank you once again for your assistance! 
Yes, that’s correct!
You can use the first /52 for your HQ and use the others for the regions. Then for the branch offices, you can use /56s in those /52s.