Subnet-Calculator.Pro
Network IP Planner
Step 1: Define Sites / Branches & Subnets
List each site, then add the specific subnets (VLANs) required within each.
Step 2: Define Main Network Block
Based on your needs, we can suggest an optimal block, or you can enter your own.
Total Requirements Summary
Total Hosts Required: 0
Suggested Main Block: N/A
Step 3: Allocation Strategy
Choose how to assign blocks to your sites for easier management or maximum efficiency.
A Guide to Hierarchical IP Address Planning for Enterprise Networks
Design a scalable and organized IP addressing scheme for your entire organization with our advanced Network IP Planner. This tool moves beyond single-site subnetting, allowing you to model a complete, multi-site enterprise network. Define your headquarters, branch offices, and data centers, specify the VLANs and host counts for each, and let the planner automatically generate a logical, hierarchical, and efficient IP plan. This is an essential tool for network architects, CCNP/CCIE candidates, and anyone tasked with designing a robust enterprise network.
About the Network IP Planner
The Network IP Planner is a professional tool designed for creating structured, hierarchical IP addressing schemas, following industry best practices taught in certifications like CCNA, CCNP, and CCIE. It facilitates a top-down approach to network design. You start by defining your organization's total address space, then segment it into logical summary blocks for each site or branch. Finally, the tool breaks down each site's block into smaller subnets to meet the specific host requirements of different functions (e.g., user VLANs, servers, voice). You can choose between a "Clean Cut" allocation for ease of management and a fully "Optimized" VLSM allocation for maximum address efficiency.
How to Design Your Network Plan
This planner guides you through a logical workflow that mirrors a real-world network design process.
Step-by-Step Design Guide
- Define Your Sites: Click the "Add Site / Branch" button for each major location in your network (e.g., "Headquarters," "London Office," "Data Center"). Give each site a descriptive name.
- Define Subnets within Each Site: Inside each site card, click "Add Subnet / VLAN" for every required network segment. Name each subnet (e.g., "Staff VLAN," "Servers," "Guest Wi-Fi") and enter the number of hosts (devices) it needs to support. Plan for future growth by adding a buffer (e.g., 25-50% more hosts than you currently need).
- Determine Your Main Network Block: As you add requirements, the "Total Requirements Summary" will update. The tool will suggest an optimal parent CIDR block for your entire enterprise. You can click the "Suggest & Use Optimal Block" button to populate this, or if you've been assigned a specific IP block, you can enter it manually (e.g.,
10.10.0.0/16). - Choose an Allocation Strategy:
- Clean Cut (Recommended for most): This strategy allocates easy-to-remember supernet blocks to each site (e.g., a /22 or /23 block). This greatly simplifies writing firewall rules and configuring route summarization between sites.
- Optimized: This strategy uses pure VLSM to assign the smallest possible supernet block to each site, conserving the maximum number of IP addresses. This is useful when IP space is extremely limited.
- Generate and Review: Click "Generate Network Plan." The tool will display a detailed, multi-level plan showing the summarized block assigned to each site, followed by a table of the individual subnets allocated within that site. You can click on any subnet name to see a detailed breakdown.
The Principles of Hierarchical Network Design
A flat network, where all devices are in one large address space, is not scalable or secure. Hierarchical design imposes a logical structure on the network, which is essential for growth and manageability.
The Core-Distribution-Access Model
This is a classic three-layer hierarchical model used in enterprise LAN design:
- Access Layer: Where end-user devices (computers, phones, printers) connect to the network, typically via access switches. VLANs and subnets are implemented here to segment traffic.
- Distribution Layer: Aggregates traffic from the access layer. This is where routing between VLANs (inter-VLAN routing), and policy enforcement (ACLs) are typically applied.
- Core Layer: The high-speed backbone of the network, responsible for fast and reliable transport between distribution layer devices and other core components (like data center connections or the internet edge).
The Importance of Summarization
A key goal of hierarchical IP planning is to enable route summarization. By allocating a contiguous block of IP addresses (a supernet) to an entire site, the router for that site can advertise just one single route to the rest of the enterprise. This has several major benefits:
- Smaller Routing Tables: Routers across the enterprise have fewer routes to process, which reduces CPU load and memory usage.
- Increased Stability: If a single subnet within a site goes up or down, the change is contained within that site. The summary route advertised to the rest of the network remains stable, preventing unnecessary routing protocol updates across the WAN.
- Simplified Troubleshooting: A logical, summarized IP plan is much easier to read and troubleshoot than a flat, disorganized one.
This Network IP Planner is a powerful tool for modeling and visualizing an enterprise IP addressing scheme. For a production environment, this plan would be the foundation for configuring routing protocols (like OSPF or EIGRP), security policies on firewalls, and Quality of Service (QoS) for real-time traffic. Always consult with a certified network architect or engineer to translate your IP plan into a fully functional and secure network design.
Frequently Asked Questions about IP Planning
What is a Network IP Planner?
A Network IP Planner is a tool that helps network architects and engineers design a structured and efficient IP addressing scheme, especially for large or multi-site networks. It automates the process of subnetting a large address block to meet the specific host requirements of various departments, sites, and services.
Why is hierarchical network planning important?
Hierarchical network planning is crucial for scalability, manageability, and efficient routing. It allows for effective route summarization, which reduces the size of routing tables and improves network stability. It also creates a logical, organized structure that is easier to troubleshoot and secure.
How do I use this Network IP Planner?
First, add each of your sites (e.g., 'Headquarters', 'Branch Office'). Within each site, add the required subnets (e.g., 'Users', 'Servers') and the number of hosts for each. Then, enter your main network block (or use our suggestion) and choose an allocation strategy. Finally, click 'Generate Network Plan' to see the full, detailed IP scheme.
What is the difference between 'Clean Cut' and 'Optimized' strategies?
'Clean Cut' allocates subnets on easy-to-remember boundaries (like /24, /23), which simplifies firewall rules and management. 'Optimized' uses classic VLSM to assign the smallest possible block that meets the host requirement, maximizing IP address conservation.
How does the tool suggest an 'Optimal Block'?
The tool calculates the total number of IP addresses required for all your defined sites and subnets, factoring in the chosen allocation strategy. It then determines the smallest standard CIDR block (e.g., /22, /16) that can accommodate this total and suggests a private IP range for that block.
What is VLSM?
VLSM (Variable Length Subnet Masking) is a technique for dividing an IP address space into subnets of different sizes. This allows you to allocate addresses very efficiently, matching the size of the subnet to the actual number of hosts required. Our dedicated VLSM Calculator focuses on this for single-site planning.
How is this tool different from a VLSM calculator?
A VLSM calculator is perfect for planning subnets within a single location. This Network IP Planner takes it a step further, designed for multi-site, hierarchical planning. It first allocates a summarized block to each site and then performs subnetting within that site block, mimicking a real-world enterprise design process.
What is route summarization?
Route summarization (or route aggregation) is the process of combining multiple smaller network routes into a single, larger route advertisement. A well-planned hierarchical network allows a router to advertise one summary route (e.g., 10.1.0.0/16 for the entire Branch Office) instead of dozens of smaller routes, which improves routing performance. Our Supernet Calculator can help calculate these summaries.
What is a VLAN?
A VLAN (Virtual LAN) is a logical grouping of devices on a network that are configured to communicate as if they were attached to the same wire, regardless of their physical location. Each VLAN is a separate broadcast domain, and in network planning, each VLAN is typically assigned its own unique IP subnet.
How many hosts should I plan for?
When entering host requirements, you should account for every device that needs an IP address: computers, printers, phones, servers, cameras, etc. It is always a best practice to add a buffer for future growth (e.g., plan for 25-50% more hosts than you currently need).
Why does the tool add 2 to my host count?
In every IPv4 subnet, two addresses are reserved: one for the Network ID and one for the Broadcast Address. The tool automatically adds 2 to your host requirement to ensure the allocated subnet has enough addresses for your devices *plus* these two reserved addresses.
What is a typical IP plan for a small office?
A typical small office might use a single /24 block (e.g., 192.168.1.0/24). For better security and management, this is often segmented into VLANs/subnets, such as a /26 for staff computers, a /27 for servers, and another /26 for guest Wi-Fi.
What is a private IP address (RFC 1918)?
Private IP addresses are blocks (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) reserved for use in internal networks. They are not routable on the public internet. This planner is designed to work with these private address ranges.
How do different sites communicate with each other?
Different sites in an enterprise network are typically connected via a Wide Area Network (WAN). Communication between the IP subnets at different sites is handled by routers, often over secure connections like VPN tunnels or dedicated MPLS links.
Can I save my network plan?
Yes. After generating a plan, a 'Save Plan' button will appear. This allows you to save your entire configuration (main block, sites, and subnets) in your browser's local storage for future reference or modification.
Are my network plans sent to your server?
No. All calculations and plan storage are performed client-side, directly in your web browser. The details of your network design are never transmitted to our servers, ensuring your privacy and confidentiality.
What is a /24 subnet?
A /24 subnet is a block of 256 IP addresses, with 254 of them being usable for hosts. It is the most common subnet size for a standard LAN segment. The mask is 255.255.255.0. You can explore this with our CIDR Calculator.
Why is the plan sorted by the largest site first?
The tool allocates IP blocks by first satisfying the needs of the largest sites. This is a best practice in VLSM and hierarchical design that ensures large, contiguous blocks are available for the sites that need them most, preventing the address space from being fragmented by smaller allocations.
What is the 'round up to /24' option for?
This option, available with the 'Clean Cut' strategy, enforces a policy where every individual subnet (like a VLAN) is at least a /24 in size, even if it requires fewer hosts. This is a form of Fixed Length Subnet Masking (FLSM) that simplifies management at the cost of using more addresses.
Can I print my network plan?
Yes. Once a plan is generated, a 'Print / Save as PDF' button will appear in the results section, allowing you to create a document of the complete, detailed IP allocation plan for your records.
What does the 'Subnet Detail Modal' show?
Clicking on a subnet name in the results table opens a modal window with a detailed breakdown of that specific subnet, including its size, usable hosts, subnet mask, wildcard mask, host range, and broadcast address.
What is a 'default gateway'?
A default gateway is the IP address of the router interface that devices on a subnet use to send traffic to other networks. Typically, this is the first usable IP address in the subnet's host range.
How many sites can I add?
You can add as many sites and subnets as you need to model your network. The tool is designed to handle complex, multi-site enterprise scenarios.
Does this tool work for IPv6?
This planner is specifically designed for IPv4 hierarchical planning. IPv6 planning follows different principles, typically assigning /64 subnets for every LAN. You can use our IPv6 Calculator to work with IPv6 addresses.
Do I need a network professional to create an IP plan?
While this tool is powerful for modeling and learning, designing an IP plan for a production business network is a critical task. A professional network engineer or architect should be involved to ensure the plan accounts for routing protocols, security segmentation, scalability, and high availability requirements.