1.2 Describe wireless network design principles
📘CCNP security (350-701)
Wireless Deployment Models
Wireless networks can be deployed in different ways depending on the size, complexity, and requirements of the organization. Understanding these models is crucial for designing a secure and efficient wireless network. There are six main deployment models:
- Centralized
- Distributed
- Controller-less (Autonomous)
- Controller-based (Lightweight)
- Cloud-managed
- Remote branch deployments
We’ll go through each one in detail.
1. Centralized Wireless Deployment
Definition:
In a centralized deployment, all wireless access points (APs) are connected to a central controller. This controller manages configuration, security, and policies for all APs.
Key Features:
- APs are “dumb” devices; they rely on the controller for intelligence.
- Security, authentication, and firmware updates are handled centrally.
- Easy to manage multiple APs from a single location.
Example in IT environment:
A corporate office with hundreds of employees might use a centralized model with all APs connected to a controller in the server room. The IT team can push security updates to all APs at once.
Pros:
- Centralized management simplifies administration.
- Easier to enforce network-wide security policies.
- Simplifies troubleshooting because the controller logs events from all APs.
Cons:
- Single point of failure: if the controller goes down, APs might lose functionality.
- Higher upfront cost for the controller.
2. Distributed Wireless Deployment
Definition:
In distributed deployment, each AP operates independently and manages its own configuration and security. There’s no central controller.
Key Features:
- APs are standalone devices with built-in intelligence.
- Suitable for smaller networks or locations where a central controller isn’t practical.
Example in IT environment:
A small branch office with only a few APs where each AP is configured individually.
Pros:
- No single point of failure.
- Flexible deployment in small or remote locations.
Cons:
- Harder to manage multiple APs.
- Configuration changes must be made on each AP separately.
- Security policies may vary across APs, which can be risky.
3. Controller-less (Autonomous) Wireless Deployment
Definition:
Controller-less APs are also known as autonomous APs. They don’t need a central controller and handle all functions by themselves, including security, routing, and management.
Key Features:
- Each AP functions independently.
- Configuration, firmware updates, and monitoring are done on the AP itself.
Example in IT environment:
A retail store with 3-5 APs. Each AP is configured manually for security and SSID.
Pros:
- Lower initial cost (no controller needed).
- Suitable for small offices or shops.
Cons:
- Not scalable for large networks.
- Manual updates can be time-consuming.
4. Controller-based (Lightweight) Wireless Deployment
Definition:
Controller-based or lightweight APs rely on a wireless LAN controller (WLC) for most of their functionality. The APs only handle radio transmission and basic networking, while the controller does the heavy lifting.
Key Features:
- Centralized management via WLC.
- Lightweight APs forward all management traffic to the controller.
- Controller handles authentication, encryption, roaming, and policy enforcement.
Example in IT environment:
A university campus with hundreds of APs where students roam between buildings. The controller ensures smooth handoff and consistent security policies.
Pros:
- Highly scalable for large networks.
- Easy policy enforcement and monitoring.
- Simplifies firmware updates.
Cons:
- If the controller fails, APs may continue limited operation but with reduced functionality.
- Higher cost due to controller and infrastructure.
5. Cloud-managed Wireless Deployment
Definition:
Cloud-managed deployments use APs managed through a cloud-based platform. The controller is effectively in the cloud, not on-premises.
Key Features:
- APs connect to the cloud controller via the internet.
- IT admins can configure, monitor, and update APs from anywhere.
- Often integrates with analytics, AI, and network monitoring tools.
Example in IT environment:
A company with multiple branches in different cities uses cloud-managed APs. IT administrators manage all APs from a single dashboard in the cloud.
Pros:
- Centralized management without a local controller.
- Easy to scale across multiple locations.
- Real-time monitoring and analytics.
Cons:
- Internet dependency for management (but APs may continue working locally if connection drops).
- Ongoing subscription costs for cloud management.
6. Remote Branch Wireless Deployment
Definition:
Remote branch deployments are designed for smaller or remote offices. These can be a mix of controller-less or cloud-managed deployments.
Key Features:
- Often use VPNs to connect to headquarters.
- Management can be centralized (via cloud) or local (controller-less).
Example in IT environment:
A branch office in another city connects its APs to the main office via a VPN. Security policies may be pushed from the central office.
Pros:
- Cost-effective for small or remote sites.
- Can leverage cloud or local controllers for management.
Cons:
- May have reduced feature set compared to main office.
- Internet reliability is important for cloud-managed branches.
Summary Table: Wireless Deployment Models
| Model | Controller | Pros | Cons | Best Use Case |
|---|---|---|---|---|
| Centralized | Yes, on-prem | Easy management, strong security | Single point of failure, expensive | Large offices/campuses |
| Distributed | No | No single point of failure | Hard to manage multiple APs | Small offices |
| Controller-less / Autonomous | No | Low cost, simple | Not scalable | Small branch or retail |
| Controller-based / Lightweight | Yes | Scalable, easy policy enforcement | Controller dependency | Campus, large enterprise |
| Cloud-managed | Cloud | Manage from anywhere, scalable | Internet dependency, subscription cost | Multi-branch or distributed orgs |
| Remote branch | Optional | Cost-effective, flexible | Limited features, relies on connectivity | Remote offices |
Exam Tips:
- Know difference between centralized, distributed, controller-less, controller-based, and cloud-managed.
- Remember that centralized vs. distributed is about where intelligence resides.
- Controller-based vs. controller-less is about whether the AP relies on a WLC.
- Cloud-managed is about managing from the cloud instead of on-premises.
- Remote branch deployments are often hybrid.
