Distinguishing Fat APs & Fit APs Before Networking

Updated on Feb 27, 2023 by

With a wireless access point (AP), be it at home or in corporate offices, one can easily connect multiple devices for wireless connections with better convenience and higher flexibility. As one of the key parts of building wireless networks, the choice of access points is crucial based on users' various needs. Fat APs and Fit APs with diverse features can meet different networking deployments. This article will make a comparison between these APs for your wiser selection.

Wireless Access Points: Fat vs Fit

Fat AP

The most visible difference between a Fat AP and a Fit AP lies in the WAN port. A Fat AP possesses a WAN port that is easy to tell. In addition, the Fat AP that has both WAN and LAN ports can support security functions such as DHCP server, DNS, MAC address cloning, VPN access, and a firewall. As a network device that can work independently, the Fat AP can implement dialing, routing, and some other functions. Typically, Fat APs are used as stand-alone access points that can operate in the absence of any controller device.

Fat AP

Fit AP

Fit AP, also known as Thin AP, TAP. The "slim version of AP" is intended to reduce the complexity of the hardware of the original APs. Fit AP, without its own complete operating system, removes the routing, DNS, DHCP server, and many other loading functions and only retains the wireless access part. As a component of wireless LAN, Fit AP cannot work independently and requires cooperation with AC management. Actually, Fit APs are quite common in daily use, which is equivalent to a wireless switch or hub, providing only one wired/wireless signal conversion and wireless signal receiving/transmitting function.

Fit AP

Difference Between Fat AP and Fit AP in Networking

The demand for wireless networks in enterprises is steadily rising, which requires powerful wireless devices. Therefore, the number and size of wireless devices are increasing exponentially. Two main solutions for business networking:

Option 1: distributed WLAN networking mode with Fat APs plus wired switches.

Option 2: centralized WLAN management mode with Thin APs plus wireless controllers.

The following part will make an analysis of these two kinds of solutions in five major aspects.

Network Applications for Fat AP vs Fit AP

Since the downsides of Fat APs lie in relative inconvenience, instability, insecurity, and complexity. And Fat APs tend to be built on powerful hardware and require complex software which adds to costs. Fat APs that work independently without AC coordination are normally used in small-sized wireless network constructions like homes and small offices that only cover a small number of users.

While Thin APs with more advantages in WLAN networks. Fit AP/AC installation is easier, it simplifies AP construction with a significant change in costs. But the controller generally needs to be based on a more powerful hardware platform in Fit AP mode due to the higher workload. "AC + AP" mode tends to be the de facto solution for most enterprises nowadays. Besides, Thin/Fit APs can also be applied in medium and large-scale wireless network constructions like shopping malls, supermarkets, hotels, attractions, etc., where multiple APs are combined with AC products to create a larger wireless network coverage.

Wireless Roaming

If the user goes from the coverage area of a Fat AP to the coverage area of another Fat AP, the device will reconnect the new Fat AP with a strong signal, re-authenticate, and re-acquire the IP address. Network disconnection will happen accordingly. However, things will be different if it is a Thin AP. The signal is automatically switched, and there is no need to re-authenticate, and re-acquire the IP address when adopting a Thin AP. That is to say, the signal and the network are always connected online, which may help to avoid the disconnection issue. A Thin AP network can perform seamless roaming across Layer 2 and Layer 3.

Wi-Fi Network Quality and Experience

When many users are connected to the same Fat AP, the Fat AP cannot automatically perform load balancing to allocate users to other Fat APs with lighter loads. Consequently, Fat APs have higher risks of network failures due to heavy load. In the AC + Fit AP configuration, with multiple users connected to the AP simultaneously, the AC will function automatically to allocate users to other APs with lighter loads according to the load balancing algorithm, which minimizes network malfunctions and improves the performance of the entire network.


Most of the simple Fat AP networks only have a single authentication mode with pre-shared keys. Network access security can not be guaranteed, and unified authentication management can not be performed. The Thin AP accepts the management of the wireless controller and is responsible for simple functions such as encryption and decryption of 802.11 messages, with illegal AP detection and processing mechanisms.

O&M Complexity

Fat APs cannot be centrally managed. They need to be configured separately and the configuration work is troublesome. Just imagine that you have a hundred APs in your system. Then every single new AP device needs to be configured one by one. When maintaining, you need to log in to the AP device one by one to view the AP running status and user statistics. For upgrading, you need to upgrade the software manually step by step. Forget about this time-consuming and labor-intensive solution, Fit AP is more intelligent in centralized management. "Fit AP + AC" mode doesn't need a separate configuration. The advantages of this kind of centralized management are outstanding, especially in the case of a large number of APs.

Differences Summary

FAT AP and FIT AP (Thin AP), as two mainstream networking trends in the industry today for enterprise WLAN, the following comparison table will help you better understand the differences between FAP and TAP.

  Fat AP Solution Fit AP Solution
Technology Model Traditional, self-management Emergent new, being managed
Wifi Architecture The management plane, control plane, and data plane are self-managed by the AP. The management plane, control plane, and data plane are managed centrally by AC.
Configuration Configure network and security settings only once Allows remote configuration, no manual configuration, and can change as the network grows
Wireless Roaming User movement is not monitored, L2 roaming Wireless Switch Management, L2, L3 roaming
Safety Personal and enterprise encryption Unified policy management by wireless AC (access point controller), high security
Application Scenario Small-scale networking Large-scale networking

Future Trend: Wireless Access Point Combining Fat & Fit Feature

With the increasing demand for wireless coverage, the performance requirements of wireless APs are also higher and higher. The simple "Fat AP" and "Thin AP" will no longer meet the complex and flexible needs. Between the Fat AP and Fit AP, there is a compromise. Combining the advantages of both fat and Fit APs, the "fat and thin integrated wireless AP" that can switch flexibly between fat & thin modes stands out.

Either deployed as a standalone AP (fat mode) or managed AP (fit mode), the AP will detect the operation mode automatically without extra effort on firmware upgrades. All the user needs is to change the working mode and add ACs for fit mode. This will not only realize a smooth transition with simpler installations but also provide a cost-effective solution. Therefore, this kind of AP solution with a hybrid management model is fit for network upgrading from small-scale to large-scale networks.

At present, these access points that support hybrid management modes are gaining more popularity in enterprise networks. The enterprise-grade APs, most support Wi-Fi 6 standard at present, can not only support flexible switching over the fat and fit modes according to the networking requirements but also meet future development requirements.

You might be interested in

See profile for Sheldon.
Decoding OLT, ONU, ONT, and ODN in PON Network
Mar 14, 2023
See profile for Irving.
What's the Difference? Hub vs Switch vs Router
Dec 17, 2021
See profile for Sheldon.
What Is SFP Port of Gigabit Switch?
Jan 6, 2023
See profile for Migelle.
PoE vs PoE+ vs PoE++ Switch: How to Choose?
May 30, 2024
See profile for Moris.
How Much Do You Know About Power Cord Types?
Sep 29, 2021