Data Forwarding Mode
Packets transmitted on a WLAN include control packets (management packets) and data packets. Control packets are forwarded through CAPWAP control tunnels. Data packets are forwarded through tunnel forwarding (centralized forwarding) or direct forwarding (local forwarding) according to whether data packets are forwarded through CAPWAP data tunnels.
Tunnel Forwarding
Direct Forwarding
Comparison Between Tunnel Forwarding and Direct Forwarding
| Data Forwarding Mode | Advantage | Disadvantage |
|---|---|---|
| Tunnel forwarding | An AC forwards all data packets, ensuring security and facilitating centralized management and control. |
Service data must be forwarded by an AC, reducing packet forwarding efficiency and burdening the AC. |
| Direct forwarding | Service data does not need to be forwarded by an AC, improving packet forwarding efficiency and reducing the burden on the AC. |
Service data is difficult to manage and control in a centralized manner. |
Centralized Authentication in Direct Forwarding Mode
If direct forwarding is used, service data does not need to be forwarded by an AC. When user access authentication (for example, 802.1X authentication) is required on a wireless user access network and the access control point is deployed on an AC, user authentication packets cannot be managed by the AC in a centralized manner. This makes in controlling users in a uniform manner difficult.
Centralized authentication can be enabled in direct forwarding mode so that user authentication packets can be forwarded over CAPWAP tunnels to the AC, while common data packets do not need to be forwarded by the AC. Figure 4-18 shows a network using centralized authentication in direct forwarding mode.
