STP Scenarios Supported by a Mesh Network
A Mesh network supports only transparent transmission of Spanning Tree Protocol (STP) packets. An STP-enabled AP does not forward STP packets to the wireless side. STP takes effect only on the AP's wired side.
When deploying a Mesh network, avoid network loops. In Mesh networking, STP applies only to scenarios where the Mesh network forms a single loop with the wired network. The Mesh network supports the following two Mesh scenarios:
- Mesh links form a single loop with wired links. STP is enabled on non-AP network elements (NEs) on the loop but not enabled on NEs connected to the Mesh network that are not involved in the loop. In this case, STP takes effect and breaks the loop.Figure 1 Scenario 1
As shown in the Figure 1, the switch forms a single loop with Mesh links. To break the loop, enable STP on the switch and ensure that STP is not enabled on GE0/0/1 connecting the AC to the MPP.
- The Mesh network connects to an AP with dual network ports. A loop exists on the AP's wired-side interfaces and the wired-side interfaces are not bound to an Eth-trunk interface. To prevent transparent forwarding of STA packets to the wireless side, enable STP on the AP.Figure 2 Scenario 2
In the Figure 2, the AC, SwitchA, SwitchB, and MPP form a loop (loop 1), and SwitchC, SwitchD, and MP3 form a loop (loop 2). If STP packets can be transparently transmitted over Mesh links, STP on loop 1 incorrectly includes SwitchC and SwitchD on loop 2 into its calculation.
To prevent calculation errors, enable STP on the MPP and MP3 so that STP packets from loop 1 and loop 2 will not be transparently forwarded to the wireless side. The MPP implements STP calculation of loop 1 and blocks wired-side interfaces based on the calculation results. MP3 implements STP calculation of loop 2 and blocks wired-side interfaces based on the calculation results.
Mesh networks support Mesh link redundancy. To prevent loops, use Mesh routing to decide on the forwarding path.