Authorized reprint by author zhushigeng (Vinsoney)
Solution 1: MSTP
MSTP is generally used to eliminate loops on Layer 2 switching networks. A spanning tree protocol, usually MSTP, is run on the core switches SW1 and SW2, and the two switch cards of an Advanced Telecommunications Application Environment (ATAE) frame. MSTP needs to be configured to ensure that the port connecting two switch cards of an ATAE frame is blocked by MSTP in the partial-ring Layer 2 network. This solution requires more data configuration and maintenance on each device compared with solution 2 and solution 3. In actual projects, MSTP is still feasible for loop prevention if there are a large number of devices, for example, more than 10 devices. Network topologies are changed and the topology redundancy is ensured by exchanging STP BPDUs. The following figure describes how MSTP works in this example.
Solution 2: Stacking
The stacking solution is more recommended for eliminating loops, but it is required that devices support the stacking feature. The stacking technology combines multiple physical devices into a single logical device. For example, two independent core switches can form a logical device, which is equivalent to a standalone switch. In addition, ATAE3.0 supports stacking of switch cards. In this solution, two core switches are stacked and two switch cards of an ATAE frame are stacked as well. In addition, the link aggregation technology is used to bond multiple physical links into a logical link to increase link bandwidth, ensure link redundancy, and eliminate loops, as shown in the following figure:
The following figure describes the detailed process.
