A-loop Protection

Security, Reliability, Simplicity, Performance.

The A-Loop Module detects loops in a MSTNT network using a unique Linux kernel implementation of both passive and active loop detection methods. The A-Loop Module uses a Linux kernel module for its (core) Layer 2 ebtables firewall. This assures significantly improved performance. In the passive method, A-Loop uses multicast and broadcast packet counters received. When a set limit is exceeded; that is, when the loop has already gained a certain strength (packet flow), a loop is detected. In the active loop detection method, A-Loop transmits a special Ethernet packet of a certain type every N seconds (N is set to 5 seconds by default) and analyzes response characteristics.

  • An A-loop software package (kernel module and userspace process) that runs on a subscriber device that analyzes network traffic transmitted from the LAN ports of the client network to the MSTP tunnel to detect and block loops appearing in the network.
  • Built-in effective loop removal with real-time analysis of network traffic transmitted from LAN ports to the tunnel to detect and block loops that appear on the network without disconnecting the network segment of the affected loop.
  • This logs the time when the network loop appears and disappears.