Technical information

AX Series L2 Loop Detection Configuration Guide (Edition 2)

1.4 L2 loop detection functionality

(1) Functionality overview

The L2 loop detection functionality is used to detect a loop failure in a Layer 2 network and correct the loop

failure by blocking the port that caused the loop. The L2 loop detection functionality can be used not only for core

networks made redundant with an L2 redundancy protocol, such as the spanning tree protocol and Ring Protocol,

but can also be used for access networks that cannot use such redundancy protocols.

Figure 1.4-1 Basic patterns of loop failures

The L2 loop detection functionality can prevent the above-mentioned patterns (1 to 4) of loop failures.

Pattern 1

An invalid connection on this

device causes a loop failure.

Core network

Patterns 2 and 3

An invalid connection on the Switch

or an L2 switch under the device

causes a loop failure.

Preventin

loo

failures via s

annin

trees

etc.

Switch

Switch C

Switch E

ccess network

The L2 loop detection functionality can

prevent loop failures.

Pattern 4

An invalid connection on a

device under the Switch

causes a loop failure across

the core network.

Switch B

Switch D

(Legend) ----: Improperly connected

line

: Loop flow

: Blocked status