With the Aruba CX 6200 24G switch with uplinks or 1/1/25 and 1/1/26, how do you protect client ports from forming layer-2 loops?

The loop-protect feature in ArubaOS-CX is specifically designed to detect Layer 2 loops on non-STP-aware edge ports, which are typically client-facing ports. It works by sending loop-protect packets and if the switch receives its own packet back on that port, it identifies a loop and disables the port. The question asks to protect client ports, which on the specified 24-port switch are interfaces 1/1/1 through 1/1/24. The loop-guard feature is an STP enhancement intended for inter-switch links (like uplinks) to prevent loops caused by the cessation of BPDU reception, making it unsuitable for client ports where BPDUs are not typically expected.

B. int 1/1/1-1/1/28. loop-protect: The port range is incorrect. The Aruba CX 6200 24G switch has ports up to 1/1/26 (24 access + 2 uplinks), not 1/1/28.
C. int 1/1/1-1/1/28. loop-guard: This option uses the incorrect feature (loop-guard) for client ports and specifies an invalid port range for the switch model.
D. int 1/1/1-1/1/24. loop-guard: While the port range for client ports is correct, loop-guard is the wrong feature. It is designed for STP-enabled, non-designated ports (like uplinks), not client access ports.

1. ArubaOS-CX 10.11 Security Guide

Page 121

"Loop protection" chapter.

"Loop protection provides protection against loops by transmitting loop-protect packets out of ports. If a port receives a loop-protect packet that it sent

it recognizes that a loop has occurred and will shut down the port... Loop protection is best used on non-STP-aware devices and on unmanaged access layer switches." This confirms loop-protect is for edge/client ports.

2. ArubaOS-CX 10.11 Spanning Tree Protocol Guide

Page 41

"Loop Guard" chapter.

"Loop guard is a Spanning Tree Protocol (STP) feature that provides additional protection against Layer 2 forwarding loops... Loop guard should be enabled on non-designated ports

such as root and alternate ports." This clarifies that loop-guard is for STP links between switches

not client ports.

3. ArubaOS-CX 10.11 Command-Line Interface Guide

Page 2299

loop-protect command.

The guide shows the command syntax as loop-protect applied under the interface context (config-if). The example switch(config-if)# loop-protect validates the command used in option A.