Free RUCKUS RCNI Practice Exam with Questions & Answers | Set: 2

The inline power poe-ha command on RUCKUS ICX switches enables two key Power over Ethernet (PoE) features:

Fast Boot PoE: This feature ensures that PoE power is delivered to connected devices immediately upon switch startup, without waiting for the entire system to boot up. This is crucial for devices that need to be operational as soon as possible, such as IP phones or security cameras. To enable Fast Boot PoE, enter interface configuration mode and execute the command:

inline power poe-ha

This command ensures that PoE is delivered promptly during the boot process.

Perpetual PoE: This feature maintains PoE power to connected devices even when the switch undergoes a soft reboot or firmware upgrade. It ensures uninterrupted power delivery, preventing devices from losing power during such events. To enable Perpetual PoE, use the same command in interface configuration mode:

By configuring this command, the switch provides continuous PoE power during reboots.

For more detailed information on these features and their configuration, refer to the RUCKUS Community Forum post titled "Things to consider about PoE at a glance, when deploying."

Ruckus Wireless Community

In the Spanning Tree Protocol (STP), the root bridge is the central reference point for all spanning tree calculations. The election of the root bridge is determined by the bridge ID (BID), which comprises two components:

Bridge Priority:

A configurable value ranging from 0 to 65,535, in increments of 4,096. The default priority is typically 32,768.

MAC Address:

The unique hardware address of the switch.

Root Bridge Election Process:

Lowest Bridge ID Selection:

STP elects the switch with the lowest bridge ID as the root bridge. The bridge ID is determined by combining the bridge priority and the MAC address.

Priority Comparison:

Switches first compare the bridge priority values. The switch with the lowest priority value is favored.

MAC Address Comparison:

If multiple switches share the same priority value, the switch with the lowest MAC address becomes the root bridge.

Example:

Switch A:

Priority: 32,768

MAC Address: 00:1A:2B:3C:4D:5E

Switch B:

Priority: 32,768

MAC Address: 00:1A:2B:3C:4D:5F

In this scenario, both switches have the same priority. Therefore, STP compares the MAC addresses, and Switch A, with the lower MAC address, is elected as the root bridge.

Key Points:

Enabling root guard on a device does not influence its election as the root bridge; instead, it prevents designated ports from becoming root ports.

The device with the lowest bridge ID (combination of priority and MAC address) is elected as the root bridge.

A lower bridge priority value increases the likelihood of a switch becoming the root bridge.

References:

Root Bridge Election in Spanning Tree Protocol

Spanning Tree Protocol – Part 3: Bridge ID, Priority, System ID

Sources

In RUCKUS ICX switches, a Virtual Ethernet (VE) interface, also known as a routed interface, is used to route traffic between VLANs. To create a VE interface and associate it with a VLAN, follow these steps:

Access VLAN Configuration Mode: Enter global configuration mode and then VLAN configuration mode for the desired VLAN. For VLAN 2, the commands are:

Create and Associate VE Interface: Within VLAN configuration mode, create the VE interface and associate it with the VLAN using the router-interface command:

router-interface ve 2

This command creates VE interface 2 and links it to VLAN 2.

Configure the VE Interface: Exit VLAN configuration mode and enter interface configuration mode for the newly created VE interface to assign an IP address:

interface ve 2

ip address

Replace and with the desired IP address and subnet mask for the VE interface.

By following these steps, you create a VE interface that enables routing for the associated VLAN. This configuration is essential for inter-VLAN routing,

Dynamic ARP Inspection (DAI) is a security feature that intercepts and validates Address Resolution Protocol (ARP) packets in a network. It ensures that only legitimate ARP requests and responses are relayed, preventing ARP spoofing and man-in-the-middle attacks.

Conditions Allowing ARP Packets to Pass DAI Checks:

IP/MAC Pair in the DHCP Binding Database:

When DHCP snooping is enabled, the switch maintains a binding table of IP-to-MAC address mappings assigned by the DHCP server.

DAI uses this database to verify that ARP packets have legitimate IP/MAC address pairs.

If the ARP packet's IP/MAC pair matches an entry in the DHCP binding database, it passes the DAI check.

Static ARP Entry with Inspection Flag Set:

Administrators can configure static ARP entries for known devices, marking them as trusted for DAI purposes.

These entries include the IP/MAC pair and are flagged to bypass DAI checks.

An ARP packet matching a static entry with the inspection flag set will pass the DAI check.

Request Originated on a Trusted Port:

Ports can be designated as trusted, typically those connected to other switches or network devices.

DAI does not inspect ARP packets arriving on trusted ports, assuming they are from legitimate sources.

Therefore, ARP requests or responses from a trusted port pass the DAI check.

References:

For more information on configuring DAI and related security features, refer to the RUCKUS FastIron Layer 3 Routing Configuration Guide: Dynamic ARP Inspection overview

Implementing DAI with these conditions helps protect the network from ARP-based attacks by ensuring that only validated ARP traffic is permitted.