RCNI Exam Dumps - RUCKUS High-stakes Industry Certifications Questions and Answers

The RUCKUS ICX7850 series offers high-performance switches suitable for core and aggregation layers in enterprise networks. Among the models in this series:

ICX7850-32Q:

Overview:

Designed for high-density 100GbE deployments.

Port Configuration:

32 ports of 100GbE QSFP28.

Use Case:

Ideal for environments requiring extensive 100GbE connectivity, such as data centers or large enterprise cores.

ICX7850-48F:

Overview:

Designed for high-density 25GbE deployments with additional uplink capabilities.

Port Configuration:

48 ports of 1/10/25GbE SFP28.

8 ports of 40/100GbE QSFP28 for uplinks or stacking.

Use Case:

Suitable for aggregation layers where a mix of 25GbE access ports and high-speed uplinks are needed.

ICX7750-32Q:

Overview:

Part of the ICX7750 series, designed for high-performance aggregation and core layers.

Port Configuration:

32 ports of 40GbE QSFP+.

Supports breakout cables for 10GbE connections.

Use Case:

Suitable for networks requiring 40GbE connectivity with flexibility for 10GbE access.

ICX7850-48FS:

Overview:

Similar to the ICX7850-48F but includes MACsec support for enhanced security.

Port Configuration:

48 ports of 1/10/25GbE SFP28 with MACsec.

8 ports of 40/100GbE QSFP28 for uplinks or stacking.

Use Case:

Ideal for secure aggregation layers requiring MACsec encryption.

References:

For detailed specifications, refer to the ICX 7850 data sheet: ICX 7850 Data Sheet

In summary, the ICX7850-32Q model offers the highest number of 100GbE ports among the listed options, making it the optimal choice for scenarios demanding extensive 100GbE connectivity.

In network communications, when an IP packet traverses multiple subnets to reach its destination, certain header information is modified at each hop to facilitate proper routing and delivery.

Destination MAC Address:

Role: The Media Access Control (MAC) address is a hardware identifier used at the Data Link layer (Layer 2) of the OSI model.

Update Process:

As a packet moves from one router to the next, the destination MAC address is updated to reflect the MAC address of the next-hop device.

This ensures that the packet is correctly forwarded at the Data Link layer within each local network segment.

Explanation:

When a router forwards a packet, it encapsulates the IP packet within a new Ethernet frame.

The router sets the destination MAC address in this frame to the MAC address of the next-hop router or the final destination device if it is on the same local network.

This process repeats at each hop, with each router updating the destination MAC address to ensure proper Layer 2 delivery.

Other Header Fields:

Destination IP Address:

Remains unchanged throughout the packet's journey, ensuring end-to-end delivery to the correct device.

Source IP Address:

Also remains unchanged, identifying the original sender of the packet.

Subnet Mask:

Not a field within the packet header; it is used by routers to determine the network portion of an IP address but is not transmitted with the packet.

References:

For a detailed understanding of how routers handle packet forwarding and the role of MAC addresses in this process, refer to the RUCKUS ICX Switch Configuration Guide, which provides insights into Layer 2 and Layer 3 forwarding mechanisms.

RUCKUS ICX switches are designed to store multiple software images simultaneously, allowing network administrators to manage firmware versions effectively. The maximum number of software images that can be stored on an ICX switch is three.

Image Storage Structure:

Primary Image:

The main firmware image that the switch loads during the boot process.

Secondary Image:

An alternative firmware image that can be used for redundancy or testing purposes.

Tertiary (or Additional) Image:

A third firmware image slot available for further flexibility in image management.

Managing Software Images:

Viewing Stored Images:

To display the software images stored on the switch, use the following command:

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show flash

This command lists all firmware images present in the switch's flash memory.

Setting Boot Preferences:

To specify which image the switch should load on the next reboot, use:

sql

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boot system flash primary

Replace primary with secondary or tertiary as needed.

Upgrading Firmware:

When upgrading the switch firmware, you can upload the new image to any of the available slots (primary, secondary, or tertiary) without overwriting existing images, providing a fallback option if needed.

Best Practices:

Maintain Multiple Images:

Keeping multiple firmware images allows for quick recovery in case of issues with the current running image.

Regular Updates:

Ensure that the stored images are up-to-date to maintain security and feature enhancements.

Consistent Configuration:

After uploading a new image, verify that the switch configuration is compatible with the firmware version to prevent potential issues.

References:

RUCKUS FastIron 08.0.90 Command Reference Guide

In RUCKUS ICX switches, VLAN 1 is the default VLAN and is typically used for management purposes. By default, all ports are members of VLAN 1 as untagged. Attempting to configure VLAN 1 as tagged on a port can result in an error, as the system restricts tagging the default VLAN.

Understanding the Error:

RKUS-01(config)# vlan 1

RKUS-01(config-vlan-1)# tagged ethernet 1/2/1

Invalid input -> tagged ethernet 1/2/1

Type ? for a list

This error occurs because the switch does not allow tagging of the default VLAN (VLAN 1) on any interface.

Resolution:

Option 1: Use a Different VLAN for Tagging

Create a new VLAN (e.g., VLAN 2) and configure it as tagged on the desired port.

RKUS-01(config)# vlan 2

RKUS-01(config-vlan-2)# tagged ethernet 1/2/1

Option 2: Change the Default VLAN ID

If you must use VLAN 1 as tagged, you can change the default VLAN ID to another VLAN (e.g., VLAN 2), allowing VLAN 1 to be configured as tagged.

RKUS-01(config)# default-vlan-id 2

RKUS-01(config)# vlan 1

RKUS-01(config-vlan-1)# tagged ethernet 1/2/1

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

When a high CPU utilization alert is triggered on a RUCKUS ICX switch, it's essential to identify the processes consuming excessive CPU resources. The show cpu tasks command provides detailed information about active processes and their CPU usage.

Command Usage:

show cpu tasks

Output Example:

Task Name CPU Time (ms) Invocations Avg Time (us)

------------------ -------------- ------------ -------------

TaskA 5000 1000 5000

TaskB 3000 1500 2000

In this output:

Task Name lists the names of active processes.

CPU Time (ms) indicates the total CPU time consumed by each process in milliseconds.

Invocations shows how many times each process has been called.

Avg Time (us) represents the average time per invocation in microseconds.

By analyzing this data, administrators can pinpoint processes that are utilizing disproportionate CPU resources, facilitating targeted troubleshooting and optimization.

Understanding Bridge Priority:

The bridge priority in the Spanning Tree Protocol (STP) is represented in hexadecimal format in RUCKUS ICX switches.

In the output, the bridge priority is a combination of the priority value (default is 32768 or 0x8000 in hex) and the VLAN ID.

Why It Is 8000:

Unless explicitly modified, the default bridge priority is 8000 in hexadecimal.

Why Other Options Don't Apply:

B. 0: This value does not align with the default or modified priority values.

C. 9c49: This might represent a different component of the output, such as MAC address.

D. 20009: This is an incorrect representation of the bridge priority.

References:

ICX Spanning Tree Configuration Guide: RUCKUS Documentation

RSTP and Legacy 802.1D Compatibility:

RSTP (802.1w) can interoperate with legacy switches running STP (802.1D). However, the legacy switches use different timers and convergence mechanisms, which can lead to delays.

Optimizing Timers for Legacy Edge Switches:

The edge switches running 802.1D rely on BPDU timing set by the upstream aggregation switches.

To influence the convergence time, the timers such as hello time, max age, and forward delay must be adjusted on the aggregation switches connected to these legacy edge switches. This ensures better compatibility and faster convergence.

Why Not Other Options?

A: The route-only port does not participate in STP.

B: Timers cannot be modified on legacy switches themselves as they strictly follow 802.1D standards.

D: The root bridge sets global parameters but does not address edge-specific timer optimization.

References:

RUCKUS RSTP/802.1D Compatibility Guide: RUCKUS Documentation

To monitor and manage the PoE power budget on RUCKUS ICX switches, the following commands are utilized:

show inline power Command:

Purpose: Displays a summary of the PoE status, including total power capacity, power consumption, and available power.

Usage:

Access the switch's command-line interface (CLI).

Enter the command:

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show inline power

Output Details:

Power Capacity: Total PoE power available on the switch.

Power Allocations: Power consumption per port, indicating which ports are supplying power to connected devices.

Example Output:

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Power Capacity: Total is 124000 mWatts. Current Free is 64000 mWatts.

Power Allocations: Requests Honored 8 times

Port Admin Oper ---Power (mWatts)--- PD Type PD Class Pri Fault/

State State Consumed Allocated Error

-----------------------------------------------------------------------------

1/1/1 On On 4733 30000 2P-IEEE Class 4 3 n/a

1/1/2 On Off 6015 30000 2P-IEEE Class 4 3 n/a

(additional ports)