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Network Switch Stacking: FAQ and Troubleshooting Guide
Welcome to this guide. This article aims to consolidate the most frequently encountered technical issues and solutions when setting up and maintaining Network Switch Stacking.Before you begin troubleshooting, please ensure your equipment meets the following basic requirements: All switch models support stacking…
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Resolving Loop Guard and RSTP Conflict in NCC
Nebula Control Center (NCC) might prevent administrators from enabling Loop Guard on specific switch ports if RSTP was previously enabled on the port level but is currently disabled globally. Workaround to Enable Loop Guard If you experience an issue where the RSTP option on a switch port is greyed out but still blocks…
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Troubleshooting Nebula Configuration Desynchronization on Switches
Nebula Control Center (NCC) provides a centralized management platform, but occasionally a configuration drift or desynchronization may occur where the local switch state does not match the Nebula portal while the status incorrectly shows as "up to date." Resolving Desynchronization Issues When a silent configuration…
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Troubleshooting Intermittent Disconnections on Nebula Switches
When multiple switches in a network intermittently go offline for short periods (e.g., 3 to 5 minutes) while the primary gateway remains online, administrative action is required to isolate whether the root cause lies in physical connectivity, IP configuration, or port blocking. Basic IP and Connection Verification Instead…
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Zyxel Switch Support Plan for Post-Quantum Cryptography (PQC)
Zyxel keeps evaluating next-generation security standards to ensure our networking solutions align with security advancements and market demands. Current Roadmap and Planning While Post-Quantum Cryptography (PQC) represents the future of secure data transmission, it is currently in its early stages of deployment across the…
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Troubleshooting and RMA Process for GS1920 Switch Fan Issues
When a GS1920 switch experiences persistent fan noise and runs continuously at maximum RPM, it may indicate either a configuration issue or a physical hardware defect. This article outlines the essential steps to diagnose the problem and proceed with an RMA if necessary. Initial Troubleshooting Steps If your switch fans…
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Troubleshooting Network Storms and Loops
When a network loop occurs, particularly on unmanaged switches, it can trigger intense broadcast and multicast storms that degrade performance or disconnect devices. Identifying Network Storm Symptoms Network storms often manifest through severe connectivity issues rather than isolated hardware failures. Administrators can…
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XMG1915-18EP Fan Behavior and Noise Troubleshooting
The XMG1915-18EP smart managed switch utilizes an active cooling fan as part of its standard hardware design. This article clarifies the switch's behavior if the fan is disconnected and outlines the troubleshooting options for excessive fan noise. Fan Status and Boot Behavior The XMG1915-18EP firmware does not actively…
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Transitioning Switch IP from DHCP to Static without Disconnection
When changing a switch's IP address from DHCP to static, remote users may experience a sudden loss of connection. This occurs because the static IP and the default gateway must be configured separately, which temporarily leaves the switch without a valid gateway during the transition. Step-by-Step Configuration Workaround…
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Troubleshooting GS1900-24HPv2 Switch Disconnections
When experiencing simultaneous client disconnections or intermittent network outages on GS1900 series switches, the root cause is frequently linked to unstable fiber uplinks rather than individual client port failures. Analyzing Link Instability on Fiber Uplinks Reviewing the switch diagnostic logs and status helps…
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Preventing Nebula Cloud Configuration from Overwriting Local Switch Settings
Preventing Nebula Cloud Configuration from Overwriting Local Switch Settings When managing network switches within the Nebula Control Center (NCC), maintaining configuration consistency is critical. Making local changes on Nebula-managed devices can lead to synchronization issues and unintended configuration rollbacks…
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Resolving Switch Ports Stuck in Err-Disable State Triggered by BPDU Guard
Nebula switches secure your network by placing ports into an err-disable state when BPDU Guard is triggered. This article explains how to successfully recover and restore links on ports that have been blocked due to BPDU Guard activity. Recovering Ports from Err-Disable State When BPDU Guard is triggered, affected switch…
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Nebula Switch Monitoring Data and Port Status Synchronization Issues
When managing Nebula-controlled switches, ensuring synchronized time and communication with Nebula Control Center (NCC) is critical for rendering accurate port status and real-time statistics. Troubleshooting Synchronization Failures If switches show as online in Nebula but their port configurations, local information, and…
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Troubleshooting Poor Cable Quality and CRC Errors on Switch Ports
Nebula proactively monitors switch port connections and sends notifications when issues like "Poor cable quality" are detected, helping administrators preemptively identify and resolve physical layer degradations. Analyzing Port Error Packets When a "Poor cable quality" alert is triggered on a switch port, administrators…
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Troubleshooting Switches Offline or Not Showing in NCC
When switches do not appear online or fail to register in the Nebula Control Center (NCC), administrators can follow structured diagnostic steps to restore connectivity and identify the root cause. Primary Connectivity and Firmware Verification Before deeper troubleshooting, administrators should distinguish whether the…
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Troubleshooting Port Flapping and Storm Detection on GS1920 Switches
When deploying Access Points (APs) on GS1920 switches, administrators may occasionally encounter severe and continuous link up/down (port flapping) issues accompanied by loop or storm detections, even when physical diagnostics report normal status. Isolating the Port Flapping Issue To effectively diagnose persistent port…
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RMirror and Cross-Slot Stacking Limitations on Legacy Switches
When utilizing port mirroring on stacked switches, users may encounter limitations when attempting to mirror traffic across different hardware slots. This article provides information on hardware restrictions and how to configure RMirror as a workaround. Cross-Slot Mirroring Limitations On earlier legacy switch platforms…
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Troubleshooting Switch Port Flapping Issues
When deploying switches such as the XGS1930 series in local networks, port flapping on client connections can occasionally interrupt network stability. This article addresses how to identify, troubleshoot, and resolve continuous link-up and link-down behavior on specific switch ports. Port Flapping Symptoms and…
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Resolving Missing Switch Port Status and IP Information in Nebula
When managing Zyxel switches through the Nebula Control Center (NCC), you may sometimes observe that the switch is online, but critical information such as port status and connected device IP addresses is missing from the Nebula dashboard. This article addresses how timezone synchronization affects data reporting and how…
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Resolving Configuration Loss on XGS2220 Switches Upgrading from V4.80 to V5.00
When upgrading XGS2220-30HP switches from firmware version V4.80 to V5.00, some users may experience configuration loss where settings revert to factory defaults. This issue typically occurs due to command translation mismatches related to the "Password complexity" feature during the transition. Configuration Loss Symptoms…