ZyXEL Communications ES3500 Series User manual

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Switch Series
ES 3500 Series
GS 1920 Series / 2210 Series / 3700 Series
XGS 2210 Series / 3700 Series / 4500 Series
XS 1920-12 / 3700-24/ 3900-48
Firmware Version 4.00~4.30
Edition 1, 9/2016
Troubleshooting Guide
Default Login Details
LAN Port IP Address
https://192.168.1.1
User Name
admin
Password
1234

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1!How%to%Troubleshoot%Switch%Related%Issues%......................................................%3!
2!Symptom%of%Troubleshooting%...........................................................................%7!
3!Basic%Information%.............................................................................................%9!
4!Hardware%Monitor%Status%...............................................................................%11!
5!Switch%Auto-Reboot,%Crash%.............................................................................%15!
6!Troubleshooting%for%Loop%...............................................................................%16!
7!Troubleshooting%for%VLAN%..............................................................................%25!
8!Troubleshooting%for%Multicast%........................................................................%37!
9!Troubleshooting%for%Layer%2%IGMP%Snooping%...................................................%44!
10!Troubleshooting%for%L3%IGMP%Routing%..........................................................%56!
11!Troubleshooting%for%Multicast%VLAN%Registration%........................................%64!
12!Troubleshooting%for%IP%Source%Guard%...........................................................%76!
13!Troubleshooting%for%DHCP%Relay%..................................................................%86!
14!Troubleshooting%for%DHCP%Server%................................................................%97!
15!Troubleshooting%for%ACL%............................................................................%105!
16!Troubleshooting%for%Routing%......................................................................%116!
17!Troubleshooting%for%CPU%high%....................................................................%128!
18!Troubleshooting%for%PoE%............................................................................%129!

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1 How to Troubleshoot Switch Related Issues
This document describes the necessary process for troubleshooting
Zyxel Switch related issues.
STEP 1: Information Gathering
Start by gathering basic and general information. This is necessary for
the following reasons:
l Attempt to locally reproduce issue.
l Gain perspective over customer’s network architecture.
l Quickly identify devices.
You can verify which information is relevant for troubleshooting by
reviewing “Basic information”.
STEP 2: Identifying the Symptom
Analyze the problem that your customer is experiencing. Avoid using
subjective responses. Rely on objective responses.
Example of subjective responses:
l The <device> stopped working sometimes.
l <Device> crashes all the time.
l All devices cannot access the Internet.
Example of objective responses:
l <Device> undergoes unexpected reboot sometimes.
l Console CLI does not show any output.
l Bob’s laptop cannot access the Internet.
Once you can clearly identify the symptom and the affected devices,
refer to “Symptom of Troubleshooting” and locate the symptom that
best matches customer’s description.

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STEP 3: Following the Troubleshooting Guides
Each symptoms will have a list of corresponding Troubleshooting Steps
that you will need to look through.
Example:
If customer encounters symptom involving “PC cannot communicate
with other devices”, they will start the troubleshooting process by
reviewing the following order:
- Troubleshooting of VLAN
- Troubleshooting of Loop
- Troubleshooting of IP Source Guard
- Troubleshooting of Routing
- Troubleshooting of ACL
STEP 4: The Troubleshooting Process
Most of the Troubleshooting guide follows the common schema:
START: refers to where the troubleshooting process begins.
Initiate: refers to how the symptom is triggered.

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Verify: indicates whether the issue is resolved or not.
FINISH: is achieved when symptom related to this feature has either
been resolved, or never encountered in the first place. Reaching
this process will usually inform you to proceed to the next
troubleshooting guide/agenda.
Reconfigure: refers to the common possible misconfigurations that
may cause the observable symptoms.
OTHERS: this is achieved when symptom is caused by software
malfunction or inter-operability issues between other devices. You
will ultimately end-up in this section when all possible
reconfigurations fails to pass the Verify stage. The OTHERS section
will be occasionally updated as CSO continues to find new and
unique problems.
If you end-up in the OTHERS section but cannot proceed further,
then kindly consult with Zyxel’s CSO.
Example:

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2 Symptom of Troubleshooting
Following are some common issue symptom report from customer, according to the
symptoms of these problems, you can follow the below step and it will help you
speed up to identify the cause of the problem.
1. Switch randomly crash.
Troubleshooting Step:
l Crash
2. Abnormal Status with PWR, SYS, ALM LED
Troubleshooting Step:
l HW Monitor
3. PC cannot communicate with other devices.
Troubleshooting Step:
l VLAN
l LoopGuard
l IP Source Guard
l Routing
l ACL
4. Client cannot get ip address from DHCP Server
Troubleshooting Step:
l VLAN
l LoopGuard
l IP Source Guard
l DHCP Server
l DHCP Relay
l ACL

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5. Administrator cannot manage the switches.
Troubleshooting Step:
l VLAN
l Management
l DHCP Relay
l ACL
6. CCTV cannot watch Channel, LAG, Delay, Mosaics or Freeze.
Troubleshooting Step:
l VLAN
l Multicast Troubleshooting.
l L2 IGMP Snooping
l L3 IGMP Routing
l MVR
7. IP phone or IP Camera cannot be power on by PoE Switch.
Troubleshooting Step:
l PoE Troubleshooting Guide.

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3 Basic Information
If switch happen some problem, following are some general information may
need to confirm first:
l Firmware Version
l Configuration
l Tech-Support Logs
l Network Topology
Check Firmware Version
1. WebGUI:
Figure 1 Basic Setting > System Info
2. CLI:
Figure 2 Enter CLI command “show system-information”.

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Configuration
1. WebGUI:
Figure 3 Management > Maintenance > Backup Configuration
Tech-Support Logs
1. CLI:
Figure 4 Enter CLI command “show tech-support”.
Topology
In order to speed up to understand the issue how to happen, the topology
information is important for troubleshooting.