H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 572)

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System Maintaining and Debugging
When maintaining and debugging the system, go to these sections for information you are interested in:
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System Maintaining and Debugging Overview
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System Maintaining and Debugging
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System Maintaining Example
System Maintaining and Debugging Overview
Introduction to System Maintaining
You can use the ping command and the tracert command to verify the current network connectivity.
The ping command
You can use the ping command to verify whether a device with a specified address is reachable, and to
examine network connectivity.
The ping command involves the following steps in its execution:
1) The source device sends an ICMP echo request to the destination device.
2) If the network is functioning properly, the destination device responds by sending an ICMP echo
reply to the source device after receiving the ICMP echo request.
3) If there is network failure, the source device displays timeout or destination unreachable.
4) Display related statistics.
Output of the ping command includes:
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Information on the destination’s responses towards each ICMP echo request, if the source device
has received the ICMP echo reply within the timeout time, it displays the number of bytes of the
echo reply, the message sequence number, Time to Live (TTL), and the response time.
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If within the period set by the timeout timer, the destination device has not received the ICMP
response, it displays the prompt information.
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The ping command can apply to the destination’s name or IP address. If the destination’s name is
unknown, the prompt information is displayed.
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The statistics during the ping operation, which include number of packets sent, number of echo
reply messages received, percentage of messages not received, the minimum, average, and
maximum response time.
The tracert command
By using the tracert command, you can trace the routers involved in delivering a packet from source to
destination. This is useful for identification of failed node(s) in the event of network failure.
The tracert command involves the following steps in its execution:
1) The source device sends a packet with a TTL value of 1 to the destination device.
2) The first hop (the router that first receives the packet) responds by sending a TTL-expired ICMP
message to the source, with its IP address encapsulated. In this way, the source device can get the
address of the first router.