Using Diagnostic Tools; Overview; Ping; Traceroute - HP 1910 User Manual

Using diagnostic tools

Overview

Ping

Use ping to test connectivity to a specified address.
Ping operates as follows:
The source device sends an ICMP echo request (ECHO-REQUEST) to the destination device.
1.
The destination device responds by sending an ICMP echo reply (ECHO-REPLY) to the source
2.
device after receiving the ICMP echo request.
The source device displays related statistics after receiving the reply.
3.
Output of the ping command falls into the following:
• You can ping the IP address or the host name of a destination device. If the target host name cannot
be resolved, the source device outputs related information.
If the source device does not receive an ICMP echo reply within the timeout time, it displays prompt
•
information and ping statistics. If the source device receives an ICMP echo reply within the timeout
time, it displays the number of bytes the echo reply has, message sequence number, Time to Live
(TTL), response time, and ping statistics.
Ping statistics include the number of packets sent, number of echo reply messages received, percentage
of messages not received, and the minimum, average, and maximum response time.

Traceroute

By using the traceroute command, you can view the Layer 3 devices involved in delivering a packet from
source to destination. This function is useful for identification of failed node(s) in the event of network
failure.
You can trace route the IP address or the host name of a destination device. If the target host name cannot
be resolved, the source device outputs related information.
Traceroute operates as follows:
The source device sends a packet with a TTL value of 1 to the destination device.
1.
The first hop (the Layer 3 device that first receives the packet) sends a TTL-expired ICMP message
2.
to the source. The source device can get the address of the first Layer 3 device from the ICMP
message.
The source device sends a packet with a TTL value of 2 to the destination device.
3.
The second hop responds with a TTL-expired ICMP message, which gives the source device the
4.
address of the second Layer 3 device.
The above process continues until the packet reaches the destination device. The destination
5.
device responds with a port-unreachable ICMP message to the source so the source device can get
the IP address of the last device on the path.
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