User Guide

Command ping a very common method for troubleshooting the accessibility of devices.
It uses a series of Internet Control Message Protocol (ICMP) Echo messages to
determine:
• Whether a remote host is active or inactive.
• The round-trip delay in communicating with the host.
• Packet loss.
Command ping first sends an echo request packet to an address, then waits for a reply,
the reply will be recorded with latency. The default ping packet is 6, Ctrl+c can
terminate ping.
Traceroute
Command traceroute is used to discover the routes that packets actually take when
traveling to their destination. The network device sends out a sequence of User
Datagram Protocol (UDP) datagrams to an invalid port address at the remote host.
Three datagrams are sent, each with a Time-To-Live (TTL) field value set to one. The
TTL value of 1 causes the datagram to "timeout" as soon as it hits the first router in the
path; this router then responds with an ICMP Time Exceeded Message (TEM) indicating
that the datagram has expired.
Another three UDP messages are now sent, each with the TTL value set to 2, which
causes the second router to return ICMP TEMs. This process continues until the packets
actually reach the other destination. Since these datagrams are trying to access an
invalid port at the destination host, ICMP Port Unreachable Messages are returned,
indicating an unreachable port; this event signals the Traceroute program that it is
finished.
The purpose behind this is to record the source of each ICMP Time Exceeded Message
to provide a trace of the path the packet took to reach the destination.
Table 40 ping & traceroute configuration
Command Syntax Command Mode Purpose
ping { <A.B.C.D> |
<hostname> }
Privileged EXEC Detect remote device accessibility or not.
traceroute { <A.B.C.D> |
<hostname> }
Privileged EXEC Trace the path of the packet to
destination.
MSR2000# ping 192.168.15.126
PING 192.168.15.126 (192.168.15.126): 56 data bytes
84 bytes from 192.168.15.126: icmp_seq=0 ttl=64 time=8.7 ms
84 bytes from 192.168.15.126: icmp_seq=1 ttl=64 time=0.8 ms
84 bytes from 192.168.15.126: icmp_seq=2 ttl=64 time=1.0 ms
84 bytes from 192.168.15.126: icmp_seq=3 ttl=64 time=0.9 ms
84 bytes from 192.168.15.126: icmp_seq=4 ttl=64 time=1.0 ms
84 bytes from 192.168.15.126: icmp_seq=5 ttl=64 time=0.9 ms
--- 192.168.15.126 ping statistics ---
6 packets transmitted, 6 packets received, 0% packet loss
round-trip min/avg/max = 0.8/2.2/8.7 ms
MSR2000# ping 192.168.15.11
MSR2000 CLI Configuration Guide
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