3Com Switch 7757, Руководство по настройке

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N
ETWORK
C
ONNECTIVITY
T
EST
Network Connectivity
Test
ping You can use the ping command to check the network connectivity and the
reachability of a host.
This command can output the following results:
■
Response status for each ping packet. If no response packet is received within
the timeout time, the message “Request time out” is displayed. Otherwise, the
number of data bytes, packet serial number, TTL (time to live) and response
time of the response packet are displayed.
■
Final statistics, including the numbers of sent packets and received response
packets, the unresponsive packet percentage, and the minimum, average and
maximum values of response time.
tracert You can use the tracert command to trace the gateways a packet passes during
its journey from the source to the destination. This command is mainly used to
check the network connectivity. It can help you locate the trouble spot of the
network.
The executing procedure of the tracert command is as follows: First, the source
host sends a data packet with the TTL of 1, and the first hop device returns an
ICMP error message indicating that it cannot forward this packet because of TTL
timeout. Then, the source host resends the packet with the TTL of 2, and the
second hop device also returns an ICMP TTL timeout message. This procedure
goes on and on until the packet gets to the destination. During the procedure, the
system records the source address of each ICMP TTL timeout message in order to
offer the path that the packet passed through to the destination.
Table 672 The ping command
Operation Command
Support IP protocol ping [ -a ip-address | -c count | -d | -f | -h
ttl | -i interface-type interface-number | -n |
- p pattern | -q | -r | -s packetsize | -t
timeout | -tos tos | -v | ip ]* host-ip
Support IPX protocol ping ipx ipx-address [ -c count | -s
packetsize | -t timeout ]*
Support CLNS protocol ping clns nsap-address