H3C S9500 Series User manual

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Table of Contents
i
Table of Contents
Chapter 1 System Maintaining and Debugging..........................................................................1-1
1.1 System Maintaining and Debugging Overview..................................................................1-1
1.1.1 Introduction to System Maintaining and Debugging ...............................................1-1
1.1.2 Introduction to System Debugging..........................................................................1-2
1.2 System Maintaining and Debugging..................................................................................1-3
1.2.1 System Maintaining.................................................................................................1-3
1.2.2 System Debugging..................................................................................................1-4
1.3 System Maintaining Example ............................................................................................1-5

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Chapter 1 System Maintaining and Debugging
1-1
Chapter 1 System Maintaining and Debugging
When maintaining and debugging the system, go to these sections for information you
are interested in:
zSystem Maintaining and Debugging Overview
zSystem Maintaining and Debugging
zSystem Maintaining Example
1.1 System Maintaining and Debugging Overview
1.1.1 Introduction to System Maintaining and Debugging
You can use the ping command and thetracert command to verify the current network
connectivity.
I. 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:
zInformation 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.
zIf within the period set by the timeout timer, the destination device has not received
the ICMP response, it displays the prompt information.
zThe ping command can apply to the destination’s name or IP address. If the
destination’s name is unknown, the prompt information is displayed.
zThe 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.

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Chapter 1 System Maintaining and Debugging
1-2
II. The tracert command
By using the tracert command, you can trace the switches 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 routing device that first receives the packet; the value of TTL
decreases by 1 by each hop) 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 switch.
3) The source device sends a packet with a TTL value of 2 to the destination device.
4) The second hop responds with a TTL-expired ICMP message, which gives the
source device the address of the second routing device.
5) The above process continues until the ultimate destination device is reached. In
this way, the source device can trace the addresses of all the routing devices that
a packet traverses from the source device to the destination device.
1.1.2 Introduction to System Debugging
The device provides various debugging functions. For the majority of protocols and
features supported, the system provides corresponding debugging functions to help
users diagnose errors.
The following two switches control the display of debugging information:
zProtocol debugging switch, which controls the output of protocol-specific
debugging information
zScreen output switch,which controls whether to display the debugging information
on a certain screen.
Figure 1-1 illustrates the relationship between the protocol debugging switch and the
screen output switch. Only when both are turned on can debugging information be
output on a terminal.

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Chapter 1 System Maintaining and Debugging
1-3
Figure 1-1 The relationship between the protocol and screen debugging switch
1.2 System Maintaining and Debugging
1.2.1 System Maintaining
To do… Use the command… Remarks
ping [ ip ] [ -a source-ip | -c count |
-f | -h ttl | -iinterface-type
interface-number | -m interval | -n
| -p pad | -q | -r | -s packet-size | -t
timeout | -tos tos | -v |
-vpn-instance
vpn-instance-name ] *
remote-system
Optional
Used in IPv4 network
Available in any view
Check whether a
specified IP
address can be
reached ping [ ipv6 ] [ -asource-ip | -c
count | -m interval | -s packet-size
| -t timeout ] * remote-system [ -i
interface-type interface-number ]
Optional
Used in IPv6 network
Available in any view
tracert [ -a source-ip | -f first-ttl |
-m max-ttl | -p port | -q
packet-number | -vpn-instance
vpn-instance-name |-w timeout ] *
remote-system
Optional
Used in IPv4 network
Available in any view
View the routes
from the source to
the destination tracert [ ipv6 ] [-f first-ttl | -m
max-ttl | -p port | -q
packet-number | -w timeout ] *
remote-system
Optional
Used in IPv6 network
Available in any view

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Chapter 1 System Maintaining and Debugging
1-4
Note:
zFor a low-speed network, you are recommended to set a larger value for the timeout
timer (indicated by the -t parameter in the command) when configuring the ping
command.
zOnly the directly connected segment address can be pinged if the outgoing interface
is specified with the -i argument.
1.2.2 System Debugging
To do… Use the command… Remarks
Enable debugging for a
specified module
debugging { all [ timeout
time ] | module-name
[ option ] }
Required
Disabled by default
Available in user view
Enable the terminal
monitoring terminal monitor
Optional
The terminal monitoring
on the console is enabled
by default and that on the
monitoring terminal is
disabled by default.
Enable the terminal
debugging terminal debugging Required
Disabled by default
Available in user view
Display the enabled
debugging functions
display debugging
[interface interface-type
interface-number ]
[module-name ]
Optional
Available in any view
Display information about
the optical modules
connected to the optical
interfaces on the switch
display lpu fiber-module
[ interface-type
interface-number ]
Optional
Available in any view

Operation Manual – System Maintaining and Debugging
H3C S9500 Series Routing Switches Chapter 1 System Maintaining and Debugging
1-5
Note:
zThe debugging commands are usually used by administrators in diagnosing
network failure.
zOutput of the debugging information may reduce system efficiency, especially
during execution of the debugging all command.
zAfter completing the debugging, you are recommended to use the undo debugging
all command to disable all the debugging functions.
zYou must configure the debugging,terminal debugging and terminal monitor
commands first to display the detailed debugging information on the terminal. For
the detailed description on the terminal debugging and terminal monitor
commands, refer to Information Center Commands in the System Volume.
1.3 System Maintaining Example
I. Network requirements
zThe IP address of the destination device is 10.1.1.4.
zDisplay the routing devices a packet traverses from the current device to the
destination device.
II. Network diagram (omitted here)
III. Configuration procedure
<Sysname> tracert nis.nsf.net
traceroute to nis.nsf.net (10.1.1.4) 30 hops max, 40 bytes packet
1 128.3.112.1 19 ms 19 ms 10 ms
2 128.32.216.1 39 ms 39 ms 19 ms
3 128.32.136.23 39 ms 40 ms 39 ms
4 128.32.168.22 39 ms 39 ms 39 ms
5 128.32.197.4 40 ms 59 ms 59 ms
6 131.119.2.5 59 ms 59 ms 59 ms
7 129.140.70.13 99 ms 99 ms 80 ms
8 129.140.71.6 139 ms 239 ms 319 ms
9 129.140.81.7 220 ms 199 ms 199 ms
10 10.1.1.4 239 ms 239 ms 239 ms
The above output shows that a packet traverses nine routing devices from the source to
the destination device.