HPE 5820X Series User manual

HPE 5820X & 5800 Switch Series
Network Management and Monitoring
Configuration Guide
Part number: 5998-7395R
Software version: Release 1810
Document version: 6W100-20160129

© Copyright 2016 Hewlett Packard Enterprise Development LP
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Contents
Using ping, tracert, and system debugging·····················································1
Ping····································································································································································1
Using a ping command to test network connectivity··················································································1
Ping example ·············································································································································1
Tracert································································································································································3
Prerequisites··············································································································································4
Using a tracert command to identify failed or all nodes in a path·······························································5
System debugging ·············································································································································5
Debugging information control switches ····································································································5
Debugging a feature module······················································································································6
Ping and tracert example···································································································································7
Configuring NTP ·····························································································9
Overview····························································································································································9
NTP application··········································································································································9
NTP advantages ········································································································································9
How NTP works ·········································································································································9
NTP message format·······························································································································10
Operation modes······································································································································12
NTP for VPNs···········································································································································14
NTP configuration task list ·······························································································································15
Configuring NTP operation modes···················································································································15
Configuring the client/server mode ··········································································································15
Configuring the symmetric peers mode ···································································································16
Configuring the broadcast mode··············································································································16
Configuring the multicast mode················································································································17
Configuring optional parameters······················································································································18
Specifying the source interface for NTP messages·················································································18
Disabling an interface from receiving NTP messages ·············································································18
Configuring the allowed maximum number of dynamic sessions ····························································19
Configuring the DSCP value for NTP messages ·····················································································19
Configuring access-control rights·····················································································································20
Configuration prerequisites······················································································································20
Configuration procedure···························································································································20
Configuring NTP authentication·······················································································································20
Configuring NTP authentication in client/server mode·············································································21
Configuring NTP authentication in symmetric peers mode······································································22
Configuring NTP authentication in broadcast mode·················································································23
Configuring NTP authentication in multicast mode··················································································24
Displaying and maintaining NTP······················································································································25
NTP configuration examples····························································································································25
Configuring the client/server mode ··········································································································25
Configuring the NTP symmetric mode·····································································································26
Configuring NTP broadcast mode············································································································28
Configuring NTP multicast mode ·············································································································29
Configuring NTP client/server mode with authentication ·········································································32
Configuring NTP broadcast mode with authentication·············································································33
Configuring MPLS VPN time synchronization in client/server mode························································36
Configuring MPLS VPN time synchronization in symmetric peers mode·················································37
Configuring the information center································································39
Overview··························································································································································39
Classification of system information·········································································································39
System information levels························································································································39
System information channels and output destinations·············································································40
Default output rules of system information·······························································································41
System information formats ·····················································································································41

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FIPS compliance··············································································································································44
Information center configuration task list ·········································································································44
Outputting system information to the console··································································································45
Outputting system information to the monitor terminal ····················································································45
Outputting system information to a log host·····································································································46
Outputting system information to the trap buffer······························································································47
Outputting system information to the log buffer ·······························································································48
Outputting system information to the SNMP module·······················································································49
Outputting system information to the Web interface························································································49
Saving system information to the log file ·········································································································50
Saving security logs into the security log file ···································································································51
Saving security logs into the security log file····························································································51
Managing the security log file···················································································································52
Enabling synchronous information output········································································································54
Disabling an interface from generating link up/down logging information························································55
Displaying and maintaining information center ································································································55
Information center configuration examples······································································································56
Outputting log information to the console·································································································56
Outputting log information to a UNIX log host··························································································57
Outputting log information to a Linux log host··························································································58
Saving security logs into the security log file····························································································59
Configuring SNMP························································································63
Overview··························································································································································63
FIPS compliance··············································································································································63
SNMP framework·····································································································································63
MIB and view-based MIB access control·································································································63
SNMP operations·····································································································································64
SNMP protocol versions···························································································································64
SNMP configuration task list····························································································································64
Configuring SNMP basic parameters···············································································································65
Configuring SNMPv3 basic parameters···································································································65
Configuring SNMPv1 or SNMPv2c basic parameters··············································································66
Switching the NM-specific interface index format ····························································································68
Configuration guidelines···························································································································68
Configuration procedure···························································································································69
Configuring SNMP logging·······························································································································69
Configuring SNMP traps ··································································································································69
Enabling SNMP traps·······························································································································70
Configuring the SNMP agent to send traps to a host···············································································70
Displaying and maintaining SNMP···················································································································72
SNMP configuration examples·························································································································72
SNMPv1/SNMPv2c configuration example······························································································72
SNMPv3 configuration example···············································································································74
SNMP logging configuration example······································································································75
Configuring RMON························································································78
Overview··························································································································································78
Working mechanism·································································································································78
RMON groups··········································································································································78
Configuring the RMON statistics function ········································································································80
Configuring the RMON Ethernet statistics function··················································································80
Configuring the RMON history statistics function·····················································································80
Configuring the RMON alarm function·············································································································81
Displaying and maintaining RMON··················································································································82
Ethernet statistics group configuration example ······························································································82
History group configuration example ···············································································································83
Alarm group configuration example ·················································································································85
Configuring port mirroring·············································································87
Overview··························································································································································87
Terminology ·············································································································································87

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Port mirroring classification and implementation······················································································88
Configuring local port mirroring························································································································90
Local port mirroring configuration task list································································································90
Creating a local mirroring group···············································································································91
Configuring source ports for a local mirroring group················································································91
Configuring source CPUs for a local mirroring group···············································································92
Configuring the monitor port for a local mirroring group···········································································92
Using the remote probe VLAN to enable local mirroring to support multiple monitor ports ·····················93
Configuring Layer 2 remote port mirroring·······································································································94
Layer 2 remote port mirroring configuration task list················································································94
Configuring a remote source group (on the source device)·····································································95
Configuring a remote destination group (on the destination device)························································98
Configuring Layer 3 remote port mirroring·······································································································99
Layer 3 remote port mirroring configuration task list··············································································100
Configuration prerequisites····················································································································100
Configuring a local mirroring group········································································································100
Configuring source ports for a local mirroring group··············································································101
Configuring source CPUs for a local mirroring group·············································································101
Configuring the monitor port for a local mirroring group·········································································102
Configuration restrictions and guidelines·······························································································103
Configuration procedure·························································································································103
Displaying and maintaining port mirroring······································································································103
Port mirroring configuration examples ···········································································································103
Local port mirroring configuration example····························································································104
Local port mirroring with multiple monitor ports configuration example·················································105
Layer 2 remote port mirroring configuration example ············································································106
Layer 3 remote port mirroring configuration example ············································································108
Configuring flow mirroring···········································································111
Overview························································································································································111
Remote flow mirroring overview·············································································································111
Flow mirroring configuration task list··············································································································111
Configuring flow mirroring······························································································································112
Configuring match criteria······················································································································112
Configuring different types of flow mirroring···························································································112
Configuring a QoS policy ·······················································································································113
Applying a QoS policy····························································································································113
Applying a QoS policy to the control plane ····························································································114
Displaying and maintaining flow mirroring ·····································································································115
Flow mirroring configuration examples··········································································································115
Flow mirroring configuration example····································································································115
Configuring NQA·························································································118
Overview························································································································································118
Collaboration··········································································································································118
Threshold monitoring ·····························································································································119
NQA configuration task list·····························································································································119
Configuring the NQA server···························································································································120
Configuring the NQA client ····························································································································121
Enabling the NQA client·························································································································121
Configuring an ICMP echo operation·····································································································121
Configuring a DHCP operation···············································································································122
Configuring a DNS operation·················································································································123
Configuring an FTP operation················································································································123
Configuring an HTTP operation ·············································································································124
Configuring a UDP jitter operation ·········································································································125
Configuring an SNMP operation ············································································································126
Configuring a TCP operation··················································································································127
Configuring a UDP echo operation ········································································································128
Configuring a voice operation ················································································································129
Configuring a DLSw operation···············································································································131
Configuring optional parameters for an NQA operation·········································································131

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Configuring the collaboration function····································································································132
Configuring threshold monitoring···········································································································133
Configuring the NQA statistics function··································································································136
Configuring the saving function of NQA history records ········································································136
Scheduling an NQA operation················································································································137
Displaying and maintaining NQA ···················································································································138
NQA configuration examples ·························································································································138
ICMP echo operation configuration example·························································································138
DHCP operation configuration example·································································································140
DNS operation configuration example ···································································································141
FTP operation configuration example····································································································142
HTTP operation configuration example··································································································144
UDP jitter operation configuration example····························································································145
SNMP operation configuration example·································································································147
TCP operation configuration example····································································································149
UDP echo operation configuration example···························································································150
Voice operation configuration example··································································································151
DLSw operation configuration example ·································································································154
NQA collaboration configuration example······························································································155
Configuring sFlow·······················································································158
sFlow configuration task list···························································································································158
Configuring the sFlow agent and sFlow collector information········································································159
Configuring flow sampling······························································································································159
Configuring counter sampling ························································································································160
Displaying and maintaining sFlow··················································································································160
sFlow configuration example ·························································································································160
Troubleshooting sFlow configuration ·············································································································162
The remote sFlow collector cannot receive sFlow packets····································································162
Configuring NetStream ···············································································163
Hardware compatibility···································································································································163
Overview························································································································································163
Terminology ···········································································································································163
NetStream key technologies··························································································································164
Flow aging··············································································································································164
Data export·············································································································································164
NetStream export formats······················································································································166
NetStream sampling and filtering···················································································································166
NetStream sampling·······························································································································166
NetStream filtering ·································································································································166
NetStream configuration task list ···················································································································166
Enabling NetStream·······································································································································167
Configuring NetStream filtering and sampling ·······························································································168
Configuring NetStream filtering··············································································································168
Configuring NetStream sampling···········································································································169
Configuring NetStream data export ···············································································································170
Configuring traditional data export·········································································································170
Configuring aggregation data export······································································································170
Configuring attributes of NetStream data export····························································································172
Configuring the refresh rate for NetStream version 9 templates····························································172
Configuring NetStream flow aging ·················································································································172
Flow aging methods·······························································································································172
Configuring NetStream flow aging ·········································································································173
Displaying and maintaining NetStream··········································································································173
NetStream configuration examples················································································································174
NetStream traditional data export configuration example······································································174
NetStream aggregation data export configuration example···································································174
Configuring IPv6 NetStream ·······································································177
Hardware compatibility···································································································································177
Overview························································································································································177

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Terminology ···········································································································································177
IPv6 NetStream key technologies··················································································································178
Flow aging··············································································································································178
Data export·············································································································································178
IPv6 NetStream export format················································································································179
IPv6 NetStream configuration task list···········································································································179
Enabling IPv6 NetStream on an interface······································································································180
Configuring IPv6 NetStream data export ·······································································································180
Configuring IPv6 NetStream traditional data export···············································································180
Configuring IPv6 NetStream aggregation data export ···········································································181
Configuring attributes of IPv6 NetStream data export ···················································································182
Displaying and maintaining IPv6 NetStream··································································································182
IPv6 NetStream configuration examples········································································································183
IPv6 NetStream traditional data export configuration example······························································183
IPv6 NetStream aggregation data export configuration example···························································184
Configuring a sampler·················································································186
Configuration procedure ································································································································186
Displaying and maintaining a sampler ···········································································································186
Sampler configuration example ·····················································································································187
Configuring IPC···························································································188
Overview························································································································································188
Node·······················································································································································188
Link·························································································································································188
Channel··················································································································································188
Packet sending modes···························································································································189
Enabling IPC performance statistics··············································································································189
Displaying and maintaining IPC·····················································································································190
Configuring PoE··························································································191
Overview························································································································································191
PoE configuration task list······························································································································191
Configuration guidelines·························································································································191
Enabling PoE for a PoE interface ··················································································································192
Detecting PDs················································································································································193
Enabling the PSE to detect nonstandard PDs ·······················································································193
Configuring a PD disconnection detection mode···················································································193
Configuring the maximum PoE interface power·····························································································194
Configuring PoE interface power management ·····························································································194
Configuring the PoE monitoring function ·······································································································195
Configuring PSE power monitoring········································································································195
Monitoring PD ········································································································································195
Configuring PoE interface through PoE profile ······························································································195
Configuring a PoE profile·······················································································································196
Applying a PoE profile····························································································································196
Upgrading PSE processing software in service·····························································································197
Displaying and maintaining PoE ····················································································································197
PoE configuration example····························································································································198
Troubleshooting PoE ·····································································································································199
Setting the priority of a PoE interface to critical fails··············································································199
Applying a PoE profile to a PoE interface fails·······················································································199
Configuring an AC input undervoltage threshold fails············································································199
Configuring CWMP·····················································································201
Overview························································································································································201
CWMP network framework ····················································································································201
Basic CWMP functions···························································································································202
CWMP mechanism ································································································································203
Restrictions and guidelines····························································································································205
CWMP configuration methods ·······················································································································205
Configuring ACS and CPE attributes through DHCP·············································································205

vi
Configuring the DNS server···················································································································206
Configuring ACS and CPE attributes through ACS················································································206
Configuring CWMP at the CLI················································································································206
Enabling CWMP·············································································································································207
Configuring the ACS attributes ······················································································································207
Configuring the ACS URL······················································································································208
Configuring the ACS username and password······················································································208
Configuring CPE attributes ····························································································································208
Configuring the CPE username and password······················································································208
Configuring the CWMP connection interface·························································································209
Sending Inform messages ·····················································································································209
Configuring the maximum number of attempts made to retry a connection···········································210
Configuring the close-wait timer of the CPE ··························································································210
Configuring the CPE working mode·······································································································211
Specifying an SSL client policy for HTTPS connection to ACS ·····························································211
Displaying and maintaining CWMP················································································································211
CWMP configuration example ·······················································································································212
Configuration guidelines·························································································································212
Network requirements····························································································································212
Configuration procedure·························································································································213
Configuring cluster management································································220
Cluster management overview ······················································································································220
Why cluster management ······················································································································220
Roles in a cluster····································································································································220
How a cluster works·······························································································································221
Cluster management configuration task list···································································································224
Configuring the management device ·············································································································225
Enabling NDP globally and for specific ports·························································································225
Configuring NDP parameters·················································································································226
Enabling NTDP globally and for specific ports·······················································································226
Configuring NTDP parameters···············································································································227
Manually collecting topology information ·······························································································227
Enabling the cluster function··················································································································228
Establishing a cluster·····························································································································228
Enabling management VLAN auto-negotiation······················································································229
Configuring communication between the management device and the member devices within a cluster
·······························································································································································229
Configuring cluster management protocol packets················································································230
Cluster member management················································································································231
Configuring the member devices ···················································································································231
Enabling NDP·········································································································································231
Enabling NTDP ······································································································································231
Manually collecting topology information ·······························································································231
Enabling the cluster function··················································································································232
Deleting a member device from a cluster·······························································································232
Configuring access between the management device and its member devices ···········································232
Adding a candidate device to a cluster ··········································································································233
Configuring advanced cluster management functions···················································································233
Configuring topology management········································································································233
Configuring interaction for a cluster ·······································································································234
SNMP configuration synchronization function························································································235
Configuring web user accounts in batches ····························································································236
Displaying and maintaining cluster management ··························································································236
Cluster management configuration example ·································································································237
Configuring packet capture·········································································240
Configuring the packet capture function ········································································································240
Displaying and maintaining packet capture ···································································································241
Packet capture configuration example···········································································································241

vii
Document conventions and icons·······························································243
Conventions···················································································································································243
Network topology icons··································································································································244
Support and other resources ······································································245
Accessing Hewlett Packard Enterprise Support ····························································································245
Accessing updates·········································································································································245
Websites ················································································································································246
Customer self repair·······························································································································246
Remote support······································································································································246
Documentation feedback ·······················································································································247
Index···········································································································248

1
Using ping, tracert, and system
debugging
Use the ping, tracert, and system debugging utilities to test network connectivity and identify network
problems.
Ping
The ping utility sends ICMP echo requests (ECHO-REQUEST) to the destination device. Upon
receiving the requests, the destination device responds with ICMP echo replies (ECHO-REPLY) to
the source device. The source device outputs statistics about the ping operation, including the
number of packets sent, number of echo replies received, and the round-trip time. You can measure
the network performance by analyzing these statistics.
Using a ping command to test network connectivity
Task Command Remarks
Test the network connectivity to
an IP address.
•For IPv4 networks:
ping [ ip ] [ -asource-ip | -c
count | -f | -httl | -i
interface-type
interface-number | -m
interval | -n | -p pad | -q | -r |
-s packet-size | -t timeout |
-tos tos | -v |-vpn-instance
vpn-instance-name ] * host
•For IPv6 networks:
ping ipv6 [ -a source-ipv6 |
-c count | -m interval | -s
packet-size | -t timeout | -tos
tos | -vpn-instance
vpn-instance-name ] * host
[ -i interface-type
interface-number ]
Use either approach.
Available in any view.
When you configure the ping command for a low-speed network, set a larger value for the -t timeout
option, the timeout timer.
For more information about the ping lsp command, see MPLS Command Reference.
Ping example
Network requirements
Test the network connectivity between Device A and Device C in Figure 1. If they can reach each
other, get detailed information about routes from Device Ato Device C.

2
Figure 1 Network diagram
Test procedure
# Use the ping command on DeviceA to test connectivity to Device C.
<DeviceA> ping 1.1.2.2
PING 1.1.2.2: 56 data bytes, press CTRL_C to break
Reply from 1.1.2.2: bytes=56 Sequence=1 ttl=254 time=205 ms
Reply from 1.1.2.2: bytes=56 Sequence=2 ttl=254 time=1 ms
Reply from 1.1.2.2: bytes=56 Sequence=3 ttl=254 time=1 ms
Reply from 1.1.2.2: bytes=56 Sequence=4 ttl=254 time=1 ms
Reply from 1.1.2.2: bytes=56 Sequence=5 ttl=254 time=1 ms
--- 1.1.2.2 ping statistics ---
5 packet(s) transmitted
5 packet(s) received
0.00% packet loss
round-trip min/avg/max = 1/41/205 ms
The output shows that Device A sends five ICMP packets to Device C and Device A receives five
ICMP packets. The route is reachable.
# Get detailed information about routes from DeviceA to Device C.
<DeviceA> ping -r 1.1.2.2
PING 1.1.2.2: 56 data bytes, press CTRL_C to break
Reply from 1.1.2.2: bytes=56 Sequence=1 ttl=254 time=53 ms
Record Route:
1.1.2.1
1.1.2.2
1.1.1.2
1.1.1.1
Reply from 1.1.2.2: bytes=56 Sequence=2 ttl=254 time=1 ms
Record Route:
1.1.2.1
1.1.2.2
1.1.1.2
1.1.1.1
Reply from 1.1.2.2: bytes=56 Sequence=3 ttl=254 time=1 ms
Record Route:
1.1.2.1
1.1.2.2

3
1.1.1.2
1.1.1.1
Reply from 1.1.2.2: bytes=56 Sequence=4 ttl=254 time=1 ms
Record Route:
1.1.2.1
1.1.2.2
1.1.1.2
1.1.1.1
Reply from 1.1.2.2: bytes=56 Sequence=5 ttl=254 time=1 ms
Record Route:
1.1.2.1
1.1.2.2
1.1.1.2
1.1.1.1
--- 1.1.2.2 ping statistics ---
5 packet(s) transmitted
5 packet(s) received
0.00% packet loss
round-trip min/avg/max = 1/11/53 ms
The test procedure with the ping –r command (see Figure 1) is as follows:
1. The source device (Device A) sends an ICMP echo request with the RR option being empty to
the destination device (Device C).
2. The intermediate device (Device B) adds the IP address of its outbound interface (1.1.2.1) to
the RR option of the ICMP echo request, and forwards the packet.
3. Upon receiving the request, the destination device copies the RR option in the request and
adds the IP address of its outbound interface (1.1.2.2) to the RR option. Then the destination
device sends an ICMP echo reply.
4. The intermediate device adds the IP address of its outbound interface (1.1.1.2) to the RR option
in the ICMP echo reply, and then forwards the reply.
5. Upon receiving the reply, the source device adds the IP address of its inbound interface (1.1.1.1)
to the RR option. Finally, you can get detailed information about routes from Device A to Device
C: 1.1.1.1 <-> {1.1.1.2; 1.1.2.1} <-> 1.1.2.2.
Tracert
Tracert (also called "Traceroute") enables you to get the IP addresses of Layer 3 devices in the path
to a specific destination. You can use tracert to test network connectivity and identify the failed
nodes.

4
Figure 2 Traceroute operation
Tracert uses received ICMP error messages to get the IP addresses of devices.As shown in Figure
2, tracert works as follows:
1. The source device (Device A) sends a UDP packet with a TTL value of 1 to the destination
device (Device D). The destination UDP port is not used by any application on the destination
device.
2. The first hop (Device B, the first Layer 3 device that receives the packet) responds by sending a
TTL-expired ICMP error message to the source, with its IP address (1.1.1.2) encapsulated. In
this way, the source device can get the address of the first Layer 3 device (1.1.1.2).
3. The source device sends a packet with a TTL value of 2 to the destination device.
4. The second hop (Device C) responds with a TTL-expired ICMP error message, which gives the
source device the address of the second Layer 3 device (1.1.2.2).
5. This process continues until the packet sent by the source device reaches the ultimate
destination device. Because no application uses the destination port specified in the packet, the
destination device responds with a port-unreachable ICMP message to the source device, with
its IP address encapsulated. This way, the source device gets the IP address of the destination
device (1.1.3.2).
6. The source device thinks that the packet has reached the destination device after receiving the
port-unreachable ICMP message, and the path to the destination device is 1.1.1.2 to 1.1.2.2 to
1.1.3.2.
Prerequisites
Before you use a tracert command, perform the tasks in this section.
For an IPv4 network:
•Enable sending of ICMP timeout packets on the intermediate devices (devices between the
source and destination devices). If the intermediate devices are HPE devices, execute the ip
ttl-expires enable command on the devices. For more information about this command, see
Layer 3—IP Services Command Reference.
•Enable sending of ICMP destination unreachable packets on the destination device. If the
destination device is an HPE device, execute the ip unreachables enable command. For more
information about this command, see Layer 3—IP Services Command Reference.
•If there is an MPLS network between the source and destination devices and you need to
display the MPLS information during the tracert process, enable support for ICMP extensions
on the source and intermediate devices. If the source and intermediate devices are HPE
devices, execute the ip icmp-extensions compliant command on the devices. For more
information about this command, see Layer 3—IP Services Command Reference.

5
For an IPv6 network:
•Enable sending of ICMPv6 timeout packets on the intermediate devices (devices between the
source and destination devices). If the intermediate devices are HPE devices, execute the ipv6
hoplimit-expires enable command on the devices. For more information about this command,
see Layer 3—IP Services Command Reference.
•Enable sending of ICMPv6 destination unreachable packets on the destination device. If the
destination device is an HPE device, execute the ipv6 unreachables enable command. For
more information about this command, see Layer 3—IP Services Command Reference.
Using a tracert command to identify failed or all nodes in a
path
Task Command Remarks
Display the routes from source
to destination.
•For IPv4 networks:
tracert [ -a source-ip | -f first-ttl |
-m max-ttl | -p port | -q
packet-number | -tos tos |
-vpn-instance
vpn-instance-name | -w timeout ] *
host
•For IPv6 networks:
tracert ipv6 [ -a source-ipv6 | -f
first-ttl | -m max-ttl | -p port | -q
packet-number | -tos tos |
-vpn-instance
vpn-instance-name | -w timeout ] *
host
Use either approach.
Available in any view.
For more information about the tracert lsp command, see MPLS Command Reference.
System debugging
The device supports debugging for the majority of supported protocols and features and provides
debugging information to help users diagnose errors.
Debugging information control switches
The following switches control the display of debugging information:
•Protocol debugging switch—Controls whether to generate the protocol-specific debugging
information.
•Screen output switch—Controls whether to display the debugging information on a certain
screen.
As shown in Figure 3, assume the device can provide debugging for the three modules 1, 2, and 3.
The debugging information can be output on a terminal only when both the protocol-debugging
switch and the screen-output switch are turned on.
Output of debugging information depends on the configurations of the information center and the
debugging commands of each protocol and functional module. Debugging information is typically
displayed on a console. You can also send debugging information to other destinations. For more
information, see "Configuring the information center."

6
Figure 3 Relationship between the protocol-debugging switch and screen-output switch
Debugging a feature module
Output of debugging commands is memory intensive. To guarantee system performance, enable
debugging only for modules that are in an exceptional condition. When debugging is complete, use
the undo debugging all command to disable all the debugging functions.
To debug a feature module and display the debugging information on a terminal:
Step Command Remarks
1. Enable the terminal
monitoring of system
information. terminal monitor
Optional.
By default, the terminal
monitoring on the console port is
enabled and that on the
monitoring terminal is disabled.
Available in user view.
2. Enable the terminal to
display debugging
information. terminal debugging
By default, terminal display of
debugging information is
disabled.
Available in user view.
3. Enable debugging for a
specific feature module. debugging { all [ timeout time ] |
module-name [ option ] }
By default, debugging for a
specified module is disabled.
Available in user view.
4. Display the enabled
debugging functions.
display debugging [ interface
interface-type interface-number ]
[module-name ] [ | { begin |
exclude | include }
regular-expression ]
Optional.
Available in any view.
NOTE:
You must configure the debugging,terminal debugging and terminal monitor commands before
you can display the detailed debugging information on the terminal. For more information about the
terminal debugging and terminal monitor commands, see Network Management and Monitorin
g
Command Reference.

7
Ping and tracert example
Network requirements
As shown in Figure 4, Device Afailed to Telnet to Device C. Determine whether DeviceAand Device
C can reach each other. If they cannot reach each other, locate the failed nodes in the network.
Figure 4 Network diagram
Test procedure
1. Use the ping command to test connectivity between Device A and Device C.
<DeviceA> ping 1.1.2.2
PING 1.1.2.2: 56 data bytes, press CTRL_C to break
Request time out
Request time out
Request time out
Request time out
Request time out
--- 1.1.2.2 ping statistics ---
5 packet(s) transmitted
0 packet(s) received
100.00% packet loss
The output shows that Device A and Device C cannot reach each other.
2. Use the tracert command to identify failed nodes:
# Enable sending of ICMP timeout packets on Device B.
<DeviceB> system-view
[DeviceB] ip ttl-expires enable
# Enable sending of ICMP destination unreachable packets on Device C.
<DeviceC> system-view
[DeviceC] ip unreachables enable
# Execute the tracert command on DeviceA.
<DeviceA> tracert 1.1.2.2
traceroute to 1.1.2.2(1.1.2.2) 30 hops max,40 bytes packet, press CTRL_C to break
1 1.1.1.2 14 ms 10 ms 20 ms
2 * * *
3 * * *
4 * * *
5
<DeviceA>
The output shows that Device A and Device C cannot reach other, that Device A and Device B
can reach each other, and that an error occurred on the connection between Device B and
Device C.

8
3. Use the debugging ip icmp command on Device A and Device C to verify that they can send
and receive the specific ICMP packets, or use the display ip routing-table command to verify
the availability of active routes between Device A and Device C.

9
Configuring NTP
This chapter provides an overview of NTP configuration.
Overview
NTP is typically used in large networks to dynamically synchronize time among network devices. It
guarantees higher clock accuracy than manual system clock setting. In a small network that does not
require high clock accuracy, you can keep time synchronized among devices by changing their
system clocks one by one.
NTP runs over UDP and uses UDP port 123.
NTP application
An administrator is unable to keep time synchronized among all devices within a network by
changing the system clock on each station, because this is a huge work and does not guarantee
clock precision. NTP, however, allows quick clock synchronization within the entire network and
ensures high clock precision.
NTP is used when all devices within the network must keep consistent time. For example:
•In analyzing log and debugging information collected from different devices in network
management, time must be used as a reference basis.
•All devices must use the same reference clock in a charging system.
•To implement certain functions, such as a scheduled restart of all devices within the network, all
devices must keep consistent time.
•If multiple systems process a complex event in cooperation, these systems must use the same
reference clock to ensure the correct execution sequence.
•For incremental backup between a backup server and clients, timekeeping must be
synchronized between the backup server and all clients.
NTP advantages
•NTP uses a stratum to describe clock accuracy. The stratum ranges from 1 to 16. Clock
accuracy decreases as the stratum number increases. The stratum of a reference clock ranges
from 1 to 15. A stratum 16 clock is in unsynchronized state.
•NTP supports access control and MD5 authentication.
•NTP can unicast, multicast, or broadcast protocol messages.
How NTP works
Figure 5 shows the basic workflow of NTP. Device A and Device B are connected over a network.
They have their own independent system clocks, which need to be automatically synchronized
through NTP. Assume that:
•Prior to system clock synchronization between Device A and Device B, the clock of Device Ais
set to 10:00:00 am while that of Device B is set to 11:00:00 am.
•Device B is used as the NTP time server, so Device A synchronizes to Device B.
•It takes 1 second for an NTP message to travel from one device to the other.

10
Figure 5 Basic work flow of NTP
The synchronization process is as follows:
•Device Asends Device B an NTP message, which is timestamped when it leaves Device A. The
timestamp is 10:00:00 am (T1).
•When this NTP message arrives at Device B, it is timestamped by Device B. The timestamp is
11:00:01 am (T2).
•When the NTP message leaves Device B, Device B timestamps it. The timestamp is 11:00:02
am (T3).
•When DeviceA receives the NTP message, the local time of Device Ais 10:00:03 am (T4).
Up to now, Device A can calculate the following parameters based on the timestamps:
•The roundtrip delay of NTP message: Delay = (T4–T1) – (T3-T2) = 2 seconds.
•Time difference between Device Aand Device B: Offset = ((T2-T1) + (T3-T4))/2 = 1 hour.
Based on these parameters, DeviceA can synchronize its own clock to the clock of Device B.
This is a rough description of how NTP works. For more information, see RFC 1305.
NTP message format
NTP uses two types of messages: clock synchronization and NTP control messages. All NTP
messages mentioned in this document refer to NTP clock synchronization messages. NTP control
messages are used in environments where network management is needed. Because NTP control
messages are not essential for clock synchronization, they are not described in this document.
A clock synchronization message is encapsulated in a UDP message in the format shown in Figure
6.

11
Figure 6 Clock synchronization message format
The main fields are described as follows:
•LI (Leap Indicator)—A 2-bit leap indicator. If set to 11, it warns of an alarm condition (clock
unsynchronized). If set to any other value, it is not to be processed by NTP.
•VN (Version Number)—A3-bit version number that indicates the version of NTP. The latest
version is version 4.
•Mode—A 3-bit code that indicates the operation mode of NTP. This field can be set to these
values:
{0—Reserved.
{1—Symmetric active.
{2—Symmetric passive.
{3—Client.
{4—Server.
{5—Broadcast or multicast.
{6—NTP control message.
{7—Reserved for private use.
•Stratum—An 8-bit integer that indicates the stratum level of the local clock, with the value
ranging from 1 to 16. Clock precision decreases from stratum 1 through stratum 16.Astratum 1
clock has the highest precision, and a stratum 16 clock is not synchronized.
•Poll—An 8-bit signed integer that indicates the maximum interval between successive
messages, which is called the poll interval.
•Precision—An 8-bit signed integer that indicates the precision of the local clock.
•Root Delay—Roundtrip delay to the primary reference source.
•Root Dispersion—The maximum error of the local clock relative to the primary reference
source.
•Reference Identifier—Identifier of the particular reference source.
•Reference Timestamp—The local time at which the local clock was last set or corrected.