HP 5500 Ei 5500 Si Switch Series Configuration Guide

 
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Using ping, tracert, and system debugging 
Use the ping, tracert, and system debugging utilitie s 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...

 
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Figure 1  Network diagram 
 
 
Test procedure 
# Use the ping command on Device A to test connectivity to Device C. 
 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...

 
3 
         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...

 
4 
Figure 2  Network diagram 
 
 
Tracert uses received ICMP error messages to get the IP addresses of devices. As shown in Figure 2, 
tr
acert 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...

 
5 
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 unreacha ble packets on the destination device. If the 
destination device is an HP 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...

 
6 
Figure 3  Relationship between the protocol 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 exceptio nal condition. When debugging is complete, use the 
undo debugging all  command to disable all the debugging functions. 
Configure the  debugging, terminal debugging , and terminal monitor commands before you can display 
detailed debugging information on the...

 
7 
Ping and tracert example 
Network requirements 
As shown in  Figure 4, Device A failed to Telnet Device C. Determine whether Device A and 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. 
 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...

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Configuring NTP 
The term Layer 3 Ethernet port  refers to route-mode (or Layer 3) Ethernet ports. You can set an Ethernet 
port to operate in route mode by using the  port link-mode  route  command (see  Layer 2—LAN Switching 
Configuration Guide ). 
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...

 9 
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 A is set 
to 10:00:00 am while that of Device B is set to 1 1:00:00 am. 
•   Device B is used as the NTP time server, so Device A synchronizes to Device B. 
•   It takes 1 second for...