3Com Switch 8800 Configuration Guide Chapter 46 System Maintenance and Debugging
46-6
46.4.3 tracert
The tracert is used for testing the gateways passed by the packets from the source
host to the destination one. It is mainly used for checking if the network is connected
and analyzing where the fault occurs in the network.
The execution process of tracert is described as follows: Send a packet with TTL value
as 1 and the first hop sends back an ICMP error message indicating that the packet
cannot be sent, for the TTL is timeout. Re-send the packet with TTL value as 2 and the
second hop returns the TTL timeout message. The process is carried over and over
until the packet reaches the destination. The purpose to carry out the process is to
record the source address of each ICMP TTL timeout message, so as to provide the
route of an IP packet to the destination.
Perform the following configuration in any view.
Table 46-10 The tracert command
Operation Command
Trace route tracert [ -a source-IP | -f first-TTL | -m max-TTL | -p port |
-q num-packet | -vpn-instance vpn-instance-name | -w
timeout ] string
46.5.1 Introduction to Info-center
The Info-center is an indispensable part of the Ethernet switch. It serves as an
information center of the system software modules. The logging system is responsible
for most of the information outputs, and it also makes detailed classification to filter the
information efficiently. Coupled with the debugging program, the info-center provides
powerful support for the network administrators and the R&D personnel to monitor the
operating state of networks and diagnose network failures.
When the log information is output to terminal or log buffer, the following parts will be
included:
% <priority> Timestamp Sysname Module name/Severity/Digest: Content
For example:
%Jun 7 05:22:03 2003 SW8800 IFNET/6/UPDOWN:Line protocol on interface
Ethernet2/1/2, changed state to UP
When the log information is output to info-center, the first part will be “<Priority>”.
For example:
% <189>Jun 7 05:22:03 2003 SW8800 IFNET/6/UPDOWN:Line protocol on interface
Ethernet0/0/0, changed state to UP