Technical data

70 CHAPTER 4: NETWORK PROTOCOL OPERATION
If a broadcast packet reaches the destination network after being forwarded by
the switch, the switch will receive the broadcast packet; the switch also belongs to
the subnet. The VLAN of the switch isolates the broadcast domain, it will stop
forwarding the packet to the network. Using the following configuration task, you
can choose to forward the broadcast packet to the network for broadcasting.
Perform the following configuration in system view.
By default, L3 broadcast packets is forwarded.
Displaying and
Debugging IP
Performance
After the previous configuration, display the operation of the IP Performance
configuration in all views, and verify the effect of the configuration. Execute the
debugging command in user view to debug IP Performance configuration.
Troubleshooting IP
Performance
If the IP layer protocol works normally, but TCP and UDP do not work normally,
you can enable the corresponding debugging information output to view the
debugging information.
■ Use the terminal debugging command to output the debugging information
to the console.
■ Use the debugging udp packet command to enable the UDP debugging to
trace the UDP packet. When the router sends or receives UDP packets, the
content format of the packet can be displayed in real time. You can locate the
problem from the contents of the packet.
The following are the UDP packet formats:
UDP output packet:
Source IP address:202.38.160.1
Source port:1024
Destination IP Address 202.38.160.1
Destination port: 4296
■ Use the debugging tcp packet or debugging tcp transaction command to
enable the TCP debugging to trace the TCP packets. There are two available
ways for debugging TCP.
■ Debug and trace the packets of the TCP connection that take this device as one
end.
Tab le 15 Configure Whether to Forward L3 Broadcast Packets
Operation Command
Configure forward L3 broadcast packets ip forward-broadcast
Disable forward L3 broadcast packets undo ip forward-broadcast
Tab le 16 Display and Debug IP Performance
Operation Command
Display TCP connection state display tcp status
Display TCP connection statistics data display tcp statistics
Display IP statistics information display ip statistics
Display ICMP statistics information display icmp statistics
Reset IP statistics information reset ip statistics
Reset TCP statistics information reset tcp statistics