3Com 10014298 Configure Whether to Forward L3 Broadcast Packets, Display and Debug IP Performance

78CHAPTER 4: NETWORK PROTOCOL OPERATION

operation, you may have to use the following commands to prevent the corresponding packets from being sent to the CPU.

Perform the following configuration in system view.

Table 75 Configure Whether to Send Special IP Packets to CPU

Operation	Command
Configure the system to send packets to the	ip { redirects		ttl-expires
CPU	unreachables }
Configure the system not to send packets to	undo ip { redirects ttl-expires
the CPU	unreachables	}

By default, redirection packets and route unreachable packets are not sent to CPU, while TTL timeout packets are sent to CPU.

Configuring L3 Broadcast packets include full-net broadcast packets and direct-connected Broadcast Forwarding broadcast packets. The destination IP address of a full-net broadcast packet is all

ones (255.255.255.255) or all zeros. A direct-connected broadcast packet is a packet whose destination IP address is the network broadcast address of a subnet, but the source IP address is not in the subnet segment. When a switch forwards a packet, it cannot tell whether the packet is a broadcast packet unless the switch is connected with the subnet.

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.

Table 76 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

By default, L3 broadcast packets are forwarded.

Displaying and After the previous configuration, display the operation of the IP Performance Debugging IP configuration in all views, and verify the effect of the configuration. Execute the Performance debugging command in user view to debug IP Performance configuration.

Table 77 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