Configuring Special Ip Packet Transmission To The Cpu; Configuring L3 Broadcast Forwarding - 3Com Switch 7700 Configuration Manual

Configuring Special IP
Packet Transmission to
the CPU
Configuring L3
Broadcast Forwarding
finwait timer timeout, the TCP connection will be terminated. Finwait ranges
76 to 3600 seconds and it is 675 seconds by default.
The receiving/sending buffer size of connection-oriented Socket is in the range
■
from 1 to 32K bytes and is 4K bytes by default.
Perform the following configuration in System view.
Table 13 Configure TCP Attributes
Operation
Configure synwait timer time for TCP
connection establishment
Restore synwait timer time for TCP connection
establishment to default value
Configure FIN_WAIT_2 timer time of TCP
Restore FIN_WAIT_2 timer time of TCP to
default value
Configure the Socket receiving/sending buffer
size of TCP
Restore the socket receiving/sending buffer
size of TCP to default value
By default, the TCP finwait timer is 675 seconds, the synwait timer is 75 seconds,
and the receiving/sending buffer size of connection-oriented Socket is 4K bytes.
In IP packet forwarding, redirection packets, TTL timeout packets, and route
unreachable packets are often sent to CPU, which will notify the peer end for
further processing upon receiving them, but configuration errors and malicious
assaults may cause CPU overload. In this case, to maintain normal system
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.
Configure Whether to Send Special IP Packets to CPU
Table 14
Operation
Configure the system to send packets to the
CPU
Configure the system not to send packets to
the CPU
By default, redirection packets and route unreachable packets are not sent to CPU,
while, TTL timeout packets are sent to CPU.
Broadcast packets include full-net broadcast packets and direct-connected
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.
IP Performance
Command
tcp timer syn-timeout time-value
undo tcp timer syn-timeout
tcp timer fin-timeout time-value
undo tcp timer fin-timeout
tcp window window-size
undo tcp window
Command
ip { redirects | ttl-expires | unreachables }
undo ip { redirects | ttl-expires |
unreachables }
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