User's Manual
393
Chapter 53 Chapter 3 IP Service
Configuration
The section is to describe how to configure optional IP service. For the details of the IP service commands,
refer to section “IP Service Commands”.
53.1 Configuring IP Service
Optional IP service configuration tasks are listed as follows:
Managing IP connection
Configuring performance parameters
Configuring default gateway
Detecting and Maintaining IP Network
The above operations are not mandatory. You can perform the operations according to your requirements.
53.1.1 Managing IP Connection
The IP protocol provides a series of services to control and manage IP connections. Most of these services
are provided by ICMP. The ICMP message is sent to the host or other routing SWITCH when the routing
SWITCH or the access server detects faults in the IP message header. ICMP is mainly defined in RFC 792.
Perform the following different operations according to different IP connection conditions:
(1) Sending ICMP Unreachable Message
If the system receives a message and cannot send it to the destination, such as no routes, the system will
send an ICMP-unreachable message to the source host. The function of the system is enabled by default.
If the function is disabled, you can run the following command in VLAN interface configuration mode to enable
the function.
Command Purpose
ip unreachables
Enable the function to send an ICMP-
unreachable message.
(2) Sending ICMP Redirection Message
Sometimes the host selects an unfavorable route. After a routing SWITCH on the route receives a message
from the host, it is to check the routing table and then forward the message through the message-receiving
interface to another SWITCH that is in the same network segment as the host. In this case, the SWITCH
notifies the source host of directly sending the message with the destination to another SWITCH without
winding itself. The redirection message requires the source host to discard the original route and take more
direct route suggested in the message. Many host’s operating system adds a host route to its routing table.
However, the routing SWITCH is more willing to trust information obtained through the routing protocol.
Therefore, the SWITCH will not add the host route according to the information.
The function is enabled by default. However, if a hot standby SWITCH protocol is configured on an interface,
IPv6 redirection is automatically closed. If the hot standby SWITCH protocol is canceled, this function will not