H3C S5120-EI Series User Manual

1-13
Configuring Parameters Related to RA Messages
You can enable an interface to send RA messages, and configure the interval for sending RA messages
and parameters in RA messages. After receiving an RA message, a host can use these parameters to
perform corresponding operations.
Table 1-4 lists the configurable parameters in an RA message and
their descriptions.
Table 1-4 Parameters in an RA message and their descriptions
Parameters Description
Cur hop limit
When sending an IPv6 packet, a host uses the value to fill the Cur Hop Limit
field in IPv6 headers. The value is also filled into the Cur Hop Limit field in
response messages of a device.
Prefix information
options
After receiving the prefix information advertised by the device, the hosts on
the same link can perform stateless autoconfiguration.
M flag
This field determines whether hosts use the stateful autoconfiguration to
acquire IPv6 addresses.
If the M flag is set to 1, hosts use the stateful autoconfiguration to acquire
IPv6 addresses (for example, through a DHCP server). Otherwise, hosts
use the stateless autoconfiguration to acquire IPv6 addresses, that is,
hosts generate IPv6 addresses according to their own link-layer addresses
and the prefix information issued by the router.
O flag
This field determines whether hosts use the stateful autoconfiguration to
acquire information other than IPv6 addresses.
If the O flag is set to 1, hosts use the stateful autoconfiguration to acquire
information other than IPv6 addresses (for example, through a DHCP
server). Otherwise, hosts use the stateless autoconfiguration to acquire
information other than IPv6 addresses.
Router lifetime
This field is used to set the lifetime of the router that sends RA messages to
serve as the default router of hosts. According to the router lifetime in the
received RA messages, hosts determine whether the router sending RA
messages can serve as the default router.
Retrans timer
If the device fails to receive a response message within the specified time
after sending an NS message, the device will retransmit the NS message.
Reachable time
If the neighbor reachability detection shows that a neighbor is reachable,
the device considers the neighbor reachable within the specified reachable
time. If the device needs to send a packet to a neighbor after the specified
reachable time expires, the device will reconfirm whether the neighbor is
reachable.
The values of the Retrans Timer and the Reachable Time configured for an interface are sent to hosts
via RA messages. Furthermore, this interface sends NS messages at the interval of Retrans Timer and
considers a neighbor reachable within the Reachable Time.
Follow these steps to configure parameters related to an RA message:
To do… Use the command… Remarks
Enter system view
system-view
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H3C S5120-EI Series Specifications

General

Brand	H3C
Model	S5120-EI Series
Category	Switch
Language	English