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You can enable an interface to send RA messages, specify the maximum and minimum sending
intervals, and configure parameters in RA messages. The device sends RA messages at random
intervals between the maximum and minimum intervals. The minimum interval should be less than or
equal to 0.75 times the maximum interval.
describes the configurable parameters in an RA message.
Table 14 Parameters in an RA message and their descriptions
Parameter Description
IPv6 prefix/prefix length
The IPv6 prefix/prefix length for a host to generate an IPv6 global unicast
address through stateless autoconfiguration.
Valid lifetime
Specifies the valid lifetime of a prefix. The generated IPv6 address is valid
within the valid lifetime and becomes invalid when the valid lifetime
expires.
Preferred lifetime
Specifies the preferred lifetime of a prefix used for stateless
autoconfiguration. After the preferred lifetime expires, the node cannot use
the generated IPv6 address to establish new connections, but can receive
packets destined for the IPv6 address. The preferred lifetime cannot be
greater than the valid lifetime.
No-autoconfig flag
Tells the hosts not to use the address prefix for stateless
autoconfiguration.
Off-link flag
Specifies the address with the prefix to be indirectly reachable on the link.
MTU
Guarantees that all nodes on the link use the same MTU.
Unlimited hops flag
Specifies unlimited hops in RA messages.
M flag
Determines whether a host uses stateful autoconfiguration to obtain an
IPv6 address.
If the M flag is set, the host uses stateful autoconfiguration (for example,
from a DHCPv6 server) to obtain an IPv6 address. If the flag is not set, the
host uses stateless autoconfiguration to generate an IPv6 address
according to its link-layer address and the prefix information in the RA
message.
O flag
Determines whether a host uses stateful autoconfiguration to obtain
configuration information other than IPv6 address.
If the O flag is set, the host uses stateful autoconfiguration (for example,
from a DHCPv6 server) to obtain configuration information other than IPv6
address. If the flag is not set, the host uses stateless autoconfiguration.
Router Lifetime
Advertises the lifetime of an advertising router. If the lifetime is 0, the router
cannot be used as the default gateway.
Retrans Timer
Specifies the interval for retransmitting the NS message after the device
does not receive a response for an NS message within a time period.
Router Preference
Specifies the router preference in an RA message. A host selects a router
as the default gateway according to the router preference. If router
preferences are the same, the host selects the router from which the first
RA message is received.
Reachable Time
Specifies the reachable period for a neighbor after the device detects that
a neighbor is reachable. If the device needs to send a packet to the
neighbor after the reachable period, the device reconfirms whether the
neighbor is reachable.
