RA general operation

An IPv6 routing switch configured as a member of a given VLAN transmits RAs for use by hosts on the VLAN. It also transmits unscheduled RAs in response to router solicitations received from IPv6 hosts on the VLAN. The values a host receives in an RA are applied to settings that have not already been configured on the host by the system operator. (Values in an RA can also replace host settings that were learned from a previous RA.)

When IPv6 unicast routing is enabled, RAs are transmitted by default on VLANs enabled for IPv6 and configured with an IPv6 link-local address, unless RA transmission has been explicitly suppressed. RA configuration includes:

Advertisement Value	Default	Page
managed flag (M-bit)	Not set	VLAN context Neighbor Discovery (ND) configuration
other-config-flag (O-bit)	Not set	VLAN context Neighbor Discovery (ND) configuration
prefix	The prefix of any global unicast IPv6 address configured on the VLAN interface¹	Configuring the global unicast prefix and lifetime for hosts on a VLAN
length	N/A; based on existing configuration	—
valid lifetime	2,592,000 seconds (30 days)	—
preferred lifetime	604,800 seconds (seven days)	—
autoconfig (A-bit)	Set (host autoconfig enabled)	—
on-link (L-bit)	Set (use prefix on subject VLAN)	—
RA transmission interval		—
maximum	600 seconds	Configuring the range for intervals between RA transmissions on a VLAN
minimum	200 seconds	Configuring the range for intervals between RA transmissions on a VLAN
current hop limit	64	Setting or changing the hop-limit for host-generated packets
default lifetime	1800 seconds (3 x max. transmission interval)	Setting or changing the default router lifetime
reachable time	Unspecified (0)	Changing the reachable time duration for neighbors
retransmission timer	Unspecified (0)	Setting or changing the neighbor discovery retransmit timer

Default operation excludes prefixes of stateless autoconfigured addresses.