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
1

Default operation excludes prefixes of stateless autoconfigured addresses.