Reference Guide

Prex advertisement Routers use router advertisement messages to advertise the network prex. Hosts append their interface-identier
MAC address to generate a valid IPv6 address.
Duplicate address
detection
An IPv6 host node checks whether that address is used anywhere on the network using this mechanism before
conguring its IPv6 address.
Prex renumbering Transparent renumbering of hosts in the network when an organization changes its service provider.
IPv6 provides the exibility to add prexes on router advertisements in response to a router solicitation (RS). By default, RA response
messages are sent when an RS message is received. The system manipulation of IPv6 stateless autoconguration supports the router side
only. Neighbor Discovery (ND) messages advertise so the neighbor can use the information to auto-congure its address. Received ND
messages are not used to create an IPv6 address.
Inconsistencies in router advertisement values between routers are logged. The values checked for consistency include:
• Current hop limit
• M and O ags
• Reachable time
• Retransmission timer
• MTU options
• Preferred and valid lifetime values for the same prex
The router redirect functionality in the NDP is similar to IPv4 router redirect messages. NDP uses ICMPv6 redirect messages (Type 137) to
inform nodes that a better router exists on the link.
Neighbor Discovery
The IPv6 NDP determines if neighboring IPv6 devices are reachable and receives the IPv6 addresses of IPv6 devices on local links. Using
the link-layer and global prexes of neighbor addresses, OS10 performs stateless autoconguration of IPv6 addresses on interfaces.
ICMPv6 Router Advertisement messages advertise the IPv6 addresses of IPv6-enabled interfaces and allow a router to learn of any
address changes in IPv6 neighbors. By default, router advertisements are disabled on an interface.
Prerequisites
To enable RA messages, the switch must be in Router mode with IPv6 forwarding enabled and stateless autoconguration disabled (no
ipv6 address autoconfig
command).
Enable router advertisement messages
1 Enable IPv6 neighbor discovery and sending ICMPv6 RA messages in Interface mode.
ipv6 nd send-ra
2 (Optional) Congure IPv6 neighbor discovery options in Interface mode.
• ipv6 nd hop-limit hops — (Optional) Sets the hop limit advertised in RA messages and included in IPv6 data packets
sent by the router (0 to 255; default 64). 0 indicates that no hop limit is specied by the router.
• ipv6 nd managed-config-flag — (Optional) Sent in RA messages to tell hosts to use stateful address autoconguration,
such as DHCPv6, to obtain IPv6 addresses.
• ipv6 nd max-ra-interval seconds — (Optional) Sets the maximum time interval for sending RA messages (4 to 1800
seconds; default 600).
• ipv6 nd mtu number — (Optional) Sets the maximum transmission unit (MTU) used in RA messages on the link (1280 to
65535 bytes; default 1500). By default, no MTU setting is included in RA messages.
• ipv6 nd other-config-flag — (Optional) Tells hosts to use stateful autoconguration to obtain nonaddress-related
information.
• ipv6 nd ra-lifetime seconds — (Optional) Sets the lifetime of a default router in RA messages (0 to 9000 milliseconds;
default 3 times the
max-ra-interval setting). 0 indicates that this router is not used as a default router.
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Layer 3