Reference Guide

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 Neighbor Discovery protocol (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 Neighbor Discovery protocol (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.
• ipv6 nd reachable-time milliseconds — (Optional) Sets the advertised time for which the router sees that a
neighbor is up after it receives neighbor reachability conrmation (0 to 3600000 milliseconds; default 0).
0 indicates that no
reachable time is sent in RA messages.
• ipv6 nd retrans-timer seconds — (Optional) Sets the time between retransmitting neighbor solicitation messages (100
to 4292967295 milliseconds). By default, no retransmit timer is congured.
Layer 3
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