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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter39 Configuring IPv6 Unicast Routing
Configuring IPv6
Switch# show ipv6 interface gigabitethernet1/0/1
GigabitEthernet1/0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::20B:46FF:FE2F:D940
Global unicast address(es):
2001:0DB8:c18:1:20B:46FF:FE2F:D940, subnet is 2001:0DB8:c18:1::/64 [EUI]
Joined group address(es):
FF02::1
FF02::2
FF02::1:FF2F:D940
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds
ND advertised reachable time is 0 milliseconds
ND advertised retransmit interval is 0 milliseconds
ND router advertisements are sent every 200 seconds
ND router advertisements live for 1800 seconds
Hosts use stateless autoconfig for addresses.
Configuring Default Router Preference
Router advertisement messages are sent with the default router preference (DRP) configured by the
ipv6 nd router-preference interface configuration command. If no DRP is configured, RAs are sent
with a medium preference.
A DRP is useful when two routers on a link might provide equivalent, but not equal-cost routing, and
policy might dictate that hosts should prefer one of the routers.
Beginning in privileged EXEC mode, follow these steps to configure a DRP for a router on an interface.
Use the no ipv6 nd router-preference interface configuration command to disable an IPv6 DRP.
This example shows how to configure a DRP of high for the router on an interface.
Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ipv6 nd router-preference high
Switch(config-if)# end
For more information about configuring DRP for IPv6, see the “Implementing IPv6 Addresses and Basic
Connectivity” chapter in the Cisco IOS IPv6 Configuration Library on Cisco.com.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and enter the Layer3 interface on
which you want to specify the DRP.
Step3 ipv6 nd router-preference {high |
medium | low}
Specify a DRP for the router on the switch interface.
Step4 end Return to privileged EXEC mode.
Step5 show ipv6 interface Verify the configuration.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.