Technical Documentation
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Monitoring Received IPv6 Router Advertisements
Purpose
Display IPv6 router advertisement information received. You can use the conflicts keyword to display router advertisements that differ from the advertisements configured.
Action
To display IPv6 router advertisement information received:
host1#show ipv6 routers
Router FE80::83B3:60A4 on FastEthernet2/0, last update 3 min
Hops 0, Lifetime 6000 sec, AddrFlag=0, OtherFlag=0
Reachable time 0 msec, Retransmit time 0 msec
Prefix 3FFE:C00:8007::800:207C:4E37/96 autoconfig
Valid lifetime -1, preferred lifetime -1Router FE80::290:27FF:FE8C:B709 on FastEthernet2/1, last update 0 min Hops 64, Lifetime 1800 sec, AddrFlag=0, OtherFlag=0 Reachable time 0 msec, Retransmit time 0 msec
To display router advertisements that differ from the advertisements configured:
host1#show ipv6 routers conflicts
Router FE80::203:FDFF:FE34:7039 on FastEthernet1/0, last update 1 min, CONFLICT
Hops 64, Lifetime 1800 sec, AddrFlag=0, OtherFlag=0
Reachable time 0 msec, Retransmit time 0 msec
Prefix 2003::/64 onlink autoconfig
Valid lifetime -1, preferred lifetime -1Meaning
Table 1 lists the show ipv6 routers command output fields.
Table 1: show ipv6 routers Output Fields
Field Name | Field Description |
|---|---|
Router | Router for which this information applies |
Hops | Number of hops that the router uses in router advertisements |
Lifetime | Lifetime (in seconds) of the neighbor discovery router advertisement |
AddrFlag | State of the neighbor discovery router advertisement managed flag |
OtherFlag | State of the neighbor discovery router advertisement other config flag |
Reachable time | Amount of time (in milliseconds) that the neighbor is expected to remain reachable |
Retransmit time | Interval in which the router retransmits neighbor solicitations |
Prefix | IPv6 network number to include in router advertisements |
Autoconfig | When present, indicates that local host links use the specified prefix for IPv6 autoconfiguration |
Valid lifetime | Amount of time in seconds that the router advertises the IPv6 prefix as valid |
preferred lifetime | Amount of time in seconds that the router advertises the specified IPv6 prefix as preferred |
