off-link (OPTIONAL) Enter the keywords off-link to not use prefixes for 
on-link determination.
Defaults Not configured.
Command Modes INTERFACE
Usage 
Information
The description of an IPv6 prefix from RFC 2461(http://tools.ietf.org/html/rfc2461) is a bit string 
that consists of some number of initial bits of an address.
ipv6 nd ra-lifetime
Configure the router lifetime value in the IPv6 router advertisements on an interface.
E-Series
Syntax
ipv6 nd ra-lifetime seconds
To restore the default values, use the no ipv6 nd ra-lifetime command.
Parameters
seconds
Enter the lifetime value in seconds. The range is 0 to 9000.
Defaults 9000 seconds
Command Modes INTERFACE
Usage 
Information
The description of router lifetime from RFC 2461(http://tools.ietf.org/html/rfc2461) is:
Router Lifetime: 16-bit unsigned integer. The lifetime associated with the default router in units 
of seconds. The maximum value corresponds to 18.2 hours. A Lifetime of 0 indicates that the 
router is not a default router and SHOULD NOT appear on the default router list. The Router 
Lifetime applies only to the router's usefulness as a default router; it does not apply to 
information contained in other message fields or options. Options that need time limits for their 
information include their own lifetime fields.
ipv6 nd reachable-time
Configure the amount of time that a remote IPv6 node is considered available after a reachability confirmation event has 
occurred.
E-Series
Syntax
ipv6 nd reachable-time {milliseconds}
To restore the default time, use the no ipv6 nd reachable-time command.
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