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Can the lifetime of default route (in RA) to the client be renewed?


The question is that why the "lifetime" for the "ipv6 nd ra" is set maximum 1800sec? It equals to just 30mins.

If this timer is expired, how to renew the RA to the client? If the renewal is not possible, the client will loss the default

route information forever. What is the solution for client not loss the default route (except the manual configuration)?

Thank you

7 Replies 7

Laurent Aubert
Cisco Employee
Cisco Employee


It's not really a lifetime at such. A non zero value means this router can be considered as a default-gateway.

From RFC 4861:


 Router Lifetime
                     16-bit unsigned integer.  The lifetime associated
                     with the default router in units of seconds.  The
                     field can contain values up to 65535 and receivers
                     should handle any value, while the sending rules in
                     Section 6 limit the lifetime to 9000 seconds.  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.


Also please refer to




The lifetime in this case is just notify the client that this route can be considered as a default route. The reason to ask the question is because it is related to the following issue.

To setup a ISATAP tunnel, ISATAP server should send RA (a prefix) with a non-zero lifetime to the client, so that the client will treat this route as default route. Once the tunnel is built up, the default route pointing to server is available. But after the lifetime, the route disappears and never come back. How to figure this out?