02-14-2018 11:35 AM - edited 03-01-2019 05:55 PM
Can anyone point me to or tell me how the 'lifetime' works in a prefix announced via Router Advertisement? Is the default lifetime 30 days (that's what I seem to keep seeing)? Also, who (which device) tracks this (router or 'host')? What happens when this 'lifetime' expires (e.g. if tracked by the host, does it send out another RS for a prefix)? etc...
Thanks in advance!
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Mike Manthe
Solved! Go to Solution.
02-19-2018 01:43 AM
Hi there,
The prefix information option sent in an RA is issued by the a router but its state is tracked by the host which receives and configures its preferred address using the defined prefix.
When the lifetime expires the address is marked as depreciated and should not be used as the source for future communication, but it should still be used to receive communications on.
Whenever a host receives a RA packet it will update the lifetime timers. However if a prefix expires and the host becomes unreachable it will perform NUD and in the process send out a NS which would initiate a solicated-RA from the router, updating the prefixes lifetime.
You can find plenty of information here:
https://tools.ietf.org/html/rfc4861
https://tools.ietf.org/html/rfc4862
cheers,
Seb.
02-19-2018 01:43 AM
Hi there,
The prefix information option sent in an RA is issued by the a router but its state is tracked by the host which receives and configures its preferred address using the defined prefix.
When the lifetime expires the address is marked as depreciated and should not be used as the source for future communication, but it should still be used to receive communications on.
Whenever a host receives a RA packet it will update the lifetime timers. However if a prefix expires and the host becomes unreachable it will perform NUD and in the process send out a NS which would initiate a solicated-RA from the router, updating the prefixes lifetime.
You can find plenty of information here:
https://tools.ietf.org/html/rfc4861
https://tools.ietf.org/html/rfc4862
cheers,
Seb.
02-19-2018 09:04 AM
03-03-2018 01:14 AM
Hi Sab,
can we configure prefered lifetime and valid lifetime for prefix, If yes how to configure?
I am using Catalyst 4500 L3switch.
Thanks in advance
03-04-2018 11:50 PM
Hi there,
! interface ethernet 0/0 ipv6 nd prefix-advertisement 2001:0DB8::/35 1000 900 onlink autoconfig !
cheers,
Seb.
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