04-11-2007 09:32 AM - edited 03-03-2019 04:30 PM
Hi all,
From the book, Passive interface purpose is to stop individual interfaces from developing adjacencies in an OSPF network
I am not fully understand it, how about we can simply not advertise the directly network
(e.g. RouterA -<192.168.0.0/30>-RouterB ) --we can simply not add 192.168.0.0/30 under ospf 1 of RouterA or
add 192.168.0.0/30 under ospf 1 of RouterB. Then result also can avoid two router become ospf neighbor
04-11-2007 10:17 AM
Downside will be that the Routers connected to Router A (or B), if any, will have no knowledge of subnet 192.168.0.0/30 then.
Thanks.
04-11-2007 10:33 AM
In your specific scenario both methods of
using passive-interface or not advertising
192.168.0.0/30 will have the same result
as inability to establish adjacency and no
LSA sent on that link. However, it can be a
scenario when let's say your router A
has multiple interfaces and use one network
statement to place them all into OSPF process, however one of the interfaces has
to be excluded from OSPF processing...then
passive-interface command comes very handy
as allows you to remove that specific interface without much modifications within
OSPF process.
HTH,
OW
04-11-2007 10:37 AM
Dear Benny,
There is a difference,
To disable sending routing updates on an interface, use the passive-interface command. If you disable the sending of routing updates on an interface, the particular subnet will continue to be advertised to other interfaces since network command is there.
When you give no network command for that subnet, that link state info. won't be advertised to other ospf enabled routers too thro. other ospf enabled interfaces.
Hope it clears,
Rate if it does,
Rgs
04-11-2007 11:17 AM
hi,
In OSPF when you configure any interface as a passive interface then it will stop sending the OSPF packet through that interface so if the neighboring router which is not receving update or any other packet from the locar router about the ospf then it will break the adjancency with it...
and not adding 192.168.0.0/30 with network command it will avoid to send the update of those network...
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