Re: Clarification on Flooding

[Acee Lindem <[e-mail]>]

Paresh Khatri wrote:
> HI all,

Hi Paresh,

>
> Would someone be able to explain the following clause in RFC2328 to me ?
>
> This is in Section 13. Flooding Procedure:
>
>     Page 145
>     (6) Else, if there is an instance of the LSA on the sending
>         neighbor's Link state request list, an error has occurred in the
>         Database Exchange process.  In this case, restart the Database
>         Exchange process by generating the neighbor event BadLSReq for
>         the sending neighbor and stop processing the Link State Update
>         packet.
>
> Why is this an error ?  If the LSA is on the Link state request list for the neighbor, are we not expecting that
> LSA from that neighbor ?

Yes - but in this case the instance is the same as the one that is
already in your database. Note that in step (5) (b) it says to
immediately flood a new LSA out some subset of the router's interface.

When this happens the corresponding LSA instance should be removed
from all neighbor's link state request lists (see step (1) (b) on
page 149).

Note that an implemenation may have to make accomodations if LSA
flooding is not immediate. In any case, the specification is correct.


> All responses appreciated.
> Paresh Khatri.
>


--
Acee