Re: LSDB Overflow Limitation?

[Erblichs <[e-mail]>]

Charles,

        The number really has to do with
        the number of non default AS-external
        LSAs.

        These are believed to represent the
        maj of LSAs in the LSDB.

        In my experience, this only occurs
        with memory limited routers and
        routers within the same area are
        normally set to the same values.

        Realize that in memory limited routers,
        you are pre-allocating enough memory
        to cover the limit and that memory will
        not be available for other functions.

        Mitchell Erblich
        -----------------

> Charles Yi-tung Liang wrote:
>
> Hi,
>
> Here below is my understanding from RFC1765
> to process lsdb overflow condition.
>
> Goal: Make every OSPF router to be awared of
> the overflow state, and thus reduce the number
> of lsdb.  That's why we required all the OSPF
> routers setup the same limited lsdb threshold.
>
> Process: As mentioned in RFC1765.
>
> Limitation?/Problem?:
> Since the new LSA update from someone triggers
> overflow state (when currentLSACount == limitedLSACount)
> via flooding, there is chance that certain OSPF router
> will miss such a critial event.  Moreover, the following
> premature actions may make someone else believing
> there is not yet an overflow event.  Why don't we just set
> up a beacon bit to notify everyone?  For example,
> using a reserved filed in HELLO-Option to notify
> overflow.  Afterward, when all the neighbors acked
> with overflow beacon-bit, reset (clear) such a bit.
>
> Could anyone help clearing my doubt?
>
> BTW, if the overflow process needs to be applied
> to Inter-AS LSAs (Area-Oriented), what kind of
> LSA is suggested to be prematured?  Can I leave
> RTRLink, NetLink, and ASSummary alone?
> Will OSPF WG include the overflow process as
> a part of OSPFv3?
>
> Thanks in advance.
>
> Charles