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Home > Archive > alt.certification.cisco > January 2003 > Suboptimal routing IS-IS, can this be possible...
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Suboptimal routing IS-IS, can this be possible...
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| Hi folks, quick little question:
Does a L1 router forward packets intended for another area to the nearest
L1L2
even if the L1L2 does not have L2-connectivity to the other destination
area...?
As the L1L2 sends L1-LSP into L1-area with the attached bit set to "default
metric" is the
above the result?
/Fred
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| Jesper Skriver 2003-01-28, 1:24 pm |
| On Tue, 28 Jan 2003 18:11:50 +0100, Foo wrote:
> Hi folks, quick little question:
>
> Does a L1 router forward packets intended for another area to the
> nearest L1L2 even if the L1L2 does not have L2-connectivity to the
> other destination area...?
If you do not leak routes into the L1 area, (and we for a second assume
you doens't use other routing protocols) the L1 routers will use either
a explicit default route in ISIS, or the closes L1L2 router as default
gateway (attach bit).
This is the reason you need to ensure that the L2 part of the network is
contigious at all times.
--
Jesper Skriver, CCIE #5456
FreeBSD committer
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| That is what I thought. And if I only route OSI there is no way to leak
routes either..?
Or?
/Fred
"Jesper Skriver" <harvest@wheel.dk> wrote in message
news:slrnb3djg0.djg.harvest@freesbee.wheel.dk...
> On Tue, 28 Jan 2003 18:11:50 +0100, Foo wrote:
>
> > Hi folks, quick little question:
> >
> > Does a L1 router forward packets intended for another area to the
> > nearest L1L2 even if the L1L2 does not have L2-connectivity to the
> > other destination area...?
>
> If you do not leak routes into the L1 area, (and we for a second assume
> you doens't use other routing protocols) the L1 routers will use either
> a explicit default route in ISIS, or the closes L1L2 router as default
> gateway (attach bit).
>
> This is the reason you need to ensure that the L2 part of the network is
> contigious at all times.
>
> --
> Jesper Skriver, CCIE #5456
> FreeBSD committer
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| Jesper Skriver 2003-01-28, 2:24 pm |
| On Tue, 28 Jan 2003 20:36:03 +0100, Foo wrote:
> That is what I thought. And if I only route OSI there is no way to
> leak routes either..?
None that I know if, that is to my best knowledge a IP only feature.
/Jesper
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