Re: Graceful Restart

[Padma Pillay-Esnault <[e-mail]>]

One important point is that the DR is the one who issues
the network LSA and have adjacency with. If you change
the DR then this would imply that

- All the routers will have to tear down their previous
adj to the restarting router and build a new one to the DR.
Flooding patterns will change which is not desirable.

- the new DR will build the new network LSA for the
network and this will cause the restart to abort on
change in topology.

Padma

>
> Krishna,
> my 2 euros (dollars are out !!!)
>
> >
> > draft-ietf-ospf-hitless-restart-07.txt:
> > 2.  Operation of restarting router:
> >
> > Point 2) If the restarting router determines that it was
> > Designated
> >           Router on a given segment immediately prior to the
> > restart,
> >           it elects itself as Designated Router again
> >
> > Q1)Why does this need to be done while restarting?
> >     AND
> >     How does it help ??
>
> Its helps in maintaining sanity in the network. Others think that this router is still up
> and continue trusting him as DR. When he comes up he should not break this trust and
> should ideally start operating as a DR.
>
> The basic concept is that if he resigns from DRship then the BDR will take over and they
> will need to again re-elect the BDR .. which is a messy affair. The whole point of
> graceful restart is to avoid such events !!
>
> >
> > Q2)What if normal DR/BDR election takes place "on exiting
> >     graceful restart"
>
> Why do you want to land in this mess? You will again need to re-issue your LSAs, etc.
> Everybody will have to re-synch .. and the whole purpose of graceful restart will be
> defeated.
>
> Others more informed about this protocol can correct me whatever i missed out!
>
> JS
>
>
>
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