Re: DR election

[kamatchi soundaram <[e-mail]>]

R4 will become DR.
GKS
----- Original Message -----
From: "Zebaida, Dror (Dror)" <[e-mail]>
To: <[e-mail]>
Sent: Tuesday, May 13, 2003 6:46 AM
Subject: Re: DR election


> Hi Phil,
>
> I don't mean exactly a partitioned network. This is what I mean:
>
> 1)      R1 -------------------R2
>                          |
>                          |     N10
>                          |
>                 R3
>
> 2) All connected and R3 is elected to be the DR since it has the highest
router ID.
>
> 3) R4 is configured to run ospf on an interface belonging to N10. However
it is not physically connecet to N10
>
> 4) R4 is transitioned out of it WAIT state after 40 seconds thinking it's
alone on N10 (not receiving any HELLOS)
>
> 5) R4 is physically connected to N10
>
> 6) R1/R2/R3 all send HELLOS with R3 DR and R2 BDR.    R4 sends HELLO with
R4 DR
>
> 7) what happens now???        R3 remains DR  or   R4 is selected to be DR.
>
>
> Hope this is clear
> Thanks
> Dror
>
>
>
>
>
>
> -----Original Message-----
> From: Phil Chen [mailto:[e-mail]]
> Sent: Tuesday, May 13, 2003 4:29 PM
> To: [e-mail]
> Subject: Re: DR election
>
>
> If I understand you correctly, you are talking about a situation where a
IP subnetwork is partitioned (may be due to some layer 2 problems) where
each partition may have tis own DR/BDR. In this case, when partitions are
merged, R4 will be the new DR for the final healed IP subnetwork. R3 will
become DR-other. R2 remains as BDR (unless there is another BDR from other
partition).
>
> --Phil
>
>
>
> -----Original Message-----
> From: Zebaida, Dror (Dror) [mailto:[e-mail]]
> Sent: Tuesday, May 13, 2003 8:04 AM
> To: [e-mail]
> Subject: Re: DR election
>
>
> I understand that if there is already a DR/BDR then R4 will not become the
DR.
> However, when an interface transitions out of the WAIT state, if it thinks
it is
> alone on the network, it declares itself the DR.  If after that, it
connects to the
> network, there are 2 routers declaring themselves DR. In our case R3 and
R4.
> At this stage, is a new DR elected, or does R3 remain the DR.
>
> The scenario I am describing is R4 is conneced to the network after it
transitioned
> out of the WAIT state (after 40 seconds)
>
> Thanks
>
>
>
> -----Original Message-----
> From: Russ White [mailto:[e-mail]]
> Sent: Tuesday, May 13, 2003 2:56 PM
> To: [e-mail]
> Subject: Re: DR election
>
>
> As long as there is already a dr on the link, R4 would not take over as
the
> DR. Or it shouldn't. Think of it this way: The DR isn't elected first, the
> BDR is. Then the routers attached to the link "discover" there is no DR,
> and promote the BDR to DR, and elect a new BDR.
>
> :-)
>
> Russ
>
> On Tue, 13 May 2003, Dror wrote:
>
> > Hi,
> >
> > I have a question regarding a DR election algorithm.  If I have a
netowrk
> > with 3 routers R1,-R3, each having the same priority and with router IDs
> > 0.0.0.1, 0.0.0.2, 0.0.0.3 respectively.
> >
> > After a DR election process is done, R3 will be DR, R2 will be BDR and
R1
> > will be DR-Other.  This is the result of the DR election process since
R3
> > has the largest router ID.
> >
> > If I add a new router R4 with router ID 0.0.0.4, do I expect R4 to
become
> > the DR, or does it just become another DR-other since there is already a
DR
> > in the network.
> >
> > Does the result depend on whether R4 is connected to the network when it
is
> > still in the WAIT state, or the result is the same nevertheless.
> >
> > Thanks
> > Dror
> >
>
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