Subject: Re: DR election

From: Igor Miroshnik <[email-masked]>
Date: Tue, 13 May 2003 07:42:28 -0400

On Tue, 13 May 2003 06:57:34 -0400, Dror <[email-masked]> 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

In case of DR/BDR having already been elected, no new DR/BDR election will
ensue, since only R3 lists itself as DR, and only R2 lists itself as BDR.
R4 will analyze the BDR-candidate list of a single member (R2), and one for
DR (listing merely R3). As there is no choice, R4 will agree upon the
existing DR/BDR.
   On the other hand, if none of the routers declares itself DR/BDR yet, R4
will run its own candidature, and take on the job.