Well that depends 

 

How long does the device take to boot up compared to other devices  

When is the device ready to participate in the OSPF election process
(running more services on a device may take it longer to start participating
compared to a router with less services)

 

DR and BDR  election is done via the Hello protocol -

 

OSPF Network Type           | Hello | DR/BDR |
_________________________________________
Broadcast                              | 10sec | Elects DR/BDR|
_________________________________________
NonBroadcast                      | 30sec | Elects DR/BDR|
_________________________________________
P2MP                                     | 30sec | No DR/BDR | 
_________________________________________
P2MP NonBroadcast          | 30sec | No DR/BDR |
_________________________________________
P2P                                         | 10sec | No DR/BDR |

 

If you want to control which devices become the DR/BDR you can use "ip ospf
priority" and set all devices that you do not want to be DR/BDR to "0" 

 

Not sure exactly how may hellos before the DR/BDR election takes place,
perhaps I will lab it up to see -

 

HTH

 

 

 

 

From: [email protected]
[mailto:[email protected]] On Behalf Of David Betz
Sent: November-23-10 7:32 PM
To: [email protected]
Subject: [OSL | CCIE_RS] OSPF Election Time

 

I've not been able to figure this out nor can I find any documentation for
this: how long does OSPF wait for others to cast their vote before doing the
DR/BDR election?

 

If R1, R2, and R3 come online with 10.1.1.X/25 (X=RX) ip addresses, and R1
and R2 see each other's messages, they will start an election.  If R3 is
there, it wins... if it's too late, R2 wins.

 

When is "too late"?

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