Subject: [OSPF] DR Election - NeighborChange event

From: "Ramana Koppula-G20085" <[email-masked]>
Date: Thu, 20 Apr 2006 17:53:20 +0800

Hi,
 
Below are two triggers for neighborChange event which result in
invocation of DR election. My doubts are given inline.
 
1) There is no longer bidirectional communication with a neighbor. In
other words, the state of the neighbor has transitioned to Init or
lower.[Taken from NeighborChange event description, Section 9.2 of RFC
2328]

Doubt> Even if the bidirectional communication failed with a DROther
router, is it required to trigger DR Election?

2) The advertised Router Priority for a bidirectional neighbor has
changed. This is again detected through examination of that neighbor's
Hello Packets.[Taken from NeighborChange event description, Section 9.2
of RFC 2328]

Doubt> a) Is the DR Election required if the router priority of DR or
BDR changed to another non-zero, which does not     result in any change
of the DR/BDR.

thanx

ramana

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From: Acee Lindem <[email-masked]>
Date: Mon, 24 Apr 2006 10:30:21 -0400

Ramana,
Similar to the SPF calculation, if you can come up with little internal 
optimizations that yield
the same result, you are free to implement them. In the cases below, given
everything else constant, it seems that a DR election would not yield a 
change in DR/BDR.
However, having a DR/BDR election triggered for all routers on the
multi-access is arguably more robust. Also, at least one extension has 
been suggested
that takes advantage of this property.

Thanks,
Acee

Ramana Koppula-G20085 wrote:

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