From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Mon Oct 21 2002 - 11:40:22 GMT-3
At 10:10 PM -0400 10/19/02, Peter van Oene wrote:
>OSPF used non preemptive DR selection, and therefore the first
>router up and functional on a segment will likely become the DR and
>stay that way. In hub and spoke, the best thing to do is set your
>spokes to priority 0, therefore making them ineligible to become DR
>and thus your hub should fill that role every time.
Peter brings up an excellent point that has some strong learning
implications, especially for the more theory-oriented written.
Comparing and contrasting different ways to do similar functions, for
me at least, is a great way to learn.
So, I'm going to invite the list to start adding to this comparison
list, and indeed to suggest other lists. This, to me, is the "right
kind of d*mp" -- a review of principles rather than questions.
OSPF ISIS
------------------------------------------
1. "Traffic cop" DR with designated "Traffic cop" pseudonode DIS with no
BDR. Nonpreemptive. explicit backup. Preemptive in the
sense that a new router discovered
during resync will preempt.
2. Random selection of DR, mostly Random selection of DIS, based on
timing-based but affected by highest priority and MAC address
priority and router ID. If a BDR tiebreaker. Previous DIS status is
exists, it always is first to not a factor
become DR.
3. Wide range of controls of Before L1/L2 extension, supported
propagation of non-intra-area only equivalent of OSPF totally
traffic into areas stubby areas outside the backbone.
***** suggestions ****
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