From: Hoyle, Anthony (AL) (ALHoyle@dow.com)
Date: Sat Nov 29 2003 - 08:33:11 GMT-3
Ok Guys,
Here is a good discussion:
Why does OSPF act the way it does forming adjacencies over broadcast mediums /w multiple routers, hee hee hee.. I know for a multi-access medium such as Ethernet, routers running OSPF will form an adjacency with the DR and BDR all other Routers will have two-way adjacencies formed. Sometimes they will be full/drother sometimes they won't. I am aware of a router seeing itself in a neighbors hello packet , thus
Confirming two-way communication and moving to the 2-way state.
For example if you have a full mesh frame-relay cloud /w fifty routers (broadcast network type), there will be several pairs that will stay in two-way (no matter whether you use
Priority or loopback to control the selection of the DR and BDR, or even if you set a few guys to 0-drother) I know Cisco says this is normal behavior, -but two-way state
does not synchronize databases, what is the point -Redundancy? Of course as soon as one of the routers loses a BDR or DR it immediately transitions from the two-way to exstart from
there to full. I guess exchanging LSA's over the cloud /w every other router might be nonsense, but I got it to work one time (about ten routers broadcast medium) -but that might be a fluke*
Any thoughts? This is bothering me..i'm going to read the rfc again..
Anthony Hoyle
EDS
WAN Infrastructure Analyst
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