@AK: Not quite. We don’t have any frame-relay anymore (haven’t for years). We have probably 70 sites altogether. The larger sites have a fiber connection back to one of two central sites (we run OSPF over these links). These sites also have (typically, multiple) T-1’s into AT&T’s MPLS cloud and that traffic exits the MPLS cloud at the other central site (whichever one their fiber doesn’t run to).

The switch could be replaced with a frame-relay cloud, however the OSPF configuration would be different (think about your different types of OSPF network types).

@Edwin Jean: The OSPF configurations would depend on the OSPF network types in use, which would depend on the frame-relay configurations, e.g. one large point-to-multipoint, or multiple point-to-points, etc. I’ll try to post more example configurations soon with the different network types.

@Prithivi: You’re very welcome! Visit again soon and I’ll work on getting some more “labs” posted.

-Jeremy

FYI, I tried posting a comment on your site as well, but couldn’t post for some reason.

Thanks, -j

You’re quite correct that there is no way to ensure that a specific router will always be the BDR because it will be “promoted”, as you mentioned, to DR if/when the DR goes away.

Quote from the post:

“To fully meet the requirements, we must ensure that, under normal circumstances, the ISP router will be the DR, the Remote1 router will be the BDR, and that the Remote2 will never even attempt to participate in the election process.”

I’m not sure it’s possible to have a BDR that would never become a DR — I’m quite certain it’s not, as that would defeat the whole purpose of a BDR.

That said, this was a very introductory lab modified just slightly from a Cisco Network Academy lab for OSPF. I made it specifically for a friend of mine who is in that program, but posted it here “for the world”. I think you read a bit more into it than I expected the “intended audience” would.

“I re-did your lab and posted my findings. I hope you don’t mind.”

Not at all. I’m no expert on anything about which I post. If I’m wrong, I hope that others do, indeed, point out my mistakes. It will only benefit all of us who come across these articles!

thats the full url….incase you read this after several updates on my main page.

thanks

the requirement to have the ISP router as the DR and Remote2 as the BDR even under normal circumstances can’t be met simply because if the DR goes off for some reason, the BDR will be upgraded to DR and it will stay that way. My point is I don’t know of any automated way to do this. I re-did your lab and posted my findings. I hope you don’t mind: I hope we’re both wrong and someone corrects us….:-)

http://third-world-networker.blogspot.com Regards, Gitau