That is the point I needed clarification on. Just seemed odd that the DR would not be established first, followed by the BDR. For a brief moment when the routers are first started, there is no DR, but there is a BDR. I wonder what the logic for that is.
-----Original Message----- From: Zsombor Papp [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 8:20 PM To: [EMAIL PROTECTED] Subject: RE: OSPF DR and BDR elections [7:73504] Technically, the BDR is elected first. If no router is claiming to be a DR, then the BDR will be immediately promoted to DR. Nonetheless, the end result is pretty much what the web page referenced below describes. Thanks, Zsombor mccloud mike wrote: > > The DR is elected first by highest priority, the tie breaker is > highest RID. Then the process is repeated for the BDR. > > http://www.cisco.com/warp/customer/104/2.html#10.1 > > My understanding is that if the DR goes down then the BDR is > promoted to DR and an election is held for the new BDR. This > means that when the original DR comes back up it can not become > DR until both of the current DR and BDR go offline. > > Cheers, Mike > > DeVoe, Charles (PKI) wrote: > > > > If I am understanding this correctly. There are no routers up > > in the > > network. I turn on 3 routers simultaneously at the same > time. > > The routers > > will first select the BDR. They will then look for the DR. > > Since none > > exist, the BDR will be promoted to DR. Then another election > > will be held > > to find a new BDR. Is this correct? > > > > -----Original Message----- > > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, August 05, 2003 11:01 AM > > To: [EMAIL PROTECTED] > > Subject: RE: OSPF DR and BDR elections [7:73504] > > > > > > The DR is not chosen from the "remaining list." The DR is > > chosen from the > > list of routers that declared themselves designated routers > > (this is why a > > high-priority router that comes up late won't take over the DR > > role from an > > existing DR), or if no router declared itself DR, then the BDR > > will become > > DR (this is why a high-priority router that came up late won't > > necessarily > > become DR even if the existing DR dies). > > > > See RFC2328, Page 75 for more details. > > > > Thanks, > > > > Zsombor > > > > DeVoe, Charles (PKI) wrote: > > > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > > > from Sybex. In > > > the OSPF section under the discussion of DR and BDR (page > > 171) > > > he says that > > > the BDR is chosen first and that the DR is chosen from the > > > reaming list. > > > That seems illogical and backwards. Can someone please > > confirm > > > or deny and > > > explain it. Thanks > > **Please support GroupStudy by purchasing from the GroupStudy > > Store: > > http://shop.groupstudy.com > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73597&t=73504 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
