I have not read all the comments but I thought I would try this
I configured OSPF on a single router and ran "debug ip ospf adja" *Mar 1 00:01:07.091: OSPF: Interface FastEthernet0/0 going Up *Mar 1 00:01:07.595: OSPF: Build router LSA for area 0, router ID 1.1.1.1, seq 0x80000001 *Mar 1 00:01:47.091: OSPF: end of Wait on interface FastEthernet0/0 *Mar 1 00:01:47.091: OSPF: DR/BDR election on FastEthernet0/0 *Mar 1 00:01:47.095: OSPF: Elect BDR 1.1.1.1 *Mar 1 00:01:47.095: OSPF: Elect DR 1.1.1.1 *Mar 1 00:01:47.099: OSPF: Elect BDR 0.0.0.0 *Mar 1 00:01:47.099: OSPF: Elect DR 1.1.1.1 *Mar 1 00:01:47.103: DR: 1.1.1.1 (Id) BDR: none *Mar 1 00:01:47.603: OSPF: No full nbrs to build Net Lsa for interface FastEthernet0/0 Does this help? From: [email protected] [mailto:[email protected]] On Behalf Of David Betz Sent: November-24-10 3:37 AM To: [email protected] Subject: Re: [OSL | CCIE_RS] OSPF Election Time That's my current theory. However, this really shouldn't be a theory, but scientific fact. I've looked at the RFC and still haven't found anything. Granted, it was a skim. I'd need to scan it to be sure of it's absence or presence. On Wed, Nov 24, 2010 at 2:10 AM, antonio <[email protected]> wrote: Maybe you have to look at wait timer (by default equals to dead-interval) regards antonio Il 24/11/2010 03:43, David Betz ha scritto: Upon closer examination of the process, it seems that DR/BDR election is based on the candidates that are adjacencies (neighbor routers with priority > 0). Thus, the question is pushed backed a step: when does a router say "I've 2-way with n-number of routers on this broadcast segment, let's begin election."? Even then, multiple routers are doing this, but given that that is per-segment, the election results should be the same all over. So, that part shouldn't be an issue. On Tue, Nov 23, 2010 at 7:58 PM, David Betz <[email protected] <mailto:[email protected]>> wrote: Yes? I've done this experiment myriad times and looked over the data for a long time. What is your personal analysis of this data? Any conclusion? I've not been any to come up with with anything based on this data. If we are going to do our work off empirical data, we need to have a series of tests with a specified baseline. However, I'm more looking for an axiom from the [seemingly non-existent] documentation. Normally I'd look at the RFC, but do not any any reason to think that Cisco is following it at this point. On Tue, Nov 23, 2010 at 7:49 PM, Jason Maynard <[email protected] <mailto:[email protected]>> wrote: Have a look at the times below. Between two routers in a broadcast network *Mar 1 00:09:00.215: OSPF: end of Wait on interface FastEthernet0/0 *Mar 1 00:09:00.215: OSPF: DR/BDR election on FastEthernet0/0 *Mar 1 00:09:00.219: OSPF: Elect BDR 222.222.222.222 *Mar 1 00:09:00.219: OSPF: Elect DR 222.222.222.222 *Mar 1 00:09:00.223: OSPF: Elect BDR 0.0.0.0 *Mar 1 00:09:00.223: OSPF: Elect DR 222.222.222.222 *Mar 1 00:09:00.227: DR: 222.222.222.222 (Id) BDR: none *Mar 1 00:09:00.323: OSPF: 2 Way Communication to 1.1.1.1 on FastEthernet0/0, state 2WAY *Mar 1 00:09:00.323: OSPF: Neighbor change Event on interface FastEthernet0/0 *Mar 1 00:09:00.327: OSPF: DR/BDR election on FastEthernet0/0 *Mar 1 00:09:00.327: OSPF: Elect BDR 1.1.1.1 *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222 *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR: 1.1.1.1 (Id) *Mar 1 00:09:00.331: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xA62 opt 0x52 flag 0x7 len 32 *Mar 1 00:09:00.331: OSPF: Neighbor change Event on interface FastEthernet0/0 *Mar 1 00:09:00.331: OSPF: DR/BDR election on FastEthernet0/0 *Mar 1 00:09:00.331: OSPF: Elect BDR 1.1.1.1 *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222 *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR: 1.1.1.1 (Id) *Mar 1 00:09:00.331: OSPF: Neighbor change Event on interface FastEthernet0/0 *Mar 1 00:09:00.331: OSPF: DR/BDR election on FastEthernet0/0 *Mar 1 00:09:00.331: OSPF: Elect BDR 1.1.1.1 *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222 *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR: 1.1.1.1 (Id) *Mar 1 00:09:00.331: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x1376 opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART *Mar 1 00:09:00.331: OSPF: First DBD and we are not SLAVE *Mar 1 00:09:00.379: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xA62 opt 0x52 flag 0x2 len 52 mtu 1500 state EXSTART *Mar 1 00:09:00.383: OSPF: NBR Negotiation Done. We are the MASTER *Mar 1 00:09:00.387: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xA63 opt 0x52 flag 0x3 len 52 *Mar 1 00:09:00.475: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xA63 opt 0x52 flag 0x0 len 32 mtu 1500 state EXCHANGE *Mar 1 00:09:00.479: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xA64 opt 0x52 flag 0x1 len 32 *Mar 1 00:09:00.483: OSPF: Send LS REQ to 1.1.1.1 length 12 LSA count 1 *Mar 1 00:09:00.567: OSPF: Rcv LS REQ from 1.1.1.1 on FastEthernet0/0 length 36 LSA count 1 *Mar 1 00:09:00.571: OSPF: Send UPD to 10.0.0.2 on FastEthernet0/0 length 40 LSA count 1 *Mar 1 00:09:00.619: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xA64 opt 0x52 flag 0x0 len 32 mtu 1500 state EXCHANGE *Mar 1 00:09:00.623: OSPF: Exchange Done with 1.1.1.1 on FastEthernet0/0 *Mar 1 00:09:00.623: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 64 LSA count 1 *Mar 1 00:09:00.627: OSPF: Synchronized with 1.1.1.1 on FastEthernet0/0, state FULL *Mar 1 00:09:00.631: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done *Mar 1 00:09:00.727: OSPF: Build network LSA for FastEthernet0/0, router ID 222.222.222.222 *Mar 1 00:09:00.731: OSPF: Build network LSA for FastEthernet0/0, router ID 222.222.222.222 *Mar 1 00:09:00.735: OSPF: Build router LSA for area 0, router ID 222.222.222.222, seq 0x80000004 *Mar 1 00:09:03.439: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 64 LSA count 1 *From:*Jason Maynard [mailto:[email protected] <mailto:[email protected]>] *Sent:* November-23-10 8:25 PM *To:* 'David Betz'; '[email protected] <mailto:[email protected]>' *Subject:* RE: [OSL | CCIE_RS] OSPF Election Time Well that depends How long does the device take to boot up compared to other devices When is the device ready to participate in the OSPF election process (running more services on a device may take it longer to start participating compared to a router with less services) DR and BDR election is done via the Hello protocol - OSPF Network Type | Hello | DR/BDR | _________________________________________ Broadcast | 10sec | Elects DR/BDR| _________________________________________ NonBroadcast | 30sec | Elects DR/BDR| _________________________________________ P2MP | 30sec | No DR/BDR | _________________________________________ P2MP NonBroadcast | 30sec | No DR/BDR | _________________________________________ P2P | 10sec | No DR/BDR | If you want to control which devices become the DR/BDR you can use "*ip ospf priority" and set all devices that you do not want to be DR/BDR to "0" *** Not sure exactly how may hellos before the DR/BDR election takes place, perhaps I will lab it up to see - HTH *From:*[email protected] <mailto:[email protected]> [mailto:[email protected] <mailto:[email protected]>] *On Behalf Of *David Betz *Sent:* November-23-10 7:32 PM *To:* [email protected] <mailto:[email protected]> *Subject:* [OSL | CCIE_RS] OSPF Election Time I've not been able to figure this out nor can I find any documentation for this: how long does OSPF wait for others to cast their vote before doing the DR/BDR election? If R1, R2, and R3 come online with 10.1.1.X/25 (X=RX) ip addresses, and R1 and R2 see each other's messages, they will start an election. If R3 is there, it wins... if it's too late, R2 wins. When is "too late"? _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
