1 00:00:08,030 --> 00:00:14,690 In this video we're going to discuss Oh SPF designated rowdies or bras and backup designated Rodders 2 00:00:14,700 --> 00:00:15,800 or BDO. 3 00:00:16,560 --> 00:00:22,020 This is one of multiple videos and in this first video let's see if we can answer some basic questions 4 00:00:22,890 --> 00:00:24,450 in this topology. 5 00:00:24,450 --> 00:00:27,150 How many designated riders are there. 6 00:00:27,150 --> 00:00:40,880 In other words how many dealers will be elected in this topology. 7 00:00:41,520 --> 00:00:47,970 Second question how many backup designated routers or BDO cars are they in this topology 8 00:00:53,770 --> 00:01:03,490 and thirdly how many D or others or druthers are they in this topology. 9 00:01:03,910 --> 00:01:11,650 So can you answer how many dealers how many BD hours how many days are others are there in this topology 10 00:01:13,600 --> 00:01:20,350 notice that brought one rider to write a three and Rod a four or connected to a layer to switch. 11 00:01:20,350 --> 00:01:27,260 There is no configuration on the switch route a force connected to ratify via serial link and route 12 00:01:27,260 --> 00:01:31,660 of five is connected to wrote a six via an Ethernet link. 13 00:01:31,690 --> 00:01:36,700 How many dealers how many BDO hours how many days or others. 14 00:01:36,700 --> 00:01:42,650 So let's configure the topology and find out in this topology of only configured IP addresses. 15 00:01:42,730 --> 00:01:51,180 I haven't configured always SPF so not a one show IP protocols or SPF is not configured 16 00:01:54,780 --> 00:02:02,250 Let's paste a basic o SPF configuration onto the rudder we've enabled or SPF on all interfaces on the 17 00:02:02,250 --> 00:02:05,930 router show IP or SPF interface. 18 00:02:06,000 --> 00:02:18,290 Brief SPF is enabled on gigabit 00 current state is weight that's the link here gigabit 00 is the link 19 00:02:18,710 --> 00:02:19,490 to the switch 20 00:02:22,490 --> 00:02:29,030 after a while the state should change but the rudder waits to see if other route are configured on the 21 00:02:29,030 --> 00:02:37,420 same segment in this example the Rada has become the designated Rada that would make sense because there 22 00:02:37,420 --> 00:02:48,560 are no other routers configured on the layer to switch and brought it to show IP protocols SPF is not 23 00:02:48,560 --> 00:02:58,100 currently running paste the OSP SPF config in neighbor relationship has been established and the state 24 00:02:58,100 --> 00:03:07,100 has gone to full show IPO SPF neighbor we can see that Rider 2 has formed a relationship with Rod a 25 00:03:07,090 --> 00:03:18,490 1 rather 1 is the D.R. a full relationship exists to that broader show IPO SPF interface brief shows 26 00:03:18,490 --> 00:03:28,650 us that the local Rada is a backup a designated Rada What about Rada 3 show IP protocols or SPF is not 27 00:03:28,650 --> 00:03:38,160 currently enabled on the strata salt paste in the configuration the Rada has formed to neighbor relationships 28 00:03:38,730 --> 00:03:50,280 one with a one one with Robert to sort of show IP 0 SPF interface brief who SPF is enabled on the local 29 00:03:50,280 --> 00:03:54,920 gigabit 00 interface the router is a D or other. 30 00:03:55,250 --> 00:04:02,690 In other words SPF is running on this interface gigabit 00 router 3 has become a D or other or draw 31 00:04:02,690 --> 00:04:11,980 the show IP who is P.F. Neighbor to Neighbor relationships exist one to right of one who's the D.R. 32 00:04:12,730 --> 00:04:20,980 another 2 rod a 2 which is the BTR notice full relationship which means that rod so exchanged between 33 00:04:21,250 --> 00:04:30,050 these routers so Rada 3 will synchronize its 0 SPF database with a 1 and Rod a 2. 34 00:04:30,150 --> 00:04:38,310 Okay so Rod 4 show IP protocols who Piff is not enabled on this Rhonda 35 00:04:41,350 --> 00:04:47,410 the output is different here because this road is running version twelve four of IAW with these other 36 00:04:47,410 --> 00:04:51,490 riders are running fifteen point six. 37 00:04:51,490 --> 00:05:01,920 They are Iowa's v riders whereas this rider is a C 30 725 rider so IP protocol shows no writing protocols 38 00:05:02,940 --> 00:05:12,900 all enable or SPF on all interfaces on this rider show IP 0 SPF interface brief this Rada is acting 39 00:05:12,900 --> 00:05:20,400 as a D or other on the fast ethernet interface and it has a point to point connection on the serial 40 00:05:20,400 --> 00:05:29,850 interface we can see that a relationship was formed to route a two and wrote a one so show IP SPF neighbor 41 00:05:30,880 --> 00:05:35,670 it only forms a full relationship with Russia one and wrote it two. 42 00:05:35,680 --> 00:05:44,080 In other words the D.R. and the PDR it does not form a full relationship was wrote a three on route 43 00:05:44,080 --> 00:05:49,050 a three we should see something similar previously rudder three had a full relationship with rudder 44 00:05:49,050 --> 00:05:56,940 one and rudder too it still has that but it has a two way relationship or half formed relationship with 45 00:05:57,050 --> 00:06:06,590 Russia for so on this Ethernet segment we have one the D.R. will ADR and BDO are be elected on this 46 00:06:06,590 --> 00:06:19,890 link so let's test that three out of five show IP protocols no protocols are running let's enable SPF 47 00:06:21,520 --> 00:06:28,840 show IP 0 SPF interface brief 0 SPF is enabled on the serial interface as well as the first Ethernet 48 00:06:28,840 --> 00:06:31,140 interface of router 5. 49 00:06:31,150 --> 00:06:39,620 So it's running here and here currently it's set to wait on first Ethernet it's point to point on the 50 00:06:39,620 --> 00:06:51,810 serial notice stall point to point on the serial show IP who SPF neighbor this Rada has a full relationship 51 00:06:52,260 --> 00:07:02,100 to root a for but we don't have an election OSP FDR and PDI elections do not take place on cereal point 52 00:07:02,100 --> 00:07:12,790 to point links so in a fool once again it's formed a full relationship to write a five but no election 53 00:07:12,790 --> 00:07:19,420 took place on the serial link on the serial interface there was no election and election did take place 54 00:07:19,480 --> 00:07:30,840 on the ether net link and therefore we have a D.R. BTR and in this example another D or other so on 55 00:07:30,840 --> 00:07:38,250 this part of the network the switch we have a designated Rada elected no designated Rada was elected 56 00:07:38,280 --> 00:07:46,450 on the serial link what about on this Ethan a link between Rada five and wrote a six back on Rada five 57 00:07:47,470 --> 00:07:55,450 notice Rada five became the designated Rada on this segment because there are no other rorters running 58 00:07:55,460 --> 00:08:10,340 Oh SPF on that segment so if we enable o SPF on RORT a 6 1 happens show IP 0 SPF interface brief router 59 00:08:10,350 --> 00:08:20,620 6 has become a PDR it's formed a relationship with Rod a 5 show IPO SPF neighbor we can see that right. 60 00:08:20,630 --> 00:08:27,380 Five is the designated rudder full relationship between rudder six and rudder five right. 61 00:08:27,380 --> 00:08:36,390 Six is the BTR so in answer to the questions How many dealers are elected in this topology. 62 00:08:36,520 --> 00:08:42,410 Answer is to how many BDO hours are elected in this topology. 63 00:08:42,410 --> 00:08:51,380 The answer is to write a one and Root a five or designated Rodders write a two and write a six are backup 64 00:08:51,530 --> 00:09:01,680 designated route or BDO RS write a three and write a four on the segment are D or others. 65 00:09:01,860 --> 00:09:10,230 So what you need to know is that a designated writer is elected on a per segment basis but only on broadcast 66 00:09:10,290 --> 00:09:14,140 multi access or non broadcast multi axis links. 67 00:09:14,250 --> 00:09:19,950 In other words links or interfaces where you can have more than one product connected to that single 68 00:09:19,950 --> 00:09:30,140 segment or single subnet so as an example if we added another link between right of 1 and root of 4 69 00:09:31,070 --> 00:09:38,610 we would end up seeing that one of these writers is the designated Rada on the segment and to show you 70 00:09:38,610 --> 00:09:50,090 that erotic can be ADR as well as a BTR or D or other what all D is no shut the link on Rada for first 71 00:09:51,580 --> 00:09:57,390 and configure rather for first so that it becomes the D.R. on that link. 72 00:09:57,430 --> 00:10:07,850 So show IP or SPF interface brief on Fost Ethan at 0 1 we are in the White state so it's waiting for 73 00:10:07,850 --> 00:10:15,420 another router might take it a while so while we're doing that too let's configure an IP address on 74 00:10:15,900 --> 00:10:26,640 router 1 but I won't no shut the interface so that interface is shut I'll configure an IP address on 75 00:10:26,640 --> 00:10:36,950 the interface but I want to know shut it yet notice a 4 has become the designated Rada on this segment 76 00:10:38,660 --> 00:10:47,690 so now and write a one oh no shut the interface show IP who is P.F. interface brief relationship is 77 00:10:47,690 --> 00:10:58,540 formed and when I present to know we can see that brought a 1 is a backup designated rata on gigabyte 78 00:10:58,660 --> 00:11:07,590 0 1 so we've changed the topology slightly now we have a designated Rata which is rather one over here 79 00:11:08,350 --> 00:11:16,140 at designated Rata here which is not a 4 and it designate errata here which is rather a 5 about a 6 80 00:11:16,140 --> 00:11:23,820 is a backup designated rata on the segment on this layer to segment write it to is a backup designated 81 00:11:23,820 --> 00:11:33,900 rota and on this segment write a 1 is a backup designate Rata so notice on write a 1 it's a designated 82 00:11:33,900 --> 00:11:41,920 rata on one segment and a backup designated rata on another segment designated Rod as backup designated 83 00:11:41,930 --> 00:11:52,680 routers are chosen on a per segment basis but only on multi axis networks or segments I hope you found 84 00:11:52,740 --> 00:11:59,670 the video useful if you enjoyed it please like it and please subscribe to my YouTube channel I wish 85 00:11:59,670 --> 00:12:00,920 you all the very best.