2.7.3 Packet Tracer - Multiarea OSPF Exploration - Physical Mode (Part 2)

casual recording company based in sao paulo brazil provides self-serve mini recording studios around the city so that anyone can rent a time slot and record their songs by themselves crc began with a singular ospf network located in one building this idea was very popular and consequently the business has grown causing the company to expand into a branch office in a second building at the far end of the city they continue to use single area ospf you will evaluate the impact of the expanded network business is booming the id department in the crc decided to migrate to a multi-area ospf network you will evaluate the impact and benefits derive it from the change to determine if it was a good decision or not crc expansion continues crc has continued to grow and will open a new branch in montpedale uruguay you will configure the area border router for the new area and physically connect the branch office network to the corporate headquarters network through the internet evaluate multi-area ospf network operation crc has migrated their singularia ospf to multi-area ospf explore ospf area one devices in the corporate hq and branch office okay look at this corporate hq on the left is ospf 801 branch office on the right with area 51. and in middle area zero the connection between corporate hq and branch office click the cd icon for sao paulo click here sao paulo okay this is corporate hq on the left branch office on the right there is a orange cable this is the fiber connection between corporate and branch office click corporate hq click here click the rack icon okay hq iron closet click here click a1 abr 1. okay two switches four routers and this is another router a1 avr1 in the logical topology a1 abr-1 this is our area border router okay because it is placed between area zero and area one area border router a1 avr1 this click here and command line interface tab terminal should show that gigabit zero zero and uv one zero are up and two adjacencies have been established if not wait for the ospf loading process to complete okay click on a a1 abr one now you can see two adjacencies to ospf at your senses and gigabit one zero is up gigabit zero zero up and two ospf adjacencies one ospf adjacency for a 51 abr one and another adjacency with a1 r4 okay two neighbors two ospf audio senses joy brood and the enable show a build notice that the routing table on the router a1 avr1 is shorter than it was on router b1 r5 in the single area ospf example in part one okay this is uh this is the routing table a1 avr1 two directly connected networks this ospf inter area ia is ospf inter area the tank 0 0 0 graphics 8 okay is this all the all the networks on branch office this is the the class the network class or summary route for all the networks on branch office okay area 51 so all the networks in branch office was simplified with only one root and when i do 168 0 0 is this network on the switch 1 0 down here to zero okay on the left and three zero up here how are the networks from area 51 displayed in the routing table of a1 avr 1 is just like this all of area 51 networks are displayed as one summarized network and is this line ospf inter area execute the show ipo spf command on router a1 avr1 show a b ospf space which areas are displayed on router a a1 avr 1 area 1 and area 0. area 1 and area 0. okay because a1 avr1 is placed in the middle so that's y is a area border router it is an area border router area 1 and area 0. the backbone area record the number of times that spf algorithm has been executed in each area seven times from 1 and 5 times on area 0. keep the console window for a1 ibr1 open and select router a1 r2 okay this this router this internal router on area one incorporate hq a1 r2 execute show ib root and show ipo spf commands go to a1 r2 click here command line interface tab enter enable and use show ip root show ip root and then compare the output with the output of a1 avr1 okay compare both the routing tables are similar okay the routing tables are similar they have the same roots 172 17 172 17 182 168 0 0 182 6 68 08 when 182 160 000 192.168808 one zero two zero three zero one zero two zero three 0 the the main difference is that a1 r2 has two uh two inter area routes the ospf inter area tank zero zero zero and ospf in the area 172 17 1 0 okay because a a1 r2 displace it on area one so should should have two inter areas area zero and area 51. okay tank zero zero zero and one seventy two seventeen one show ipo spf okay go to a1 r2 show ap or spf space space and [Music] a1 r2 will show only one area only one area because a1 r2 is placed on area one we show only one area area one and spf algorithm executed seven times okay very similar like a1 abr one compare the output with the output with on a1 abr1 similar network should be displayed and the number of spf algorithm execution should be similar record the number of spf algorithm executions okay 7 in this case a1 r2 explore the impact of changes in area 51 okay on this area branch office area 51 keep the console windows open for both routers a1 abr 1 and a1 r2 on the blue toolbar at the top click back level button twice to return to the sao paulo cd okay back sao paulo branch office rug okay on the right branch office click on the rug a51r4 okay and one switch and [Music] five routers and go to a 51r4 here a51r4 click command interface interface tab okay this router a51r4 a51r4 enter enabled the terminal should show that all four gigabit ethernet interfaces are up and that four adjacencies had been established okay a51r4 has four nighthorse one two three and four okay abr one r3 r2 and r1 four night volts okay click on the router you will see one two three four ospf adjacencies for night horse and gigabit one zero up duality to zero rgb three zero up and show ap interface brief gigabit one zero up two zero up three zero four zero four interfaces up for adjacencies show ip spf natural okay four night wars very nice and showy roots so a good space compare the output compare the output of a51 r4 to the output of a1 abr1 and a1 r2 notice that other than a few connected or local routes the same networks are displayed okay compare this routing table with the another routers for example compare with a1 abr1 okay the main difference is the a1 avr1 will show the the networks on the networks on branch office as one only one route okay abr one will show the networks on branch office the networks of area 51 with will be only one line only one route and [Music] a a51 r4 a51r4 you will show these networks like directly connected networks and ospf networks okay you will show this like four directly not connected networks and four ospf networks and you will see the ospf in the area 172.171.0 this is the network of area 0 the connection between [Music] the connection between hq and branch office the connection between a1 avr1 and a51 avr1 the area zero and you will see the networks on the corporate hq and area one you will see the networks one two three four five okay one two three four and a five okay you will see in you will see those networks as interarea ospf networks okay obviously because they are on area one on a different area than 51. record the number of inter-area routes displayed okay on a151r4 in the layer roots one two three four five and six six inter area roots okay one for area zero and five for eighty one 6 in the area roots remember that show ip spf command show ap ospf ospf record the number of spf calculations seven times remember that seven times keep the console window for a51r4 open click a51r2 okay go to a 51r2 so in the physical tab through the power of to simulate a power failure okay so shut down the router so power off the router a51r2 this router okay a51r2 press this button okay now it's power off return to the console for a51r4 you should see console messages that the adjacency with a51r2 is down okay go to a51r4 click here now you will see knife work down and i hold down shall we be root and show ip ospf a51r4 enter showab root and the space this is a rounding table after the simulated failure and up here this was the routing table before the simulated failure and you have only three directly connected networks and previously you had four directly connected networks okay because this this connection the network 10 10 0 20 prefix field is down a51 r4 will have only three neighbors three directly connected networks 0 20 was eliminated okay go again to a5104 after the simulated failure you have two four five six in the area ospf networks and before 2 4 6 also 6 in the area ospf networks and after the after the simulated failure you have ospf networks and before the failure and before the simulated failure you had multiple ospf networks multiple ospf routes and now you don't have ospf routes only or spf in the radio roots okay obviously because a51r2 was powered off and a51r4 now has only directly connected networks joyp ospf show ip or spf spf algorithm executed 11 times before the simulated failure you had only seven times so have the spf algorithm executions increased yes from seven to eleven record the number of spf algorithm executions 11. what networks are missing from the a51r4 routing table okay all directly connected networks on a51r2 10 10 0 12 30 10 10 00 20 30 10 10 00 16 30 10 24 00 24 and look back look back or loopbacks here 1020 networks navigate to a1 r2 and issue should i be root and show ipo spf commands again a1 r2 okay to this router a1 r2 the router in area 1 on corporate hq is the summary route for area 51 still in the routing table okay go to a1 r2 [Music] so show ap roots i want to show it roots is the summary root for area 51 is still in the routing table is this and yes is still in the routing table has the value for spf algorithm executions increase it from the previous step okay go to a1r2 show ib or spf space spf algorithm executed times 11 and before okay before was seven seven times show ip ospf okay 11 times 11 times after the simulation failure and seven times before the simulation failure okay in this packet raiser the answer is yes because the value is increasing from 7 to 11 but in real lab the answer should be no the answer should be no okay this value is increasing because i have waited a long time since i power off the router to check the routing table okay and the answer should be no the and the answer should be no the spf algorithm executions will not increase because the changes in another area like area 51 will not affect the executions of ospf algorithm in area 1. okay will a pink or a tracer between a1 bc one okay a1 pc1 from area one and a51 pc1 and a51pc1 be successful okay the answer is no the pink should fail because a51r2 is power off and and if you will execute tracer between a1 pc1 and a51 pc1 the the tracer should stop on on a51 abr1 okay and try that a one pc one on area one back level go to corporate hq click on wiring cluster go to the pc a1 pc1 click on the pc verify ipconfiguration very good command prompt fields uh being through this pc this ip 10 24 10 10 24 10 destination host unreachable timeout unreachable tracer okay and this hope when i do 16811 is the a1 r1 when i do 168 4 0 is a1 r4 180 168 010 is the interface on a1 abr 1 and 172 17 1 2 is that this interface on a51 abr1 so tracer stops uh once i do seventeen one two that is a51 abr1 okay ctrl c to stop the af51 border router a51abr1 has summarized the 1000a networks and is advertising the summary route to all the other areas topology changes in area 51 such as power failures interfaces connected or ospf network changes will cause spf recalculations on our routers within area 51 but will not cause spf recalculations in area 1. summarize the area 1 roots to be sent to area 51. select router a51r4 and execute the show ib root okay a51r4 okay this is router on area 51 a51r4 so i built compare the output a51 r4 with the output of a1 r4 a1 okay go to a1 r4 and this is a1r4 click here command interface enter enable show ib root okay compare a1 r4 and a51r4 okay and a1r4 the this router on area 1 will show the networks on area 51 has only one line there's only one route because it summarizes all networks all these networks on branch office are summarized in only one route in only one line and the difference is that and on this router okay the main difference is that on this router on this router placed on area 51 the a51r4 router is showing multiple ospf in the area roots for the networks on area one all the networks on area one one two three four and five okay one two three four and five five five lines five routes you should notice that all of the 1816800 networks from area one are showing inside the routing table if someone accidentally removed the cable on a1 r1 18168 how will the routers in area 51 be affected okay if someone removes this cable on a1 r1 all area 51 routers would have spf algorithm executions and would have to update the routing tables okay because a51r4 is showing that network 182.168.1024 and this network will disappear this routing table should be updated and you need spf algorithms executions what could be done to avoid the area 51 recalculations okay router a1 abr one should summarize the 182.6800 prefix16 networks on area one navigate to a1 abr one using the command line interface tab under the following commands to implement ospf summarization for the 181680 network in area one do this okay go to a1 abr one a1 ibr1 enter configure terminal verify we do show running config visual running config enter space space space the process is router ospf process 1 8. rather os ospf one and on area one okay this is area one for area one summarize the range 180 168 000 okay 285 the subnet max 16 prefix is 35 divided by zero zero enter and end okay uh 1816800 with subnet mask 285-5500 to include all the networks on corporate hq to include all the networks on area 1. return to a51r4 and show ap route a51r4 remember a51r4 is placed on the area 51 on branch office a 51 or four i show it roots and now you will see only one line for all the networks on corporate hq okay only one line only one root who is the road in table output different following the summarization the networks from area 1 are all summarized with integrated routes and is this multi-area spf provides the benefit of summarization between areas the summarization helps to reduce the size of routing tables and reduces the frequency of lsi's clinical state advertisements floating throughout the entire system with summarization a change in one area will cause all routers within that area to execute spf rolling tables and spf recalculations for routers in other areas will not be affected connectivity to the downloaded networks still possess an issue you have completed part two to continue to part three close this packet eraser file okay thank you very much you

Channel: Christian Augusto Romero Goyzueta

Views: 467

Keywords: ensa, enterprise networking, security, automation, ccna, version 7, ccna 7, physical mode, packet tracer, ospf, ospfv2, neighbor, single area, multi area, summary, range, multiarea

Id: njifYffA11s

Length: 42min 3sec (2523 seconds)

Published: Mon Nov 01 2021