NXLD43 OSPF open shortest path first part III kho tài liệu bách khoa

OSPF (Open Shortest Path First) Part- III Topology Figure OSPF R1 (config) #int fa0/0 R1 (config-if) #ip add 192.168.101.1 255.255.255.0 R1 (config-if) #no shut R1 (config) #int s0/0 R1 (config-if) #ip add 192.168.1.1 255.255.255.0 R1 (config-if) #no shut R2 (config) #int fa0/0 R2 (config-if) #ip add 192.168.102.1 255.255.255.0 R2 (config-if) #no shut R2 (config) #int s0/0 R2 (config-if) #ip add 192.168.1.2 255.255.255.0 R2 (config-if) #no shut Topology OSPF (Open Shortest Path First) Part- III R2 (config) #int s0/1 R2 (config-if) #ip add 192.168.2.1 255.255.255.0 R2 (config-if) #no shut R3 (config) #int f0/0 R3 (config-if) #ip add 192.168.103.1 255.255.255.0 R3 (config-if) #no shut R3 (config) #int s0/0 R3 (config-if) #ip add 192.168.2.2 255.255.255.0 R3 (config-if) #no shut R3 (config) #int s0/1 R3 (config-if) #ip add 192.168.3.1 255.255.255.0 R3 (config-if) #no shut R3 (config) #int s0/2 R3 (config-if) #ip add 192.168.6.1 255.255.255.0 R3 (config-if) #no shut R3 (config) #int s0/3 R3 (config-if) #ip add 101.1.1.100 255.255.255.0 R3 (config-if) #no shut R4 (config) #int fa0/0 R4 (config-if) #ip add 192.168.104.1 255.255.255.0 R4 (config-if) #no shut R4 (config) #int s0/0 R4 (config-if) #ip add 192.168.3.2 255.255.255.0 R4 (config-if) #no shut R4 (config) #int s0/1 R4 (config-if) #ip add 192.168.4.1 255.255.255.0 R4 (config-if) #no shut R5 (config) #int f0/0 R5 (config-if) #ip add 192.168.105.1 255.255.255.0 R5 (config-if) #no shut R5 (config) #int s0/0 R5 (config-if) #ip add 192.168.4.2 255.255.255.0 R5 (config-if) #no shut R5 (config) #int s0/1 R5 (config-if) #ip add 192.168.5.1 255.255.255.0 R5 (config-if) #no shut R6 (config) #int f0/0 R6 (config-if) #ip add 192.168.106.1 255.255.255.0 OSPF (Open Shortest Path First) Part- III R6 (config-if) #no shut R6 (config) #int s0/0 R6 (config-if) #ip add 192.168.5.2 255.255.255.0 R6 (config-if) #no shut R6 (config) #int loo R6 (config-if) #ip add 172.60.1.1 255.255.255.0 R6 (config) #int loo R6 (config-if) #ip add 172.60.2.1 255.255.255.0 R6 (config) #int loo R6 (config-if) #ip add 172.60.3.1 255.255.255.0 R6 (config) #int loo R6 (config-if) #ip add 172.60.4.1 255.255.255.0 R6 (config) #int loo R6 (config-if) #ip add 172.60.5.1 255.255.255.0 R7 (config) #int fa0/0 R7 (config-if) #ip add 192.168.107.1 255.255.255.0 R7 (config-if) #no shut R7 (config) #int s0/0 R7 (config-if) #ip add 192.168.6.2 255.255.255.0 R7 (config-if) #no shut R7 (config) #int loo R7 (config-if) #ip add 172.70.1.1 255.255.255.0 R7 (config) #int loo R7 (config-if) #ip add 172.70.2.1 255.255.255.0 R7 (config) #int loo R7 (config-if) #ip add 172.70.3.1 255.255.255.0 R7 (config) #int loo R7 (config-if) #ip add 172.70.4.1 255.255.255.0 R7 (config) #int loo R7 (config-if) #ip add 172.70.5.1 255.255.255.0 R7#ping 192.168.6.1 R7#ping 192.168.6.1 Successful ISP (config) #int fa0/0 ISP (config-if) #ip add 102.1.1.1 255.255.255.0 ISP (config-if) #no shut ISP (config) #int s0/0 ISP (config-if) #ip add 101.1.1.1 255.255.255.0 OSPF (Open Shortest Path First) Part- III ISP (config-if) #no shut OSPF Configuration R1 (config) #int fa0/0 R1 (config-if) #ip os 100 area R1 (config) #int s0/0 R1 (config-if) #ip os 100 area R2 (config) #int fa0/0 R2 (config-if) #ip os 100 area R2 (config) #int s0/0 R2 (config-if) #ip os 100 area R2 (config) #int s0/1 R2 (config-if) #ip os 100 area R3 (config) #int fa0/0 R3 (config-if) #ip os 100 area R3 (config) #int s0/0 R3 (config-if) #ip os 100 area R3 (config) #int s0/1 R3 (config-if) #ip os 100 area R3 (config-if) #router ei 100 R3 (config-router) #no auto-summary R3 (config-router) #network 192.168.6.0 R4 (config) #int fa0/0 R4 (config-if) #ip os 100 area R4 (config) #int s0/0 R4 (config-if) #ip os 100 area R4 (config) #int s0/1 R4 (config-if) #ip os 100 area R5 (config) #int s0/0 R5 (config-if) #ip os 100 area R5 (config-if) #router ei 200 R5 (config-router) #no auto-summary R5 (config-router) #network 192.168.105.0 R5 (config-router) #network 192.168.5.0 R6 (config-if) #router ei 200 R6 (config-router) #no auto-summary OSPF (Open Shortest Path First) Part- III R6 (config-router) #network 0.0.0.0 R7 (config-if) #router ei 200 R7 (config-router) #no auto-summary R7 (config-router) #network 0.0.0.0 R3#sh ip route Now we want to communicate OSPF domain with ei 100 domain For that we will perform here redistribution R3 (config) #router os 100 R3 (config-router) #redistribute ei 100 subnets metric-type R3 (config-router) #router ei 100 R3 (config-router) #redistribute os 100 metric 1 1 We performed here two way of redistribution R1#ping 172.70.1.1 source fa0/0 Successful R1#sh ip route os Here we can see two types of routes First is intra area (which belongs to its area) OIA means Inter area E – External Area Now our task is configure area is as stub R1 (config) #router os 100 R1 (config-router) #area stub R2 (config) #router os 100 R2 (config-router) #area stub Requirements for stub area Virtual links are not allowed Area can’t be stub All the routers must be agree that we are a part of stub area If you are configuring R1, that area is stub so it is your duty you have to configure R2 that area is stub, if you will not configure, neighborship will not established OSPF (Open Shortest Path First) Part- III R1#sh ip route os R1#ping 172.70.1.1 source fa0/0 Successful R2 #sh ip route It contains entire ospf routes Now we will see totally stub, it filters the external routes and inter area routes, and places them as a default route R2 (config) #router os 100 R2 (config) #area stub no-summary R1#sh ip route os We can see small routing table here R5#sh ip route os R5 (config) #router os 100 R5 (config-router) #area stub R4 (config) #router os 100 R4 (config-router) #area stub no-summary R5#sh ip route os R5#ping 192.168.101.1 source s0/0 successful Now we will perform redistribution on R5 R5 (config) #router os 100 R5 (config-router) #redistribute ei 200 subnets metric-type R5 (config) #router ei 200 R5 (config-router) #redistribute os 100 metric 1 1 R3#sh ip route Here we cannot see 172.60.0.0 routes Now we will configure NSSA First we need to remove this command here R4 (config) #router os 100 R4 (config-router) #no area stub OSPF (Open Shortest Path First) Part- III R5 (config) #router os 100 R5 (config-router) #no area stub If we will remove stub command totally stub command will removed automatically R4 (config) #router os 100 R4 (config-router) #area nssa R5 (config) #router os 100 R5 (config-router) #area nssa R3#sh ip route Here we can see O E – 172.60.1.0 to R7#sh ip route ei Here we can see this route 172.60.1.0 to R4#sh ip route os It contain 70 series here 172.70.0.0 R5#sh ip route os It doesn’t contain the route of 172.70.0.0 R5#ping 172.70.1.1 not successful Now we will configure Totally NSSA on R4 R4 (config) #router os 100 R4 (config-router) #area nssa no-summary default-information-originate R5#ping 172.70.1.1 successful R6#ping 172.70.1.1 successful R6#ping 172.70.1.1 source fa0/0 successful OSPF (Open Shortest Path First) Part- III Now we will remove stub and totally stub from area R1 (config) #router os 100 R1 (config-router) #no area stub R2 (config) #router os 100 R2 (config-router) #no area stub Now here we will provide the internet access on all routers R3 is directly connected with the ISP router R3#ping 101.1.1.1 successful R3#ping 102.1.1.1 not successful Now we will create default route on R3 towards ISP R3 (config) #Ip route 0.0.0.0 0.0.0.0 101.1.1.1 R3#ping 102.1.1.1 successful R3#ping 101.1.1.1 successful Here R3 is able to communicate with the ISP R3#ping 102.1.1.1 source fa0/0 not successful R3 (config) #int s0/0 R3 (config-if) #ip nat inside R3 (config-if-nat) #int s0/1 R3 (config-if) #ip nat inside R3 (config-if-nat) #int s0/2 R3 (config-if) #ip nat inside R3 (config-if-nat) #int s0/3 R3 (config-if) #ip nat outside R3 (config-if-nat) #int f0/0 R3 (config-if) #ip nat inside R3 (config) #access-list 10 permit any R3 (config-access) #ip nat inside source list 10 int s0/3 overload R3#ping 102.1.1.1 source fa0/0 successful R3#sh ip nat translation Now we will provide the internet access to all areas R2#sh ip route It hasn’t any default route so it can’t communicate with the internet OSPF (Open Shortest Path First) Part- III R3 (config) #router os 100 R3 (config-router) #default-information originate always R2 #sh ip route Here we can see a default route O*E2 0.0.0.0/0 R1#piing 102.1.1.1 source fa0/0 successful R6#ping 102.1.1.1 source loo1 successful R7#ping 102.1.1.1 source loo1 not successful R7#sh ip route It doesn’t contain default route R3 (config) #ip summary-address ei 100 0.0.0.0 0.0.0.0 R3#sh ip route D* 0.0.0.0 / Now we can see here default route R7#ping 102.1.1.1 source loo successful There are three ways to generate default route in Eigrp Redistribution Summarization IP default network Now here we will check LSAs R1#sh ip ospf database  Router LSA Router LSA contains router ID of a router It is sent within an area Router ID (i) (ii) (iii) Highest Loop Back Highest Up Physical int IP Router ID Here we can see two router ID OSPF (Open Shortest Path First) Part- III 192.168.101.1 192.168.102.1  Network LSA It contains DR router ID and it is sent by DR DR & BDR are elected only in Broadcast and non-broadcast multi-access network We have point to point link, so DR and BDR is not available We will make forcefully it broadcast segment via command R1 (config) #int s0/0 R1 (config-if) #ip os network broadcast R2 (config) #int s0/0 R2 (config-if) #ip os network broadcast R1#sh ip os neighbor R1#debug ip os adj R1#clear ip os process Yes R1#un all We can see first is Down state Attempt state only happens in frame-realy To check init we need to go on R2 R2#debug ip os adj R2#clear ip process Yes R2#un all Here we can see init  Network LSA Contain DR ID For DR (i) Highest router Priority (ii) Highest router ID Router is DR here OSPF (Open Shortest Path First) Part- III  Summary LSA When a route of one area goes to another area they go as summary SLA It is sent by ABR Here R2 is ABR  AS LSA It contains ASBR router ID & it is sent by ABR R3 is ASBR here  External LSA It contains External routes It is sent by ASBR 172.70 series sending R3 172.60 series sending R4  Group Membership LSA – It is not supported by cisco  NSSA– It allows an ASBR to send external area through stub area to backbone area using LSA R5#sh ip os database R4#sh ip os database R3#sh ip os database