What metric value is assigned by default when OSPF route is redistributed into EIGRP?

Transcription

1 What metric value is assigned by default when OSPF route is redistributed into EIGRP? A. 90 B. 110 C. 20 D. 15 E. Infinity Answer: E metric-value - (Optional) A parameter that specifies the EIGRP seed metric, in the order of bandwidth, delay, reliability, load, and maximum transmission unit (MTU), for the redistributed route. When redistributing into EIGRP (and all protocols other than OSPF and BGP), if this value is not specified and no value is specified using the default-metric router configuration command, the default metric is 0. For EIGRP (and all protocols other than IS-IS), the default metric of 0 is interpreted as infinity, and routes will not be redistributed. The metric for EIGRP is calculated based only on bandwidth and delay by default

2 Refer to the exhibit. Routers R1 and R2 have been configured to operate with OSPF. Routers R1 and R3 have been configured to operate with RIP. After configuring the redistribution between OSPF and RIP on R1, no OSPF routes are distributed into RIP. What should be done to correct this problem? R1(config)#router rip R1(config-router)#redistribute ospf 1 A. The redistribution command should be reentered with the match route-type parameter included. B. The redistribution command should be reentered with the route-map map-tag parameter included. C. The redistribution command should be reentered with the metric metric-value parameter included. D. Routes will first need to be distributed into another protocol, and then into RIP. Answer: C Use the redistribute protocol [process-id] [match route-type] [metric metric-value] [route-map map-tag] router configuration command to redistribute routes into RIP. metric-value - A parameter used to specify the RIP seed metric for the redistributed route. When redistributing into RIP (and all protocols other than OSPF and BGP), if this value is not specified and no value is specified using the default-metric router configuration command, the default metric is 0. For RIP (and all protocols other than IS-IS), the default metric of 0 is interpreted as infinity, and routes will not be redistributed. The metric for RIP is hop count. In our case we have to use for example, following commands: R1(config)#router rip R1(config-router)#redistribute ospf 1 metric

3 Which two routing protocols require a metric to be configured when redistributing routes from other protocols? (Choose two.) A. RIP B. OSPF C. EIGRP D. IS-IS E. BGP Answer: A, C When redistributing into RIP and EIGRP metric must be set manually via configuration command. If metric is not configured, by default is interfpreted as infinity and routes ain t gonna be redistributed. When redistributing into OSPF default metric value is 20. Example: EIGRP router eigrp 1 redistribute ospf 1 metric redistribute rip metric network RIP router rip version 2 redistribute eigrp 1 metric 2 redistribute ospf 1 metric 3 network More on: Link

4 By default, which statement is correct regarding the redistribution of routes from other routing protocols into OSPF? A. They will appear in the OSPF routing table as type E1 routes. B. They will appear in the OSPF routing table as type E2 routes. C. Summarized routes are not accepted. D. All imported routes will be automatically summarized when possible. E. Only routes with lower administrative distances will be imported. Answer: B The point of this question is OSPF route redistribution. When redistributing routes from other routing protocols into OSPF, there is a default cost value 20 displaying in the OSPF routing table, as type E2 route by default

5 A network administrator is troubleshooting a redistribution of OSPF routes into RIP. Given the exhibited commands, which statement is true? router rip network redistribute ospf 5 router ospf 5 network area 0 A. Redistributed routes will have an external type of 1 and a metric of 1. B. Redistributed routes will have an external type of 2 and a metric of 20. C. Redistributed routes will maintain their original OSPF routing metric. D. Redistributed routes will have a default metric of 0 and will be treated as reachable and advertised. E. Redistributed routes will have a default metric of 0 but will be treated as unreachable and not advertised. Answer: E Use the redistribute protocol [process-id] [match route-type] [metric metric-value] [route-map map-tag] router configuration command to redistribute routes into RIP. metric-value - A parameter used to specify the RIP seed metric for the redistributed route. When redistributing into RIP (and all protocols other than OSPF and BGP), if this value is not specified and no value is specified using the default-metric router configuration command, the default metric is 0. For RIP (and all protocols other than IS-IS), the default metric of 0 is interpreted as infinity, and routes will not be redistributed. The metric for RIP is hop count. Note: When redistributing into RIP, the default metric is infinity except when redistributing a static route (including a default static route defined using the ip route command) or connected route. In these cases, the default metric is 1. In our case is used: router rip redistribute ospf 5 We can see that metric parameter is missing. So, default metric is

6 Refer to the exhibit. The network administrator is trying to configure mutual redistribution between EIGRP and OSPF. Autosummarization in EIGRP 100 AS is disabled. After adding OSPF configuration to router B1, the network administrator checked the routing table of router B2, but none of the EIGRP routes appeared there. To redistribute the EIGRP AS 100 routes into OSPF, which command should be added, or edited, on router B1 under router ospf 10? B2#show ip route /24 is subneted, 1 subnets C is directly connected, Ethernet1/ /24 is subnetted, a subnets C is directly connected, FastEthernet0/1 C /24 is directly connected, FastEtherent0/0 A. redistribute eigrp 100 metric-type 1 B. redistribute eigrp 100 subnets C. no auto-summary D. area 0 range Answer: B Redistribution is capability of boundary routers connecting different routing domains (OSPF and RIP, or OSPF and EIGRP, or EIGRP and RIP, or ) to exchange and advertise routing information between those routing domains (autonomous systems). First we have to explain few parameters that are used in redistribute command:

7 metric - is parameter that specifies OSPF seed metric used for redistributed route. When redistributing into OSPF default metric is 20 (except for BGP where default metric is 1). Metric for OSPF is cost. type value is OSPF parameter that specifies external link type associated with external route advertised into OSPF routing domain. This value can be 1 for type 1 external routes or 2 for type 2 external routes. Default is 2. subnets is OSPF parameter that specifies that subnetted routes should also be redistributed. Only routes that are not subnetted are redistributed if the subnet keyword is not specified. Let see the first command - redistribute eigrp 100 metric-type 1: Here we don t have subnets parameter. This means that subnetted networks are not redistributed. We got two networks in EIGRP 100 that are subnetted ( and ). We need to redistribute all routes from EIGRP 100, so we can t use this command. Let see the second command - redistribute eigrp 100 subnets: Here we have subnets parameter. This means that subnetted networks also will be redistributed together with not subnetted routes. We got two networks in EIGRP 100 that are subnetted ( and ) and one that is not subnetted /24. That is the reason why we use this command for redistribution from EIGRP 100 to OSPF

8 A network administrator is troubleshooting a redistribution of RIP routes into OSPF. Given the exhibited configuration commands, which statement is true? router rip network router ospf 5 network area 0 redistribute rip A. Redistributed routes will be tagged as external type 1 (E1) with a metric of 30. B. Redistributed routes will be tagged as external type 2 (E2) with a metric of 20. C. Redistributed routes will maintain their original RIP routing metric. D. Redistributed routes will have a default metric of 0 and will be treated as unreachable and not advertised. E. Redistributed routes will have a default metric of 0 but will not be treated as reachable and will be advertised. Answer: B When redistributing into OSPF default metric is 20 (except for BGP where default metric is 1). Metric for OSPF is cost. type value is OSPF parameter that specifies external link type associated with external route advertised into OSPF routing domain. This value can be 1 for type 1 external routes or 2 for type 2 external routes. Default is 2. More on: Link

9 Refer to the exhibit. Which statement is true? hostname RTA <output omitted> router ospf 1 redistribute rip subnets network area 1 area 1 nssa hostname RTA <output omitted> router ospf 1 summary-address network area 0 network area 1 area 1 nssa A. RTA will redistribute the RIP routers into the NSSA as type 7 LSAs. RTB will translate the type 7 LSAs into type 5 LSAs and flood them throughout the OSPF backbone. B. RTA will redistribute the RIP routers into the NSSA as type 7 LSAs. RTB will flood the type 7 LSAs throughout the backbone. C. RTA will redistribute the RIP routers into the NSSA as type 5 LSAs. RTB will flood the type 5 LSAs throughout the backbone. D. RTA will redistribute the RIP routers into the NSSA as type 5 LSAs. RTB will translate the type of 5 LSAs unto type 7 LSAs and flood them throughout the OSPF backbone. E. RTA will not redistribute the RIP routers into the NSSA. Answer: A Redistribution into an NSSA area creates a special type of LSA known as type 7, which can exist only in an NSSA area. An NSSA ASBR generates this LSA, and an NSSA ABR translates it into a type 5 LSA, which gets propagated into the OSPF domain. Type 7 LSAs have a propagate (P) bit in the LSA header to prevent propagation loops between the NSSA and the backbone area. Type 7 LSAs are the same format as type 5 LSAs

10 Which three steps are most helpful in verifying proper route redistribution? (Choose three.) A. On the routers not performing the route redistribution, use the show ip route command to see if the redistributed routes show up. B. On the ASBR router performing the route redistribution, use the show ip protocol command to verify the redistribution configurations. C. On the ASBR router performing the route redistribution, use the show ip route command to verify that the proper routes from each routing protocol are there. D. On the routers not performing the route redistribution, use the show ip protocols command to verify the routing information sources. E. On the routers not performing the route redistribution, use the debug ip routing command to verify the routing updates from the ASBR. Answer: A, B, C During verification of the process of redistribution you have to use command show ip route on ASBR router and on the routers in the routing domain where redistribution is done. Command is useful to check which routes are redistributed. - show ip protocols command lists the protocol that is being redistributed in the routing domain. This command is useful on the router where redistribution is performed (ASBR router)