1. A network engineer is implementing redistribution of two routing protocols across a network topology. Under which situation would there be minimal concern of network visibility being hidden from the destination routing source?
- when there is only one point of redistribution between two sources
- while performing multipoint redistribution between multiple protocols
- while performing multipoint redistribution between a single routing protocol of varying process-id or autonomous-system number
- when there are at least two points of redistribution in the network
Explanation: While performing redistribution between varying routing protocols, network visibility is lost or hidden from the destination routing source. However, this is not an issue when there is only one point of redistribution between two sources.
2. A boundary router is running both OSPF and BGP. What is required for the redistribution process to successfully redistribute source information into the BGP process?
- The BGP process must have a route-map configured in order to set a metric for successful redistribution.
- The OSPF process must use a default metric as the routing source redistributing information into the BGP process.
- The source information must be filtered using an ACL to specify only NSSA routes during the redistribution process for BGP.
- The route to be redistributed must have a current entry in the routing table from the source routing protocol.
Explanation: In order for any source information to be redistributed into a destination routing process, that information must currently exist within the source routing protocol RIB. If the route is removed from the source routing protocol RIB, the information is no longer able to be redistributed into the destination routing process.
3. Refer to the exhibit. A network engineer has issued the exhibited commands on a boundary router. What is the result of these commands?
- The internal administrative distance for EIGRP AS 100 has been changed to 255.
- The default seed metric for EIGRP AS 100 has been changed to 255.
- The external administrative distance for EIGRP AS 100 has been configured to not install external routes in the RIB.
- The EIGRP AS 100 process has been configured to install external routes in the RIB with a metric between 100 and 255.
Explanation: The EIGRP configuration command distance eigrp ad-internal ad-external is used to modify the default administrative distance on IOS routers. The valid values for the AD are between 1 and 255; a value of 255 stops the installation of the route into the routing information base (RIB).
4. Which two statements define the behavior of a seed metric between dissimilar routing protocols? (Choose two.)
- It creates a distribute-list in global configuration mode.
- It uses the default-metric command.
- It creates an access-list in global configuration mode.
- It defines a prefix list in global configuration mode.
- It applies a route map configuration to the redistribute command.
Explanation: There are three ways to define a seed metric when working with dissimilar routing protocols:
- Uses the default-metric command.
- Uses the metric parameter with the redistribute command.
- Applies a route map configuration to the redistribute command.
5. Which keyword is not supported when redistributing IPv6 from a source to a destination routing protocol?
- match
- route-map
- subnets
- metric
Explanation: The subnets keyword is not an option with IPv6 routing protocols because the concepts classful and classless do not exist with IPv6.
6. A network engineer is troubleshooting suboptimal routing on a network that may utilize redundant route redistribution. What should the engineer verify first?
- The engineer should verify the route tags being implemented within the redistribution process on the boundary router.
- The engineer should verify the default seed metrics being used within the redistribution process.
- The engineer should verify the subnets keyword being used within the redistribution process.
- The engineer should verify that mutual redistribution is occurring at multiple points in the network.
Explanation: When troubleshooting suboptimal routing caused by redistribution, a network engineer must be able to recognize that mutual redistribution is occurring at multiple points in the network.
7. A network engineer is reviewing the network topology and verifying route entries of a specific boundary router. What is the administrative distance of a route that was sourced as a directly connected network, advertised locally through RIP, redistributed into EIGRP, and then redistributed into OSPF?
- 170
- 90
- 110
- 120
- 1
Explanation: If there is no manual configuration using a distance command or route-map, the AD value of a source route will be modified by the destination routing process according to the default AD used by that routing process. OSPF is the last routing protocol to have source information redistributed into it and it has a single AD value of 110.
8. While implementing redistribution in a network topology, what is the function of the boundary router?
- to keep broadcasts contained within a layer 2 segment
- to separate the public resources from the private resources
- to connect two or more routing domains
- to limit end-to-end connectivity by modifying IP headers in outgoing packets
Explanation: While utilizing redistribution in a network topology, a boundary router is the router that connects two or more routing domains and this router will be the point of redistribution.
9. Refer to the exhibit. A network engineer is troubleshooting a configuration for EIGRP and OSPF redistribution. Why is the OSPF process not receiving the redistributed EIGRP routes?
- The EIGRP routing protocol is not activated on interface Gi0/0/1.
- The OSPF routing protocol is using an unreachable metric.
- The EIGRP routing protocol is not configured for mutual redistribution.
- The OSPF routing protocol has an incorrect administrative distance configured.
Explanation: When troubleshooting redistribution, it is important to verify that the source routing protocol is configured correctly and has learned the routes before attempting to redistribute them. Because of a typo in the EIGRP 100 network command, EIGRP is not activated on the Gig0/0/1 interface.
10. A network engineer is verifying the successful redistribution of EIGRP routes into an OSPF routing process. What should the engineer do on the boundary router to verify the reachable IPv4 addresses on the neighbor EIGRP routers?
- Issue the show ip eigrp neighbors command.
- Issue the show cdp neighbors command.
- Issue the show cdp neighbors detail command.
- Issue the show ipv6 eigrp topology command.
Explanation: When troubleshooting EIGRP and OSPF mutual redistribution, it is important to verify that the source routing protocol is configured correctly. In order to verify the IP addresses configured on the physical interfaces of a neighboring router, the show cdp neighbors detail command should be used.
11. A reachability issue is reported by users in a network topology that utilizes OSPFv2 and redistribution. What is the first step that a junior administrator should take in troubleshooting this issue?
- Verify the loss of reachability using a ping with a source IP and destination IP set.
- Verify the loss of the destination network in the routing table of the boundary router.
- Verify the loss of the network entry in the OSPF database on the boundary router.
- Verify the OSPF neighbor adjacencies that exist on the boundary router.
Explanation: The first step that should be taken when approached with a user ticket is to verify the problem exists and attempt to locate the point of failure. A ping or traceroute is the best way to start troubleshooting connectivity concerns.
“Do I Know This Already?” Quiz Answers:
1. Which of the following are methods that can be used to solve routing issues caused by multipoint redistribution? (Choose all that apply.)
- Modify the seed metrics of the redistributed routes.
- Modify the administrative distances of redistributed routes.
- Tag routes as they are redistributed and then deny them from being redistributed back into the originating routing source.
- Modify the metric used to reach the boundary routers.
2. Which of the following methods can be used to solve suboptimal routing issues caused by redistribution?
- Modify the seed metrics of the redistributed routes.
- Modify the administrative distances of redistributed routes.
- Redistribute only classless networks.
- Modify the metrics of the routes before redistribution.
3. Which of the following is true?
- The EIGRP command distance 165 10.1.1.1 0.0.0.0 changes the AD to 165 for all EIGRP routes learned from neighbor 10.1.1.1.
- The EIGRP command distance 165 10.1.1.1 0.0.0.0 changes the AD to 165 for the EIGRP learned route 10.1.1.0/24.
- The EIGRP command distance 165 10.1.1.1 0.0.0.0 changes the AD to 165 for internal EIGRP routes learned from neighbor 10.1.1.1.
- The EIGRP command distance 165 10.1.1.1 0.0.0.0 changes the AD to 165 for external EIGRP routes learned from neighbor 10.1.1.1.
4. What must be true for a route from one routing source to be redistributed into a different routing source?
- The routing sources must have similar metrics.
- The routing sources must have similar administrative distances.
- The route must be in the routing table on the router performing redistribution.
- The route must be a directly connected route on the router performing redistribution.
5. Which of the following routing protocols have a default seed metric of unreachable? (Choose two.)
- RIP
- EIGRP
- OSPF
- BGP
6. Which of the following routing protocols has a default seed metric of 20?
- RIPng
- EIGRP for IPv6
- OSPFv3
- BGP
7. When redistributing, you have four options for the seed metric: accepting the default value, specifying it with the default-metric command, using the metric option with the redistribute command, and using a route map. If all four of these are configured with different values, which will be preferred?
- Default values
- default-metric command
- Metric option with the redistribute command
- Route map attached to the redistribute command
8. Which option is mandatory when redistributing OSPF routes into EIGRP?
- metric
- metric type
- subnets
- match
9. Which option is mandatory when redistributing classless networks into OSPF?
- metric
- metric type
- subnets
- match
10. Which of the following is not included when redistributing from one IPv6 routing protocol into another IPv6 routing protocol?
- A prefix
- A seed metric
- A directly connected route participating in the routing process
- An administrative distance
11. During redistribution that uses route maps, what occurs to a route that matches a deny entry in the route map?
- It is redistributed with default values.
- It is redistributed with the values in the set clause.
- It is redistributed only if there is a routing table entry for it.
- It is not redistributed.