350-501 · Question #389
Refer to the exhibit. A network operator working for a telecommunication company with an employee ID: 4350:47:853 must implement an IGP solution based on these requirements: - Subnet 10.50.10.0…
The correct answer is B. Apply a route policy to redistribute 10.50.20.0 from ISIS-L2 to OSPF Area 0 at a higher cost. D. Apply a route policy to redistribute 10.50.10.0 from OSPF Area 0 to ISIS-L2 at a lower cost. To achieve specific traffic steering for 10.50.10.0 via OSPF and 10.50.20.0 via IS-IS with OSPF backup, R5 must redistribute 10.50.10.0 from OSPF to ISIS with a lower cost and redistribute 10.50.20.0 from ISIS to OSPF with a higher cost.
Question
Refer to the exhibit. A network operator working for a telecommunication company with an employee ID: 4350:47:853 must implement an IGP solution based on these requirements:
- Subnet 10.50.10.0 traffic must exit through the R1 router to connect
with the Syslog server.
- Subnet 10.50.20.0 traffic must exit through the R2 router to connect
with the NTP server.
- In case of link failure between R2 and R4, traffic must be routed via
R1 and R3. Which two configurations must be implemented on R5 to meet these requirements? (Choose two.)
Exhibit
Options
- AApply a route policy to redistribute 10.50.0.0 prefixes in OSPF to ISIS and ISIS to OSPF.
- BApply a route policy to redistribute 10.50.20.0 from ISIS-L2 to OSPF Area 0 at a higher cost.
- CEnable a route policy to advertise 10.50.20.0 in ISIS-L2 at a higher cost.
- DApply a route policy to redistribute 10.50.10.0 from OSPF Area 0 to ISIS-L2 at a lower cost.
- EEnable a route policy to advertise 10.50.10.0 in OSPF Area 0 at a low cost.
How the community answered
(46 responses)- A4% (2)
- B61% (28)
- C24% (11)
- E11% (5)
Why each option
To achieve specific traffic steering for 10.50.10.0 via OSPF and 10.50.20.0 via IS-IS with OSPF backup, R5 must redistribute 10.50.10.0 from OSPF to ISIS with a lower cost and redistribute 10.50.20.0 from ISIS to OSPF with a higher cost.
This option is too general; redistributing `10.50.0.0` without specific cost adjustments for `10.50.10.0` and `10.50.20.0` will not guarantee the desired primary and backup paths.
To ensure 10.50.20.0 traffic primarily exits via R2 (ISIS) and uses R1/R3 (OSPF) as a backup during link failure, R5 must redistribute the ISIS-learned 10.50.20.0 prefix into OSPF with a higher metric or cost, making it less preferred than the direct ISIS path.
Advertising `10.50.20.0` in ISIS-L2 at a higher cost would make the ISIS path for that subnet less preferred, contradicting the requirement for R2 (ISIS) to be the primary exit for this traffic.
To ensure 10.50.10.0 traffic exits via R1 (OSPF), R5, being the redistribution point, should redistribute the OSPF-learned 10.50.10.0 prefix into ISIS with a lower metric or cost, making the path through R1 more attractive to ISIS routers.
Advertising `10.50.10.0` in OSPF Area 0 at a low cost is an internal OSPF optimization, but it does not directly control how the route is redistributed into ISIS to influence its path selection for traffic originating from the ISIS domain.
Concept tested: Route redistribution with metric manipulation
Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/configuration/15-mt/iro-ospf-15-mt-book/iro-redist.html
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