CCNP ENARSI lab 11 of 35
Mutual redistribution, administrative distance and loop prevention
Join an OSPF domain and an EIGRP domain at two routers, see how administrative distance and feedback create suboptimal paths and loops, and fix them for good with route tags and an administrative distance change.
Run this lab
It needs Lite: its 4 nodes are set to 4 vCPU and 2,048 MB in total. That fits the free demo too.
In your workspace: Shared, then CCNP ENARSI 300-410 guided labs, then 11 - Mutual redistribution administrative distance and loop prevention
- Level
- Advanced
- Time
- About 80 minutes
- Nodes need
- 4 vCPU, 2,048 MB
- Smallest plan
- Lite
The scenario
Ravensworth Foods bought a factory whose network runs EIGRP AS 100 (R4, the plant router, plus two routers that now also connect to head office). Head office runs OSPF area 0 (R1). Two routers, R2 and R3, sit on the boundary and run both protocols, so the domains can be joined at two points for redundancy. The plant also has a control network, 192.168.44.0/24, which R4 redistributes into EIGRP as an external route.
Join the domains at both points, then deal with what goes wrong when routes can loop back through the second boundary router.
| Device | Interface | Address | Domain |
|---|---|---|---|
| R1 | Gi0/0 / Gi0/1 | 10.0.12.1 / 10.0.13.1 /24 | OSPF |
| R1 | Lo1 | 10.1.1.1/24 (HQ LAN) | OSPF |
| R2 | Gi0/0 / Gi0/1 | 10.0.12.2/24 (OSPF) / 172.16.24.2/24 (EIGRP) | both |
| R3 | Gi0/0 / Gi0/1 | 10.0.13.3/24 (OSPF) / 172.16.34.3/24 (EIGRP) | both |
| R4 | Gi0/0 / Gi0/1 | 172.16.24.4 / 172.16.34.4 /24 | EIGRP |
| R4 | Lo1 | 172.16.4.1/24 (plant LAN) | EIGRP internal |
| R4 | Lo44 | 192.168.44.1/24 (control network) | EIGRP external |
| R1–R3 | Lo0 | 10.255.0.n/32 | OSPF |
Topology: a square. R1 (OSPF) on the left, R4 (EIGRP) on the right, R2 and R3 between them.
What you’ll practise
- Redistribute between OSPF and EIGRP with correct seed metrics and the subnets keyword
- Explain how administrative distance decides between the same prefix learned from two protocols
- Predict the suboptimal routing and feedback that two redistribution points create
- Prevent route feedback with tags set on redistribution and denied on the way back
- Fix administrative-distance problems with distance ospf external
The tasks
- Look at each domain alone
- Redistribute at R2 only
- Add the second redistribution point and find the problem
- Stop route feedback with tags
- Fix the administrative-distance problem
- Test the joined network
The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.
Topology and devices
The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.
Every link, as text
- R1
Gi0/0to R2Gi0/0 - R1
Gi0/1to R3Gi0/0 - R2
Gi0/1to R4Gi0/0 - R3
Gi0/1to R4Gi0/1
| Node | Device | Image in Add Node | Set to |
|---|---|---|---|
| R1 | Cisco IOSv | vios-adventerprisek9-m.spa.159-3.m9 | 1 vCPU, 512 MB |
| R2 | Cisco IOSv | vios-adventerprisek9-m.spa.159-3.m9 | 1 vCPU, 512 MB |
| R3 | Cisco IOSv | vios-adventerprisek9-m.spa.159-3.m9 | 1 vCPU, 512 MB |
| R4 | Cisco IOSv | vios-adventerprisek9-m.spa.159-3.m9 | 1 vCPU, 512 MB |
How to open this lab
Sign in to your workspace at
lab.cloudlabbox.com.In File Manager, open Shared, then the folder
CCNP ENARSI 300-410 guided labs.Open
11 - Mutual redistribution administrative distance and loop preventionand start its nodes, then open Lab Tasks for the scenario and the steps.
The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.
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CloudLabBox is independent of Cisco. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.