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Multi-vendor troubleshooting lab 1 of 12

OSPF between IOS, Junos, EOS and RouterOS

Four vendors share one OSPF ring, and each link has a different problem: an MTU mismatch, a network-type mismatch, different timers and a mismatched authentication key ID. Read each vendor's symptoms, fix every link and normalise the costs that each vendor picks for itself.

Run this lab

It needs Lite: its 5 nodes are set to 6 vCPU and 7,424 MB in total. That fits the free demo too.

In your workspace: Shared, then Multi-vendor interoperability and troubleshooting guided labs, then 01 - OSPF between IOS Junos EOS and RouterOS

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Level
Intermediate
Time
About 75 minutes
Nodes need
6 vCPU, 7,424 MB
Smallest plan
Lite

The scenario

Larkfield Freight has grown by buying two regional hauliers, and its core is now a ring of four vendors: Cisco at Leeds head office, a Juniper SRX at the Hull depot, an Arista switch in the data centre and a MikroTik router at the Goole depot. The links were patched at the weekend and OSPF was enabled everywhere, but the Goole LAN can't reach anything.

Each of the four links has its own problem, and each is the kind that appears only between vendors. Your job is to compare each link with the design standard below and fix the side that breaks it.

DeviceInterfaceAddressConnects to
R1Gi0/010.0.12.1/30SRX1 ge-0/0/0 (link A)
R1Gi0/110.0.41.1/30CHR1 ether2 (link D)
R1Loopback010.255.0.1/32Router ID
SRX1ge-0/0/0.010.0.12.2/30R1 Gi0/0 (link A)
SRX1ge-0/0/1.010.0.23.1/30EOS1 Ethernet1 (link B)
SRX1lo0.010.255.0.2/32Router ID
EOS1Ethernet110.0.23.2/30SRX1 ge-0/0/1 (link B)
EOS1Ethernet210.0.34.1/30CHR1 ether1 (link C)
EOS1Loopback010.255.0.3/32Router ID
CHR1ether110.0.34.2/30EOS1 Ethernet2 (link C)
CHR1ether210.0.41.2/30R1 Gi0/1 (link D)
CHR1ether310.40.0.1/24Goole LAN
CHR1loopback10.255.0.4/32Router ID
H1eth010.40.0.10/24Gateway 10.40.0.1
Design standardValue
Area0 (0.0.0.0) on every link
Network typePoint-to-point on every ring link
TimersHello 10 s, dead 40 s, the OSPF default
IP MTU1500 on every ring link
Link D authenticationMD5, key ID 10, key Larkfield-Core1
Cost10 on every ring link, in both directions

What you’ll practise

  • Read OSPF neighbour state on Cisco IOS, Junos, Arista EOS and RouterOS
  • Recognise an MTU mismatch from a neighbour stuck in ExStart or Exchange
  • Find a network-type mismatch that leaves one end at Init and the other end listing nobody
  • Find a timer mismatch that hides a neighbour completely
  • Match MD5 authentication key IDs across vendors
  • Explain why OSPF cost needn't match for an adjacency, and set one cost on all four vendors

The tasks

  1. Give H1 its address
  2. Read the symptoms before you touch anything
  3. Link A, stuck in ExStart
  4. Link B, Init on one side and nothing on the other
  5. Link C, no neighbour at all
  6. Link D, authentication key IDs
  7. Prove the ring, then normalise cost

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.

Topology of OSPF between IOS Junos EOS and RouterOS5 nodes, 5 links. Every link is listed as text below the diagram.R1SRX1EOS1CHR1H1ether3eth0ge-0/0/1Ethernet1ether2Gi0/1Gi0/0ge-0/0/0Ethernet2ether1
5 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 Gi0/0 to SRX1 ge-0/0/0
  • SRX1 ge-0/0/1 to EOS1 Ethernet1
  • EOS1 Ethernet2 to CHR1 ether1
  • CHR1 ether2 to R1 Gi0/1
  • CHR1 ether3 to H1 eth0
Nodes in OSPF between IOS, Junos, EOS and RouterOS, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R1Cisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
SRX1Juniper vSRX NextGen templatevsrxng-23.4R2-S3.92 vCPU, 4,096 MB
EOS1Arista vEOSveos-4.33.1.1F1 vCPU, 2,048 MB
CHR1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
H1Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder Multi-vendor interoperability and troubleshooting guided labs.

  3. Open 01 - OSPF between IOS Junos EOS and RouterOS and 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 Arista Networks, Cisco, CompTIA, Fortinet, HPE, Juniper Networks and MikroTik. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.