BGP Route Reflector Scaling
Two route reflectors, two established sessions, and exactly one path. Find out why the second one is not reflecting, live, right below.
Symptom
Route reflectors in place of a full iBGP mesh: clients, non-clients, and the cluster-ID and originator-ID loop checks.
Your mission
Inspect, recover, then verify
Format
Cisco IOS CLI
Investigate before you configure.
Use the CLI evidence to isolate the fault, make the smallest safe correction, then verify the network state changed.
Observe the symptom and link state.
Diagnose by comparing the protocol evidence.
Verify the expected device state and confirm the original symptom is resolved.
Console access: R4 (client) · RR1 (working) · RR2 (broken)
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Reveal the root cause when you're ready.
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Lab debrief
Turn the session into a repeatable troubleshooting pattern.
Use this reference after your attempt: first explain the symptom, then verify the evidence, then confirm the repair.
The problem
A client router in a route-reflector design stops receiving certain routes it should be reflected, even though the route reflectors themselves look healthy and their sessions are up.
What you'll practice
- Trace a reflected route from client to route reflector to client
- Read the ORIGINATOR_ID and CLUSTER_LIST a reflector adds
- See how cluster-IDs stop reflection loops between two reflectors
- Verify cluster-ID loop prevention and originator-ID handling
- Troubleshoot a client that isn't receiving reflected routes
The topology
Five iBGP routers in one AS: two route reflectors, each with its own cluster-ID, serving three clients, one of them attached to both reflectors. Enough scale to see the loop-prevention rules work for real.
Commands to run yourself
The real diagnostic commands for this lab, copy-paste ready. Run these in the same order to reproduce the investigation on your own session.
show ip bgp 192.168.50.0show ip bgp summaryshow ip bgp neighbors 10.0.0.4Topology diagram
Inside a real session
More genuine captures from this lab running on the platform, at full size so the console text stays readable.
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Fact-checked references
The commands and behaviour in this lab were checked against these primary references.
Frequently asked
Is this the same BGP topic as the Peering & Path Selection lab?
No. That lab covers eBGP/iBGP peering and best-path policy. This one is scoped specifically to route-reflector design and its cluster/originator-ID loop-prevention rules.
Does this cover CCNP ENARSI route reflector topics?
Yes. Route reflector design and iBGP scaling are explicit ENARSI (300-410) blueprint items.
Ready to run this lab yourself?
No setup, no image sourcing. Book a session or ask for a live demo.