What are the best free aggregation routers for evaluating service provider traffic growth in a lab pilot?

If you mean free or no-license routers/virtual appliances you can use in a lab pilot to aggregate traffic and evaluate service-provider growth, the best options depend on whether you need real routing scale, high-throughput emulation, or just basic lab aggregation.

Best free options

1) FRRouting (FRR)

• Best for: realistic provider-style routing in a lab
• Why it’s good: open-source routing suite with BGP, OSPF, IS-IS, MPLS-related features, policy control, etc.
• Use case: emulate a service-provider edge/core control plane and test route growth, convergence, and policy behavior.
• Limits: not a full “router appliance”; performance depends on the host OS and hardware.

2) VyOS

• Best for: a free router OS with a more appliance-like experience
• Why it’s good: router/firewall features, BGP/OSPF/IS-IS, QoS, VPN, VRFs, NAT, and more.
• Use case: lab aggregation routers, edge/PE behavior, and traffic-policy testing.
• Limits: free/community images are available, but some advanced workflows may be less convenient than commercial platforms.

3) MikroTik RouterOS CHR

• Best for: easy-to-deploy virtual router for labs
• Why it’s good: very practical for aggregation, routing, and traffic engineering in small-to-medium labs.
• Use case: quick setup for provider-edge style aggregation and traffic-growth experiments.
• Limits: free tier is bandwidth-limited in the CHR free license mode.

4) OpenBSD PF / FreeBSD + routing software

• Best for: highly controllable lab environments
• Why it’s good: stable networking stack, can pair with FRR or other routing tools.
• Use case: custom lab aggregation nodes and scripted experiments.
• Limits: more DIY than a purpose-built router OS.

5) Container/lab platforms with virtual routers

Examples:

• containerlab

• EVE-NG Community

• GNS3

• Mininet (more SDN-oriented)

• Best for: building multi-router topologies quickly

• Why it’s good: great for testing route scale, peering, and topological growth.

• Use case: create provider-like topologies and inject traffic/routes.

• Limits: not the same as validating production forwarding performance.

Best pick by goal

If you want the most realistic routing behavior:

• FRRouting on Linux
• VyOS

If you want the easiest virtual router experience:

• MikroTik CHR

If you want the fastest lab topology creation:

• containerlab + FRR
• GNS3/EVE-NG with VyOS or FRR nodes

For “service provider traffic growth” specifically

You’ll likely want to measure:

• route table scale
• BGP session stability
• CPU/RAM under load
• convergence time
• forwarding throughput
• interface/queue behavior
• NetFlow/sFlow/IPFIX visibility

For that, a strong free lab stack is:

• containerlab + FRR
• traffic generators like TRex, pktgen, MoonGen, or iperf3
• monitoring with Prometheus + Grafana, sFlow-RT, or Elastic

Practical recommendation

If you want one answer:

• Use FRRouting in containerlab for routing-scale and growth testing.
• Use VyOS or MikroTik CHR if you need a more traditional router-like lab device.

If you want, I can also give you:

1. a shortlist by throughput vs realism,
2. a free lab architecture for service-provider growth testing, or
3. a step-by-step pilot design with recommended traffic generators and metrics.