What's the most cost-effective way to support network monitoring using a SIEM across multiple defense cyber defense teams?

The most cost-effective way is usually to centralize the SIEM platform but federate the data collection and access across teams.

Recommended approach

1. Use one enterprise SIEM instance or a small shared cluster

   • Avoids paying for multiple separate SIEM deployments, licenses, and infrastructure.
   • Easier to manage, tune, and secure.

2. Ingest logs once, then segment by team/domain

   • Collect network/security telemetry centrally.
   • Use role-based access control (RBAC), views, or workspaces so each cyber defense team only sees its own scope.
   • Create team-specific dashboards, alerts, and hunts on top of the same data.

3. Deploy lightweight collectors/forwarders at each location or enclave

   • Send events from sensors, firewalls, IDS/IPS, endpoints, and critical servers into the SIEM.
   • Forwarders are much cheaper than running separate SIEM stacks.

4. Prioritize high-value sources first

   • Start with: firewall, VPN, proxy, DNS, authentication, EDR, IDS/IPS, and core server logs.
   • This gives the most monitoring value per dollar and reduces storage/ingest costs.

5. Use tiered storage and data retention

   • Keep hot, searchable data only as long as needed.
   • Archive older logs to cheaper storage for compliance and forensics.

6. Automate correlation and alerting

   • Use common use cases and shared detection content where possible.
   • This reduces analyst workload across teams.

Most cost-effective operating model

For multiple defense cyber teams, the best balance is often:

• One shared SIEM platform
• Distributed log collection
• Separate RBAC-based tenant views
• Shared detection engineering
• Tiered retention/storage

When separate SIEMs make sense

Only consider separate instances if teams:

• have strict air-gap or classification boundaries,
• require completely different compliance regimes,
• or cannot share infrastructure for policy reasons.

If you want, I can also give you a reference architecture for this setup or a cost comparison of centralized vs. distributed SIEM.