Wrap-up and resources

Key Takeaways

• 1. The data centre network: spine-leaf, VXLAN and EVPN: A modern data centre is a simple, symmetrical routed network underneath (spine-leaf with ECMP) and a flexible virtual network on top (VXLAN) run by BGP EVPN. Every server is leaf-spine-leaf from any other, and you grow by adding a spine or a leaf without redesigning.
• 2. The wide area network: MPLS, SD-WAN and SASE: MPLS gives guaranteed quality at a high price, SD-WAN bundles cheaper links and picks the best one per app in real time, and SASE moves the firewall, the proxy and Zero Trust into the cloud. Most companies today run a mix: SD-WAN over internet with MPLS for critical sites.
• 3. Cloud networking at scale: hub and spoke and hybrid links: Plan addresses before the first network, because overlap cannot be fixed later. Join networks through a hub, not a web of direct peerings, inspect traffic in a central network, pick a dedicated link when you need steadiness and capacity, and write everything in Terraform.
• 4. Network design and availability: the capstone: Good design starts from requirements and is measured in numbers: the availability needed sets how much you duplicate, failure domains set where you separate, growth sets capacity. And every change has a method, a rollback plan and a time window.
• 5. The senior's road: roles, certificates and a one-year plan: Pick one role first (enterprise, data centre, cloud or automation), and let the certificate follow the experience, not the other way round. CCNP proves depth, CCIE proves mastery, and published projects and written investigations prove you actually do it.

Glossary