Learning path

Data-centre fabrics

For: You build or operate leaf-spine networks

Layer 2 and VLANs, routing fundamentals and loopback design, IPv6-only cores, then EVPN and VXLAN to stretch layer 2 across a routed fabric.

1. Switching basics: layer 2, VLANs and IP addressingBeginner · 40 min

   How a switch learns MAC addresses and floods broadcasts, how IP subnets and default gateways decide where packets go, how VLANs split a switch into separate networks, and how trunks and a router connect them. Built on a real switch, three PCs and a VyOS router.

2. OSPF FundamentalsBeginner · 70 min

   The link-state IGP that runs inside most networks: neighbour adjacencies, LSA flooding, SPF, costs, DR/BDR, areas and LSA types, a hands-on FRR lab, and how OSPF underpins BGP.

3. BGP FundamentalsIntermediate · 75 min

   How the Border Gateway Protocol glues the internet together: autonomous systems, sessions, path attributes, best-path selection, iBGP scaling and a hands-on eBGP lab with real FRR configuration.

4. BGP on loopbacks vs interface addressesIntermediate · 45 min

   Why BGP sessions between loopbacks survive link failures and use parallel links, and what they need to work: an IGP or static routes, update-source, the eBGP connected check, and BFD. Every failure is reproduced on two real VyOS routers.

5. IPv6 on VyOS: setup and routingBeginner · 55 min

   Number a site from an ISP's /48 on VyOS: WAN and blackhole routes, SLAAC with Router Advertisements, handing a /56 to a downstream router statically and with DHCPv6 prefix delegation, and the forward firewall IPv6 needs because there's no NAT. Every output comes from a real two-router VyOS lab.

6. IPv4 over an IPv6-only core (RFC 8950)Intermediate · 40 min

   Carry IPv4 routes over IPv6 BGP sessions with IPv6 next hops, so core routers need no IPv4 addresses at all. Built on VyOS: the missing router ID, what breaks without the extended next hop capability, native IPv4 on the wire, and why traceroute shows 192.0.0.8.

7. EVPN and VXLAN: layer 2 over a routed fabricAdvanced · 45 min

   Stretch a layer-2 segment across a routed leaf-spine fabric: VXLAN for the data plane, BGP EVPN for the control plane. Built with FRR: the underlay, VNIs, type-2 and type-3 routes, route targets, and the VXLAN packets on the wire.