NetworkEngineering

A MAC address leaves a Cisco datacenter and reappears behind a Juniper leaf in another one. Watch RFC 7432 do its job across the multisite DCI: the counter climbing 0, 1, 2, the losing leaf yielding, and the exact BGP packets that carried each move, captured on the interconnect.

Type-2 gets all the attention, but a datacenter fabric runs on five core EVPN route types and quietly depends on every one. Here is what each actually carries, decoded from a live multihomed fabric, including the two types MLAG labs never get to show you.

A traceroute between two datacenters comes back as six lines. Each one is a precise statement about what a multisite EVPN-VXLAN fabric does to a packet: the anycast gateway, the VXLAN wrap and unwrap, numbered versus unnumbered routers, the crossing between sites. All six, decoded on the boxes.

vJunos on containerlab is routine on Intel. On an AMD EPYC host the stock image refuses to start its nested VM, and the first test topology most people write hides a second failure that looks like AMD and is not. What breaks, what current vrnetlab already fixes, all reproduced on an EPYC 9575F.

Put the vJunos 26.2 images on an AMD EPYC box running EVE-NG: the switch and router power themselves off, patch that and they hang at mount root, and Evolved on the default AMD template never starts QEMU. Four small edits in two places, each reproduced on the EPYC, every command ready to copy.