Packets DownRange
Interconnection, peering, Data centers. How the Internet works. IXPs, transit, and other topics. Routing and Control Planes such as BGP and OSPF protocols. RPKI and IP resources are also covered.
5 minute read time.Justin Wilson j2sw.com When you configure a BGP session, one of the first questions is what routes you actually want to receive. If you have ever filled out a questionnaire with Hurricane Electric or another transit provider, they ask you what “kind” of routes you want. In this article, I plan to … Read more
If you’ve spent any time looking into fiber Internet, you’ve probably run across terms like GPON, XGS-PON, OLT, and ONT. These are all parts of what’s called a Passive Optical Network, or PON. Most residential fiber providers use PON because it lets them connect alot of homes without having to pull a separate fiber from … Read more
We are starting to hear about “Thin” and “Fat” rails in AI fabrics. These are just another way to say a connection from compute into the Fabric. The link either has sufficient capacity (Fat) or insufficient capacity (Thin). A thin rail provides the node with a single path into the fabric. That may be one … Read more
I originally posted this over on the FD-IX Bloghttps://blog.fd-ix.com/george-washington-the-delaware-and-direct-routes/ When George Washington crossed the Delaware River on Christmas night in 1776, the goal was simple. Reach the objective by the most effective path while avoiding unnecessary delays and giving the opposing force as little warning as possible. The crossing was risky, but it created a … Read more
A browser does not always need the whole file at once. Sometimes it only needs a slice of the file. That slice might be the next part of a video or a chunk of a large object sitting behind a CDN. When that happens, the client can request a byte range instead of requesting the … Read more
Justin Wilson announces his second children’s networking book, A Kid’s First Visit to an Internet Exchange. Follow Sam as he learns how networks meet, peer, and move Internet traffic.
A data center fabric connects servers, storage, and network devices using a leaf-spine architecture designed for high bandwidth and predictable latency. Learn how packets move through a fabric, why ECMP matters, and how modern data centers support virtualization, cloud, and AI workloads.
AI agents change network traffic patterns completely. Instead of humans opening browsers and apps, autonomous systems start talking directly to APIs, databases, sensors, and other agents. IPv6 removes the address limitations and NAT complexity that break large-scale AI communication.
Learn how ISP access networks work using fiber, Satellite, LTE, DOCSIS, and fixed wireless to deliver Internet to customers
Large VLAN domains depend on spanning tree. Every topology change triggers recalculation and temporary forwarding loss. EVPN-VXLAN replaces large Layer 2 domains with routed underlays and distributed MAC learning. Regional ISPs use this to connect data centers, IX edge infrastructure, and broadband aggregation networks without stretching spanning tree across sites VXLAN encapsulates Ethernet frames inside … Read more
A leaf-and-spine design is a data center network topology that removes the traditional three-tier hierarchy and treats every path equally. Traditional three-tier networks build layers like access, distribution, and core. This structure creates choke points when traffic has to move northbound through specific devices. A leaf and spine fabric flattens that design so every leaf … Read more
