NEXT-HOP.DEV

  1. 1969ARPANET
  2. 1983TCP/IP
  3. 1986NSFNET
  4. 1995Commercial
  5. 2026next-hop.dev
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sitenext-hop.dev
typenetwork engineering research notebook
scoperouting, data center, service provider, cloud, security, automation
methodproblem → hypothesis → lab → evidence → write-up
evidencecaptured CLI and packet captures, rebuildable labs
sourcesRFCs, vendor documentation, vendor study tracks
platformsnetlab, containerlab, EVE-NG, GNS3, bare metal
repogithub.com/next-hop-pando/next-hop-labs

next-hop.dev is a network engineering research notebook, kept in public. Each post starts from a real problem: a design question, a protocol behavior, a failure mode or a migration. It gets worked through in a lab until the evidence answers it.

The material comes from three places: technologies and designs from production networks, newer designs worth taking apart before trusting them, and vendor study tracks (Juniper routing and switching, Cisco's enterprise track, network design references) read closely and tested hands-on.

Posts are written for working engineers. Anyone with a networking background can follow them, and they go deep enough to keep as a reference: how a protocol actually behaves, where a design breaks, and what the trade-offs cost.

What the Site Covers

Green links have posts today. Grey areas are on the roadmap.

next-hop.dev
Routing and ProtocolsBGP, OSPF, IS-IS and MPLS: path selection, policy, convergence and failure behavior.● up Data CenterSpine-leaf fabrics, VXLAN and EVPN, multihoming and fabric design trade-offs.● up
Enterprise Routing and SwitchingCampus design, Layer 2 behavior, segmentation, enterprise WAN and SD-WAN.○ planned
Service ProviderMPLS L3VPN and L2VPN, segment routing, traffic engineering and Internet edge design.○ planned
Cloud NetworkingVPC design, transit architectures, hybrid connectivity and BGP to the cloud.○ planned
Security and FirewallingFirewall policy and NAT, segmentation, network access control and routing security.● up Automation and CodePython, Ansible, device APIs and config-as-code, plus new tools as they earn their place.● up
Linux and VirtualizationThe Linux networking stack, containers and the virtual platforms labs and networks run on.○ planned
Network DesignFailure domains, scale, redundancy and migrations: why one design wins over another.○ planned
All PostsThe full archive, newest first.→ browse all

How the Work Is Done

The same standard applies to every post.

Tested before publishedEvery behavior described in a post was observed in a lab, on a named platform and software version.
Prediction, then evidenceEach test states the expected result first. Expected and observed stay separate, including when the prediction was wrong.
Real outputCLI output and packet captures come from saved lab files, never retyped. Trimmed output is marked as trimmed.
Rebuildable labsTopologies and configs live in files in the public repo, so any lab can be rebuilt and checked.
Primary sourcesRFCs and vendor documentation back the theory. Practitioner opinions are cited as opinions.
Corrections welcomeSpot an error? Open an issue on the repo and it gets fixed in the post.

The Lab Bench

Most labs run on netlab and containerlab. EVE-NG, GNS3 and bare-metal servers come in when a lab needs them. Each post names the platform and image versions it used.

netlabcontainerlabEVE-NGGNS3 bare metalPythonAnsibleLinux
Browse the lab sources
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Author information for next-hop.dev
-------------------------------------
NameJake Pando
Handlenext-hop-pando
RoleNetwork engineer
Works onenterprise, campus and data center networks
PlatformsJuniper, Arista, Cisco, Palo Alto
InterestsInternet architecture, data center fabrics, network security, design
GitHubgithub.com/next-hop-pando
Statusup, posting