# network engineering Published articles for network engineering. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## Using Cisco Prefix Lists Inside Route Maps for BGP Filtering DevFeed: [Using Cisco Prefix Lists Inside Route Maps for BGP Filtering]() Original publisher: [Read original article]() Author: j2sw Published: 2026-08-11T14:48:44Z Content type: tutorial Language: en Sources: [Justin Wilson (j2sw)]() Topics: [BGP](), [Cisco](), [Network]() Tags: [bgp](), [bgp-filtering](), [cisco](), [internet-architecture](), [network-engineering](), [network-engineering-resources](), [prefix-lists](), [route-maps](), [routing-policy]() ### AI overview This tutorial explains how Cisco prefix lists and route maps work together for BGP filtering. Prefix lists define which routes match, while route maps apply actions such as permitting, denying, or modifying route attributes. It also describes route-map sequence order and implicit deny behavior. ### Source excerpt Prefix lists define which BGP routes match a policy. Route maps use those matches to permit routes, deny them, or change attributes such as local preference. The post Using Cisco Prefix Lists Inside Route Maps for BGP Filtering appeared first on Justin Wilson (j2sw). ## Why Your Traffic Didn't go the way you expected DevFeed: [Why Your Traffic Didn't go the way you expected]() Original publisher: [Read original article]() Author: j2sw Published: 2026-07-28T15:16:02Z Content type: tutorial Language: en Sources: [Justin Wilson (j2sw)]() Topics: [BGP](), [Routing (disambiguation)](), [networking]() Tags: [bgp](), [fd-ix](), [network-engineering](), [network-operations](), [networking](), [peering](), [routing](), [routing-table](), [transit]() ### AI overview This troubleshooting article explains why traffic may not use an expected peering path even when a BGP session is established. It focuses on routing-table selection, Local Preference, BGP policy, and the possibility that return traffic follows a different path. ### Source excerpt 3 Mintue read timeJustin Wilson PacketsDownRange A common problem I run into when diagnosing route issues is traffic not going across the path it's supposed to. An established BGP session only means the routers successfully exchanged routes. It says nothing about which route your router actually installed in the forwarding table. Let's get into some ... Read more The post Why Your Traffic Didn't go the way you expected appeared first on Justin Wilson (j2sw). ## Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes DevFeed: [Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes]() Original publisher: [Read original article]() Author: j2sw Published: 2026-07-24T16:28:00Z Content type: article Language: en Sources: [Justin Wilson (j2sw)]() Topics: [BGP](), [networking](), [Routing (disambiguation)](), [Internet](), [gateway](), [Networks]() Tags: [bgp](), [cpu](), [flexibility](), [internet-architecture](), [isp](), [memory](), [network-engineering](), [network-operations](), [route](), [router](), [routing](), [routing-policy](), [routing-table](), [traffic-engineering](), [visibility]() ### AI overview This article explains BGP route choices, comparing default routes, full routes, partial routes, and customer routes. It describes the tradeoffs between small routing tables, Internet visibility, traffic engineering control, and router resource requirements. ### Source excerpt 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 The post Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes appeared first on Justin Wilson (j2sw). ## Useful Python Libraries Every Network Engineer Should Know DevFeed: [Useful Python Libraries Every Network Engineer Should Know]() Original publisher: [Read original article]() Author: j2sw Published: 2026-07-21T12:35:00Z Content type: tutorial Language: en Sources: [Justin Wilson (j2sw)]() Topics: [Python](), [Library](), [networking](), [Code]() Tags: [apis](), [automation](), [bgp](), [cisco](), [code](), [devops](), [firewalls](), [library](), [netops](), [network](), [network-engineering](), [network-operations](), [python](), [python-libraries]() ### AI overview This article introduces Python libraries for network engineering, explaining how they support device connections, API interactions, automation, configuration backups, audits, and reports. It discusses Netmiko, NAPALM, Nornir, Paramiko, and Requests. ### Source excerpt A Python script usually spends very little time doing actual Python work. Most of the actual work comes from libraries that know how to connect to network devices and do the work. They interact with APIs. Once you understand what each library does, you can spend less time writing code and more time solving network ... Read more The post Useful Python Libraries Every Network Engineer Should Know appeared first on Justin Wilson (j2sw).