This article explains why ping and TCP may travel different network paths, covering router behavior, routing tables, OSPF, Dijkstra's algorithm, ECMP, five‑tuple hashing, packet reordering, and practical troubleshooting techniques such as traceroute and nc.
An in‑depth post‑mortem of a flawed network cut‑over project between two merged units, detailing the original design, traffic analysis, OSPF and PBR configurations, step‑by‑step migration procedures, encountered issues, root‑cause investigations, and key takeaways for future network operations.
The article examines the history, current relevance, vendor support, and practical testing of IPv4 Class E address space, evaluating its potential as a local unicast pool amid IPv4 exhaustion and the challenges of deploying it with routing protocols like OSPF and BGP.
This article explores the history, technical feasibility, vendor support, and real‑world testing of the unused IPv4 Class E address block (240.0.0.0/4), concluding that while it can serve large private networks, widespread adoption is impractical and IPv6 remains the preferred solution.
This article provides step‑by‑step OSPF lab exercises for Huawei, Cisco, and Juniper devices, covering basic OSPF concepts, configuration guidelines, verification commands, and troubleshooting tips, enabling readers to build and test a multi‑vendor OSPF network topology.
This article examines three real‑world routing loop incidents caused by static‑route misconfiguration, missing passive‑interface settings in OSPF, and improper bidirectional redistribution, and provides detailed analysis and practical recommendations to prevent such loops in enterprise network operations.
Although ping and TCP both rely on IP, they can follow different network routes due to routing protocols, equal‑cost multi‑path (ECMP) decisions, and five‑tuple hashing, which explains why a host may be reachable by ping but occasionally fail to establish a TCP connection.
This comprehensive guide explains the purpose, types, metrics, and convergence behavior of major routing protocols—including static, dynamic, distance‑vector, and link‑state protocols such as OSPF, EIGRP, RIP, IS‑IS, and BGP—while detailing their selection algorithms, administrative distances, and key configuration concepts.
This comprehensive guide explains when to employ multiple routing protocols, compares distance‑vector and link‑state routing, details access‑list types and creation commands, outlines route redistribution steps and commands, clarifies administrative distance, BGP fundamentals, metric concepts, and provides hardware compatibility notes for Cisco routers and switches.
This article explains how OSPF avoids routing loops by using various LSA types—Type‑1, Type‑2, Type‑3, Type‑4, and Type‑5—and the role of ABRs, backbone requirements, and SPF calculations in maintaining a loop‑free network topology.
This article details a company's migration from commercial load balancers to an open‑source Nginx‑based Layer‑4 solution, covering project background, technical selection, architecture design, network and Nginx configurations, operational scripts, health‑check automation, performance testing, and data analysis using Elasticsearch and Grafana.
