Blog Posts in 2021

December 2021

• That's It for 2021 (17 Dec 2021)
• Fast Failover: Marketing and Reality (16 Dec 2021)
• Highlights: Dynamic Negotiation of BGP Capabilities (15 Dec 2021)
• Checking Network Device Configurations in a GitOps CI Pipeline (14 Dec 2021)
• Running Network Automation Tools in a Container (13 Dec 2021)
• Worth Reading: Snowflake Network Devices (11 Dec 2021)
• Podcast: Ironing Out the BGP Ruffles (10 Dec 2021)
• Response: Hardware Differences between Routers and Switches (09 Dec 2021)
• What Are You Going to Test in Network Automation CI/CD Pipeline? (08 Dec 2021)
• Highlights: Multi-Threaded Routing Daemons (07 Dec 2021)
• Building a BGP Anycast Lab (06 Dec 2021)
• Worth Reading: Xen on AWS Nitro NICs (04 Dec 2021)
• Video: Machine Learning 101 (03 Dec 2021)
• Optimal BGP Path Selection with BGP Additional Paths (02 Dec 2021)
• Scalable Policy Routing (01 Dec 2021)

November 2021

• Dynamic Negotiation of BGP Capabilities (30 Nov 2021)
• Mikrotik RouterOS and VyOS Added to netsim-tools (29 Nov 2021)
• Git as a Source of Truth for Network Automation (28 Nov 2021)
• Worth Reading: Load Balancing on Network Devices (27 Nov 2021)
• Lesson Learned: Some Services Are Not Worth Delivering (26 Nov 2021)
• Circular Dependencies, VMware NSX-T Edition (25 Nov 2021)
• Anycast Fundamentals (24 Nov 2021)
• Multi-Threaded Routing Daemons (23 Nov 2021)
• netlab Custom Groups and Deployment Templates (22 Nov 2021)
• RFC 9098: Operational Implications of IPv6 Extension Headers (21 Nov 2021)
• Worth Reading: How to Get Useful Answers to Your Questions (20 Nov 2021)
• Video: Early Data-Link-Layer Addressing (19 Nov 2021)
• Hardware Differences between Routers and Switches (18 Nov 2021)
• Anycast Works Just Fine with MPLS/LDP (17 Nov 2021)
• Optimizing the Time-to-First-Byte (16 Nov 2021)
• Overlay Virtual Networking Examples (15 Nov 2021)
• Jerikan+Ansible: a Configuration Management System (14 Nov 2021)
• Interesting: What's Wrong with Bitcoin (13 Nov 2021)
• Non-Stop Routing (NSR) 101 (11 Nov 2021)
• Building a Separate Infrastructure for Guest Access (10 Nov 2021)
• Creating BGP Multipath Lab with netlab (09 Nov 2021)
• Feedback: Business Aspects of Networking (08 Nov 2021)
• Managing Hierarchical Device Configurations (07 Nov 2021)
• Soap Opera: SRv6 Is Insecure (06 Nov 2021)
• Video: How Can You Master Public Cloud Networking? (05 Nov 2021)
• Why Does Internet Keep Breaking? (04 Nov 2021)
• Even Simple Data Models Are a Huge Win (03 Nov 2021)
• Where Would You Need DNS Anycast? (02 Nov 2021)
• netsim-tools Release 1.0 (01 Nov 2021)

October 2021

• Worth Reading: Operators and the IETF (31 Oct 2021)
• Worth Reading: Programming Sucks (30 Oct 2021)
• Nonlinear Effects of Optimization-Induced Complexity (29 Oct 2021)
• Big Picture: BFD, Non-Stop Forwarding, and Graceful Restart (28 Oct 2021)
• EVPN/VXLAN Complexity (27 Oct 2021)
• Interactions Between BFD and Graceful Restart (26 Oct 2021)
• Feedback: How Networks Really Work (25 Oct 2021)
• Worth Reading: Making a Case for Automation Architecture (24 Oct 2021)
• Worth Reading: Network Validation Evolution at Hostinger (23 Oct 2021)
• Video: Introduction to AI/ML Hype (22 Oct 2021)
• Circular Dependencies Considered Harmful (21 Oct 2021)
• Do We Need Multiple Global IPv6 Addresses Per Interface (RFC 7934) (20 Oct 2021)
• Graceful Restart and BFD (19 Oct 2021)
• Start a Virtual Lab with a Single Command (18 Oct 2021)
• Worth Reading: The Software Industry IS STILL the Problem (17 Oct 2021)
• MUST READ: ARP Problems in EVPN (16 Oct 2021)
• Lessons Learned: Complexity Will Kill Your System (15 Oct 2021)
• BGP Optimal Route Reflection 101 (14 Oct 2021)
• Why Does DHCPv6 Matter? (13 Oct 2021)
• Graceful Restart and Routing Protocol Convergence (12 Oct 2021)
• New Content in AWS Networking Webinar (11 Oct 2021)
• OMG: Democratizing Network Automation (10 Oct 2021)
• Must Read: BGP Private AS Range (09 Oct 2021)
• Video: Theoretical View of Network Addressing (08 Oct 2021)
• Should You Build or Buy a Router? (07 Oct 2021)
• Worth Reading: Do We Need Segment Routing? (06 Oct 2021)
• Graceful Restart and Other Control Plane Protocols (05 Oct 2021)
• Feedback: Mastering Cloud Networking (04 Oct 2021)
• Video: Public Cloud Networking Is Different (01 Oct 2021)

September 2021

• Reusing Underlay Network for Infrastructure Services (30 Sep 2021)
• Watch Out: ISR Performance License (29 Sep 2021)
• Graceful Restart (GR) 101 (28 Sep 2021)
• State of IT Security in 2021 (27 Sep 2021)
• Worth Reading: Breaking Down Silos (24 Sep 2021)
• Building a Small Data Center Fabric with Four Switches (23 Sep 2021)
• IS-IS Flooding Details (22 Sep 2021)
• Another SD-WAN Security SNAFU: SQL Injections in Cisco SD-WAN Admin Interface (21 Sep 2021)
• netlab Network Topology Graphs (20 Sep 2021)
• Interesting Concept: Time Dilation (17 Sep 2021)
• LSA/LSP Flooding in OSPF and IS-IS (16 Sep 2021)
• New: ipSpace.net Design Clinic (15 Sep 2021)
• Stateful Switchover (SSO) 101 (14 Sep 2021)
• Configuring NSX-T Firewall with a CI/CD Pipeline (13 Sep 2021)
• Worth Reading: Ops Questions in Software Engineering Interviews (11 Sep 2021)
• Lessons Learned: Fundamentals Haven't Changed (10 Sep 2021)
• netlab Overview (09 Sep 2021)
• Open-Source DMVPN Alternatives (08 Sep 2021)
• Non-Stop Forwarding (NSF) 101 (07 Sep 2021)
• Comparing Forwarding Performance of Data Center Switches (06 Sep 2021)
• Video: Introduction to Network Addressing (03 Sep 2021)
• Automating NSX-T Firewall Configuration (02 Sep 2021)
• netlab Python Package and Unified CLI (01 Sep 2021)

August 2021

• Worth Reading: A Historical Perspective On The Usage Of IP Version 9 (30 Aug 2021)
• Worth Reading: Simplifying Networks (23 Aug 2021)
• MUST Read: Operational Security Considerations for IPv6 Networks (RFC 9099) (16 Aug 2021)
• netsim-tools Release 0.8.1: Cumulus VX and Nokia SR Linux Containers (08 Aug 2021)

July 2021

• OpenFlow Realities, 2021 Edition (29 Jul 2021)
• Quantum Computing and OpenFlow (22 Jul 2021)
• Designing Networks: From Tricycles to Aircraft Carriers (12 Jul 2021)

June 2021

• Thank You for Everything Irena, We'll Miss You Badly (30 Jun 2021)
• Webinars in the First Half of 2021 (28 Jun 2021)
• Worth Reading: Blog About What You've Struggled With (27 Jun 2021)
• Worth Reading: How to Miss a Deadline (26 Jun 2021)
• Video: Typical Large-Scale Bridging Use Cases (25 Jun 2021)
• Stretched VLANs: What Problem Are You Trying to Solve? (24 Jun 2021)
• Why Do We Need BGP-LS? (23 Jun 2021)
• Unexpected Interactions Between OSPF and BGP (22 Jun 2021)
• Comparing EVPN with Flood-and-Learn Fabrics (21 Jun 2021)
• Worth Reading: Machine Learning Deserves Better Than This (20 Jun 2021)
• Worth Reading: Is Your Consultant a Parasite? (19 Jun 2021)
• Video: Comparing Routing and Bridging (18 Jun 2021)
• Questions about BGP in the Data Center (with a Whiff of SRv6) (17 Jun 2021)
• Deploying Plug-and-Pray Software in Large-Scale Networks (16 Jun 2021)
• OSPF Inter-Process Route Selection (15 Jun 2021)
• ipSpace.net Subscription for System Administrators (14 Jun 2021)
• Intricate AWS IPv6 Direct Connect Challenges (13 Jun 2021)
• Worth Reading: The Lost Designer (12 Jun 2021)
• Lessons Learned: Technology Still Matters (11 Jun 2021)
• Unnumbered Ethernet Interfaces, DHCP Edition (10 Jun 2021)
• Real-Life Network-as-a-Graph Examples (09 Jun 2021)
• Unequal-Cost Multipath with BGP DMZ Link Bandwidth (08 Jun 2021)
• Feedback: Azure Networking (07 Jun 2021)
• Worth Reading: The Neuroscience of Busyness (06 Jun 2021)
• Worth Reading: Switching to IP fabrics (05 Jun 2021)
• Video: Cisco SD-WAN Policy Design (04 Jun 2021)
• Routing Protocols: Use the Best Tool for the Job (03 Jun 2021)
• Unnumbered Ethernet Interfaces (02 Jun 2021)
• Single-Metric Unequal-Cost Multipathing Is Hard (01 Jun 2021)

May 2021

• netsim-tools release 0.7: Cumulus VX, EIGRP, and BGP IPv6 AF (31 May 2021)
• Worth Reading: Azure Datacenter Switch Failures (30 May 2021)
• Worth Reading: Running BGP in Large-Scale Data Centers (29 May 2021)
• Video: Kubernetes Principles (28 May 2021)
• Local TCP Anycast Is Really Hard (27 May 2021)
• Packet Forwarding and Routing over Unnumbered Interfaces (26 May 2021)
• Mythbusting: NFV Data Center Fabric Buffering Requirements (25 May 2021)
• Feedback: Kubernetes Networking Deep Dive (24 May 2021)
• Worth Watching: Rethinking BGP in the Data Center (23 May 2021)
• Worth Exploring: Working with Linux VRFs (22 May 2021)
• Video: We Still Need Networking in Public Clouds (21 May 2021)
• Automation: Dealing with Vendor-Specific Configuration Keywords (20 May 2021)
• Back to Basics: Unnumbered IPv4 Interfaces (19 May 2021)
• Packet Bursts in Data Center Fabrics (18 May 2021)
• netsim-tools release 0.6.2 (17 May 2021)
• Worth Reading: Rethinking Internet Backbone Architectures (16 May 2021)
• Video: Cisco SD-WAN Site Design (14 May 2021)
• Does Small Packet Forwarding Performance Matter in Data Center Switches? (13 May 2021)
• Back to Basics: The History of IP Interface Addresses (12 May 2021)
• BGP-Free MPLS Core with Segment Routing (11 May 2021)
• Response: There's No Recipe for Success (10 May 2021)
• Worth Reading: When Stretching Layer Two, Separate Your Fate (09 May 2021)
• Worth Reading: My Secret Startup Past (08 May 2021)
• Video: IP Routing Fundamentals (07 May 2021)
• Real-Life: How to Start Your Automation Journey (06 May 2021)
• Back to Basics: Do We Need Interface Addresses? (05 May 2021)
• Segment Routing Segment IDs and MPLS Labels (04 May 2021)
• Feedback: Microsoft Azure Networking (03 May 2021)
• RFC 7868: The Definitive EIGRP Guide (01 May 2021)

April 2021

• Blogging Rule#1: Own Your Content (29 Apr 2021)
• netsim-tools Release 0.6: BGP, IS-IS, SR-MPLS, FRR (28 Apr 2021)
• MUST READ: Deploy AWS Security Rules in a GitOps World with Terraform, GitLab CI, Slack, and Python (27 Apr 2021)
• Everything Is a Graph (26 Apr 2021)
• Worth Reading: Understand Your Single Points of Failure (25 Apr 2021)
• Worth Reading: The Insider's Guide To Evangelizing Good Design (24 Apr 2021)
• Interview: What New Technologies Should You Aim to Master? (23 Apr 2021)
• Microsoft Azure: Remember Exchange Server? (22 Apr 2021)
• Response: Is Switching Latency Relevant? (21 Apr 2021)
• Using Unequal-Cost Multipath to Cope with Leaf-and-Spine Fabric Failures (20 Apr 2021)
• Starting Network Automation for Non-Programmers (19 Apr 2021)
• Worth Reading: Get Better at Programming by Learning How Things Work (18 Apr 2021)
• MUST READ: Machine Learning is a Marvelously Executed Scam (17 Apr 2021)
• Video: Transparent Bridging Fundamentals (16 Apr 2021)
• Fundamentals: Is Switching Latency Relevant? (15 Apr 2021)
• Netsim-tools Release 0.5 Work with Containerlab (14 Apr 2021)
• Must Read: Automate Nexus-OS Fabric Deployment (13 Apr 2021)
• Start Automating Public Cloud Deployments with Infrastructure-as-Code (12 Apr 2021)
• Worth Reading: Fail-Fast is Failing... Fast (11 Apr 2021)
• Worth Reading: Data Manipulation in Jinja2 (10 Apr 2021)
• Bringing New Engineers into Networking on Software Gone Wild (09 Apr 2021)
• Claim: You Don't Have to Be a Networking Expert to Do Kubernetes Network Security (08 Apr 2021)
• Reader Question: What Networking Blogs Would You Recommend? (07 Apr 2021)
• Free Exercise: Build Network Automation Lab (06 Apr 2021)
• Building Unnumbered Ethernet Lab with netlab (05 Apr 2021)
• Video: Why Do We Need Kubernetes? (02 Apr 2021)
• Planning the Extended Coffee Break: Three Months Later (01 Apr 2021)

March 2021

• Intermittent Terraform Authentication Failure Using AWS Provider in a Vagrant VM (31 Mar 2021)
• Dealing with Cloud Challenges (30 Mar 2021)
• netsim-tools: Unnumbered Interfaces, Configuration Modules, OSPF (29 Mar 2021)
• Worth Reading: Learning without Burnout (28 Mar 2021)
• Worth Reading: Network Automation ChatBot with Discord (27 Mar 2021)
• Interview: Will AI Replace the Networking Engineers? (26 Mar 2021)
• Relative Speed of Public Cloud Orchestration Systems (25 Mar 2021)
• Hands-On: Azure Route Server (24 Mar 2021)
• Unequal-Cost Multipath in Link State Protocols (23 Mar 2021)
• There's No Recipe for Success (22 Mar 2021)
• Worth Reading: Splitting the Ping (21 Mar 2021)
• Interview: Is Networking Dead? (19 Mar 2021)
• Public Cloud Behind-the-Scenes Magic (18 Mar 2021)
• Repost: Using MP-TCP to Utilize Unequal Links (17 Mar 2021)
• Using YAML Instead of Excel in Network Automation Solutions (16 Mar 2021)
• Azure Route Server: Behind the Scenes (15 Mar 2021)
• Worth Reading: Modules, Monoliths, and Microservices (14 Mar 2021)
• Video: Cisco SD-WAN Routing Design (12 Mar 2021)
• Topology- and Congestion-Driven Load Balancing (11 Mar 2021)
• Azure Route Server: The Challenge (10 Mar 2021)
• Interesting Tool: Schema Enforcer (09 Mar 2021)
• Implementing Layer-2 Networks in a Public Cloud (08 Mar 2021)
• MUST READ: Systems Design Explains the World (07 Mar 2021)
• Worth Reading: Career Advice for Young Engineers (06 Mar 2021)
• Video: Path Discovery in Transparent Bridging and Routing (05 Mar 2021)
• New Ansible Data Validation Module(s) (04 Mar 2021)
• Chasing Anycast IP Addresses (03 Mar 2021)
• Impact of Azure Subnets on High Availability Designs (02 Mar 2021)
• Rant: Cisco ACI Complexity (01 Mar 2021)

February 2021

• Video: High-Level Technology Guidelines (26 Feb 2021)
• Does Unequal-Cost Multipathing Make Sense? (25 Feb 2021)
• Routing in Stretched VLAN Designs (24 Feb 2021)
• Virtual Networks and Subnets in AWS, Azure, and GCP (23 Feb 2021)
• MUST READ: Designing a Simple Disaster Recovery Solution (22 Feb 2021)
• Worth Reading: How To Put Faith in $someTechnique (20 Feb 2021)
• Podcast: State of Networking (Early 2021) (19 Feb 2021)
• Data Model Transformations in Network Automation Solutions (18 Feb 2021)
• Link-State Routing Protocols Are Eventually Consistent (17 Feb 2021)
• Availability Zones and Regions in AWS, Azure and GCP (16 Feb 2021)
• Rant: Don't Ever Compare Enterprise IT Shenanigans with Apollo 13 (15 Feb 2021)
• Worth Reading: Internet of Trash (14 Feb 2021)
• Worth Reading: Advice(s) for Engineering Managers (13 Feb 2021)
• Video: Cisco SD-WAN Policies Review (12 Feb 2021)
• Repost: On the Importance of Line-Rate Switching of Small Packets (11 Feb 2021)
• State Consistency in Distributed SDN Controller Clusters (10 Feb 2021)
• Demonstrate Small Automation Wins (09 Feb 2021)
• OMG, It's Graphs Everywhere (08 Feb 2021)
• Worth Reading: Visualizing BGP-LS Tables (07 Feb 2021)
• Worth Reading: Finding Bugs in C and C++ Compilers (06 Feb 2021)
• Video: Finding Paths Across the Network (05 Feb 2021)
• MUST READ: Fast and Simple Disaster Recovery Solution (04 Feb 2021)
• Impact of Centralized Control Plane Partitioning (03 Feb 2021)
• Rant: Broadcom and Network Operating System Vendors (02 Feb 2021)
• Thank You for All the Great Work Miha (01 Feb 2021)

January 2021

• Worth Reading: Understanding Table Sizes on the Arista 7050QX-32 (31 Jan 2021)
• Worth Reading: AAA Deep Dive on Cisco Devices (30 Jan 2021)
• FreeRTR Deep Dive on Software Gone Wild (29 Jan 2021)
• Build Virtual Lab Topology: VirtualBox Support (28 Jan 2021)
• Deploying Advanced AWS Networking Features (27 Jan 2021)
• Fixing XML-to-JSON Conversion Challenges (26 Jan 2021)
• New Webinar: Network Automation Concepts (25 Jan 2021)
• Worth Reading: Cloud Complexity Lies (23 Jan 2021)
• Podcast: IPv6 in the Cloud (22 Jan 2021)
• How Important is BGP RPKI? (21 Jan 2021)
• XML-to-JSON Information Loss, Cisco Nexus OS Edition (20 Jan 2021)
• Repost: VMware Fault Tolerance Woes (19 Jan 2021)
• Build Virtual Lab Topology: Dual Stack Addressing, ArcOS and Junos Support (18 Jan 2021)
• Video: Multi-Layer Switching and Tunneling (15 Jan 2021)
• Beware XML-to-JSON Information Loss (Junos with Ansible) (14 Jan 2021)
• Imperative and Declarative API: Another Pile of Marketing Deja-Moo (13 Jan 2021)
• Automation Win: Chatops-Based Security (12 Jan 2021)
• Webinars in 2021 (11 Jan 2021)
• Worth Reading: AI/ML/Space Predictions Scorecard, 2021 Edition (09 Jan 2021)
• Video: Cisco SD-WAN Policies and Centralized Magic (08 Jan 2021)
• Considerations for Host-based Firewalls (Part 2) (07 Jan 2021)
• IBGP, IGP Metrics, and Administrative Distances (06 Jan 2021)
• Planning the Next Extended Coffee Break (05 Jan 2021)
• Reviving Old Content, Part 3 (04 Jan 2021)