N Is For Networking

Ethan and Holly continue their OSPF journey this week with OSPF Network Types. They discuss the two main OSPF network types used today: the broadcast and point to point networks. They also explain designated routers, backup designated routers, and when those are used and why. Lastly they discuss some soft skills – knowing your vendor ... Read more »

Our OSPF series continues with a look at OSPF neighbor formation and related timers. We talk about the five major packet types that carry information among OSPF routers, how OSPF routers become neighbors, how they negotiate link-state database exchanges, keep-alive messages, and how they negotiate designated and backup routers when multiple devices are on the ... Read more »

By popular request (and now that we have some other background topics covered) we start our series on the Open Shortest Path First (OSPF) routing protocol. We kick off the series with OSPF basics including Link State Advertisements, Link State Database, and other related essentials. We’ll explore additional OSPF topics over subsequent episodes. This week’s ... Read more »

If you need to route in your network, you can program static routes into all your routing-capable devices. And this can work. But at some point, you’re probably going to want to switch to a dynamic routing protocol. On today’s N Is For Networking, Ethan and Holly discuss the differences between static and dynamic routes, ... Read more »

What shape is your network? In other words, what is its topology? On today’s episode, we discover the different types of network topologies and designs used in the enterprise, data center, and service provider networks. We cover leaf/spine, hub and spoke, point to point, mesh, and others. We also talk about how topologies affect traffic ... Read more »

Let’s explore four goals of network design: stability, speed, scalability, and security. These goals are based on Ethan’s experience designing, building, and operating networks. Network architects and design experts might have other objectives, and that’s fine, but these four goals are the basis of today’s episode. Ethan and Holly discuss why these four goals are ... Read m...

We wanted to do an episode on SD-WAN, but realized we needed to set the stage for how wide-area networking developed. That’s why today’s episode is a history lesson of the Wide Area Network (WAN). We talk about how WANs emerged, public and private WANs, how WANs connect to LANs and data centers, the care ... Read more »

On today’s show, we’re going to dig deeper into tunnels and explore some of the quirks and features of tunnels. This week we’ll discuss maximum transmission units (MTUs), maximum segment size, IP fragmentation and more.  Today’s bonus material is more RFCs – RFC 4821 and RFC 8899. Episode Links: What Is a Tunnel? – N ... Read more »

Let’s dig into tunnels. While some network engineers may want to quibble, a tunnel is when you put one packet inside of another packet to carry it across a network (frames also come into the picture, so hold off on your follow-ups for now). On today’s N Is For Networking, Ethan and Holly explore this ... Read more »

The Dynamic Host Configuration Protocol (DHCP) assigns an IP address to a host that joins a network, along with other information necessary for the host to communicate. DHCP also has more to it, so this week’s episode is meant to be a solid introduction to this essential network protocol. We first discuss what it is ... Read more »

This week we continue with DNS. In our last episode we covered the basics; today we expand our scope to cover topics such as security for DNS, reverse DNS, and DNS record types. For dessert this week, a serving of Raspberry Pi and Happy Eyeballs. Episode Links: DNS: Turning Names into Numbers – N Is ... Read more »

The Domain Name System (DNS) keeps the Internet running. On today’s N Is For Networking podcast, we talk about how DNS transforms human-readable host names into IP addresses so that Internet traffic can be sent to the right place. We talk about root name servers, Top Level Domains (TLDs), and other elements of the DNS ... Read more »

Following last week’s introduction to network monitoring, we discuss the Simple Network Management Protocol (SNMP), one of the most implemented types of network monitoring. We discuss how it is organized, operations that SNMP can perform, and versions of SNMP. This week’s bonus conversation is a discussion on the future for SNMP. Episode Links: MIB tree ... Read more »

How do you know what is happening within your network, especially when something isn’t working? Network monitoring is the answer. On today’s show, we’ll start with the basics of network monitoring. We’ll cover what it is, how it’s used, and suggest some paid and open source network monitoring tools. This week’s bonus material is a ... Read more »

To cert or not to cert? That is the question Holly & Ethan discuss on today’s episode. Will a certification really land you a networking job? Are certs the guaranteed path to tech career success? We consider this, talking through the benefits, challenges and even risks of networking industry certification. And there’s some bonus material, ... Read more »

In today’s episode, we continue the discussion about routing and routing protocols by focusing on commonalities rather than differences among  protocols such as OSPF, RIP, EIGRP, or BGP. We explain how, in general, routing protocols discover each other, communicate, maintain relationships, and exchange routing information. Next, we explore the topics of selecting best paths in ... Read more »

Ready for more routing and routing protocols? Today we discuss the roles of the network operating system (NOS), routing protocols, the Routing Information Base (RIB), and the Forwarding Information Base (FIB). We also include the dynamics of routing protocols, the importance of hardware like TCAM for performance, and the concept of administrative distance or route ... Read more »

On today’s N Is For Networking, we explore the fundamentals of routing, focusing on layer 3 of the OSI model. We explain the concepts of routers, routing tables, and routing protocols, and discuss why it’s important to have a firm grasp of these concepts before you tackle advanced topics such as VXLAN and EVPN. Today’s ... Read more »

The line between switches and routers can get a little blurry. On today’s N Is For Networking, we try to clear things up. We start by defining what a router and switch are, and then provide some historical and technical context to better understand the differences. Then we discuss how modern switches have evolved to ... Read more »

We’re back with the third and last (for now) installment of our spanning tree series. Today’s episode includes an explanation of spanning tree versions, 802.1D, 802.1w, 802.1s, and their practical implications for network design. The discussion then turns to BPDU guard for preventing loops and ensuring rapid connectivity. Bonus material on why you should or ... Read more »

Welcome to part 2 of our spanning tree series. We start with a quick review and then discuss root bridges, root ports, designated ports, and forwarding and blocked ports.  We explain the impact of topology changes on spanning tree and network performance, and discuss how topology changes and convergence events are communicated. Last but not ... Read more »

Spanning tree is a topic so mysterious and complicated that common advice is just to disable it. In today’s episode, we start a mini-series on spanning tree, hoping to better explain what it is and what it does. We begin with basic spanning tree terminology and its role in preventing loops in an Ethernet network. ... Read more »

Why do we need network models such as OSI? Network architect and author Russ White joins Holly and Ethan to talk about how network models can help engineers ask intelligent questions and understand networking problems. And OSI isn’t your only option–Russ digs into the RINA model and how it compares to OSI (which we covered ... Read more »

In today’s episode, we address listener Kieren’s question about the differences between LAG, MLAG, MC-LAG, and stacking. We tackle the nuances of Link Aggregation (LAG) and the Link Aggregation Control Protocol (LACP), and explain their roles in redundancy and bandwidth efficiency. We also discuss the complexities and differences among vendors and overall benefits of Multi-Chassis ... Read more &#...

It’s history day on N Is For Networking! We learn about the development of IPv6 directly from Bob Hinden, one of the pioneers who made it happen. Bob discusses his journey from early work on ARPANET to his significant contributions to IPv6. We also cover the transition from IPv4, the challenges faced during IPv6’s creation, ... Read more »