BGP Unnumbered Overview

The Border Gateway Protocol (BGP) is an IP reachability protocol that you can use to exchange IP prefixes. Traditionally, one of the nuisances of configuring BGP is that if you want to exchange IPv4 prefixes you have to configure an IPv4 address for each BGP peer. In a large network, this can consume a lot of your address space, requiring a separate IP address for each peer-facing interface.

BGP Over IPv4 Interfaces

To understand where BGP unnumbered fits in, it helps to understand how BGP has historically worked over IPv4. Peers connect via IPv4 over TCP port 179. Once they’ve established a session, they exchange prefixes. When a BGP peer advertises an IPv4 prefix, it must include an IPv4 next hop address, which is usually the address of the advertising router. This requires, of course, that each BGP peer has an IPv4 address.

As a simple example, using the Cumulus Reference Topology, let’s configure BGP peerings as follows:

Between spine01 (AS 65020, 10.1.0.0/31) and leaf01 (AS 65011, 10.1.0.1/31)

Between spine01 (10.1.0.4/31) and leaf02 (AS 65012, 10.1.0.5/31)

Leaf01 will advertise the prefix 192.0.2.1/32 and leaf02 will Continue reading

Can your network handle digital transformation?

Digital transformation means different things to different organizations. Perhaps it means shifting workloads to the cloud, digging deeper into data analytics, giving your employees more options for mobility or automating more processes. But one thing’s for sure: no matter what your digital transformation strategy looks like, your network is going to be either the hero or a hindrance to your digital transformation efforts.

According to Gartner, “the top networking challenge… is improving agility.” Not a big surprise there. But what is surprising is Gartner’s advice to “shift investments away from premium networking products toward [your] existing network personnel.” That’s right: the answer to improving your network’s speed and agility is not by buying expensive, proprietary monster switches and premium automation solutions. Rather, it’s by letting the people who best know your network decide the best way to make your network more agile.

Agile networks require a deep understanding of your organizational objectives. A “one size fits all” approach to networking just doesn’t work anymore. In order to prepare your network for digital transformation, it has to be both customized to fit your organization’s needs and be flexible enough to adapt when those needs change. Agility requires responsive, Continue reading

Web-scale: a healthy choice for healthcare networks

Major cloud providers are able to achieve impressive uptime by distributing the load across a large number of commodity servers. There’s no single master server that can fail and bring down the entire infrastructure. It’s not surprising then that so many healthcare networks are already relying on major cloud providers to run electronic medical records (EMR) and imaging applications and store patient data. So doesn’t it make sense to adopt the same approach for the network?

Healthcare networks face a unique challenge that many other networks don’t: how do you grow your network quickly and reliably while remaining compliant? As patient data grows, this tension between growth and compliance is increasing. Healthcare networks are feeling the pressure to move data faster, and this often requires adding more connections and switches, which entails routing and other configuration changes. These continual and rapid changes come at the cost of long, sometimes unplanned, outages. Planned outages are to be expected, but unexpected outages are a nightmare. Consequently, many healthcare networks have understandably opted for slower network growth to maintain a stable, reliable network.

But thanks to the advent of web-scale networking, the tension between growth and compliance is quickly becoming a thing Continue reading

How to operationalize Cumulus Linux

Thanks to the limitations of traditional networks, network operators are accustomed to doing everything manually and slowly. But they want to perform configuration, troubleshooting and upgrades faster and with fewer mistakes. They’re ready and willing to learn a new approach, but they want to know what their options are. More importantly, they want to do it right. The good news is, regardless of your organization’s specific goals, you can operationalize Cumulus Linux to meet those objectives faster and more consistently. This post will help you understand your options for developing agile, speed-of-business workflows for:

• Configuration management
• Backup and recovery
• Troubleshooting

And if you’re looking for a deeper, more technical dive into how to implement these network operations, download this white paper.

Configuration management

Automation

The biggest disadvantage of manual configurations is that they simply don’t scale. Implementing BGP across dozens of switches is a copy-and-paste endeavor that’s time-consuming and prone to error. Not only that, checking that the configuration took effect and works as expected requires hop-by-hop verification in addition to testing route propagation and IP connectivity. However, In a small network, there’s no shame in at least starting out doing everything by hand.

Cumulus Linux lets you use a Continue reading

How can web-scale networking improve your campus networks?

When you think of your ideal campus network, the term “web-scale” may not immediately come to mind. After all, the term web-scale is something you’re more likely to associate with the cloud than with your network. But you might be surprised to learn that your ideal campus network fits the definition of a web-scale network to a T.

Fundamentally, a web-scale network functions as a single unit that can grow and change on demand, without requiring hands-on reconfiguration of multiple switches or mass hardware replacement. And because it functions as a single unit, a web-scale network can also give you full visibility into the health of your network, end-to-end.

The primary way web-scale networks achieve this flexibility and visibility is by decoupling or disaggregating the hardware and the network operating system (NOS) that runs on the hardware. Since the advent of specialized hardware networking devices, the operating system and hardware have been tightly coupled together. Proprietary NOSes often have platform-independent code that runs only on specialized hardware. Because of that, upgrading to a new software version often means buying new hardware. In some cases, that may be as simple as buying additional RAM to support the new version. In more Continue reading

Top 5 tips for transitioning to 100G networking

No doubt about it: the prospect of adding another zero to the end of your top network speeds is exciting. And the reward of the immediately noticeable performance improvement never gets old. Speed makes a noticeable, and not just measurable, difference. And with the massive increase in the amount of data servers need to process, 100G is soon going to be a necessity for many organizations.

But increasing network speed is about more than pushing more bits across a wire. Faster networks enable you to squeeze more out of your physical rack space. You need fewer servers, fewer network connections, and – dare I say it – fewer switches. It’s true. A faster network lets you pack more computing into the same space.

Whether you plan to do a forklift upgrade to 100G or intend to replace one switch at a time, there are some key things you need to know to avoid getting locked into one switch vendor or losing backward compatibility with your existing equipment. In this post, I’m going to give you my top 5 tips for making transitioning to 100G networking a smooth one.

Tip No. 1: Decide where 25G/100G makes sense

First, a little background. Continue reading

Automating Cumulus Linux with Ansible

Automating your network can seem like a daunting task. But the truth is that automating Cumulus Linux with Ansible can be easier than many of the things you’re probably already automating.

In this post, I’ll show you how to get started on your network automation journey using a simple, four-step process:

1. Pick one small network task to automate
2. Configure it manually on a small scale
3. Mimic the manual configuration in Ansible
4. Expand the automation to additional network devices

To illustrate, I’ll be using the following simple, bare-bones topology based on the Cumulus Reference topology. You can follow along by spinning up your own virtual data center for free using Cumulus in the Cloud.

Pick one network task to automate

The first step is to pick one thing to automate. Just one! The only caveat is that it needs to be something you understand and are comfortable with. Trying to automate a feature you’ve never used is sure to scare you away from automation forever, unless of course you have someone guiding you through the process.

Preferably, pick something that’s quick and simple when done manually. Configuring the OSPF routing protocol between two switches falls into this category. When done manually, Continue reading

5 Network automation tips and tricks for NetOps

Despite what some people say, automation is not for the lazy. This opinion probably comes from the fact that the whole point of automation is to reduce repetitive tasks and make your life easier. Indeed automation can do just that, as well as giving you back hours each week for other tasks.

But getting your automation off the ground to begin with can be a challenge. It’s not as if you just decide, “Hey, we’re going to automate our network now!” and then you follow a foolproof, well-defined process to implement network automation across the board. You have to make many decisions that require long discussions, and necessitate ambitious and careful thinking about how you’re going to automate.

Just as with anything else in the IT world, there are no one-size-fits-all solutions, and no “best practices” that apply to every situation. But there are some common principles and crucial decision points that do apply to all automation endeavors.

In this post, I’ll give you five network automation tips and tricks to get clarity around your automation decisions and reduce any friction that may be inhibiting (further) adoption of network automation.

1. Choose whether you want flexibility or simplicity

Automating Continue reading