Every now and then a smart person decides to walk away from their competence zone, and start spreading pointless clickbait opinions like BGP is a hot mess.
Like any other technology, BGP is just a tool with its advantages and limitations. And like any other tool, BGP can be used sloppily… and that’s what’s causing the various problems and shenanigans everyone is talking about.
Just in case you might be interested in facts instead of easy-to-digest fiction:
Read more ...Russ White wrote a great blog post explaining why you have to understand the problem you’re solving instead of blindly believing the $vendor slide deck… or as I said a long time ago, think about how you’ll troubleshoot your network in because you won’t be able to reformat it once it crashes.
Read more ...I’ve seen successful public (infrastructure) cloud deployments… but also spectacular failures. The difference between the two usually comes down to whether the team deploying into a public cloud environment realizes they’re dealing with an unfamiliar environment and acts accordingly.
Please note that I’m not talking about organizations migrating their email to Office 365. While that counts as public cloud deployment when an industry analyst tries to paint a rosy picture of public cloud acceptance, I’m more interested in organizations using compute, storage, security and networking public cloud infrastructure.
Read more ...One of my readers sent me a question along these lines…
VXLAN Network Identifier is 24 bit long, giving 16 us million separate segments. However, we have to map VNI into VLANs on most switches. How can we scale up to 16 million segments when we have run out of VLAN IDs? Can we create a separate VTEP on the same switch?
VXLAN is just an encapsulation format and does not imply any particular switch architecture. What really matters in this particular case is the implementation of the MAC forwarding table in switching ASIC.
Read more ...After publishing the Disaster Recovery Faking, Take Two blog post (you might want to read that one before proceeding) I was severely reprimanded by several people with ties to virtualization vendors for blaming virtualization consultants when it was obvious the firewall clusters stretched across two data centers caused the total data center meltdown.
Let’s chase that elephant out of the room first. When you drive too fast on an icy road and crash into a tree who do you blame?
For whatever reason some people love to blame the tires ;)
Read more ...Last Thursday morning I found this gem in my Twitter feed (courtesy of Stefan de Kooter)
Greg Cusanza in #BRK3192 just announced #Azure Extended Network, for stretching Layer 2 subnets into Azure!
As I know a little bit about how networking works within Azure, and I’ve seen something very similar a few times in the past, I was able to figure out what’s really going on behind the scenes in a few seconds… and got reminded of an old Russian joke I found somewhere on Quora:
Read more ...The previous videos from the How Networks Really Work webinar covered an overview of networking challenges and the importance of networking layers.
Now it’s time to put it all together.
You need free ipSpace.net subscription to watch the video, or a paid ipSpace.net subscriptions to watch the whole webinar.
A few days ago we published the content outline for our Networking in Public Clouds online course.
We’ll start with the basics, explore the ways to automate cloud deployments (after all, you wouldn’t want to repeat the past mistakes and configure everything with a GUI, would you?), touch on compute and storage infrastructure, and the focus on the networking aspects of public cloud deployments including:
Read more ...A Network Artist left a lengthy comment on my Brief History of VMware NSX blog post. He raised a number of interesting topics, so I decided to write my replies as a separate blog post.
Using Geneve is an interesting choice to be made and while the approach has it’s own Pros and Cons, I would like to stick to VXLAN if I were to recommend to someone for few good reasons.
The main reason I see for NSX-T using Geneve instead of VXLAN is the need for additional header fields to carry metadata around, and to implement Network Services Header (NSH) for east-west service insertion.
Read more ...Imagine you want to create a Jinja2 report that includes only a select subset of elements of a data structure… and want to have header, footer, and element count in that report.
Traditionally we’d solve that challenge with an extra variable, but as Jinja2 variables don’t survive loop termination, the code to do that in Jinja2 gets exceedingly convoluted.
Fortunately, Jinja2 provides a better way: using a conditional expression to select the elements you want to iterate over.
A friend of mine sent me a short message including…
There is a number of products that recently arrived or are coming to market using group encryption systems for IP networks, but are (understandably) not using IPsec.
… which triggered an old itch of mine caused by the “We don’t need no IETF standards, code is king” stupidity.
Read more ...During the last Tech Field Day Extra @ CLEUR, one of the fellow delegates asked me about my opinion on technology X (don’t remember the details, it was probably one of those over-hyped four-letter technologies). As usual, I started explaining the drawbacks, and he quickly stopped me with a totally unexpected question: “Why do you always tend to be so negative?”
That question has been haunting me for months… and here are a few potential answers I came up with.
Read more ...In November 2019 we’ll continue the crazy pace of autumn 2019 webinar season:
I don’t remember who pointed me to the excellent How Complex Systems Fail document. It’s almost like RFC1925 – I could quote it all day long, and anyone dealing with large mission-critical distributed systems (hint: networks) should read it once a day ;))
Enjoy!
Years ago Dan Hughes wrote a great blog post explaining how expensive TCP is. His web site is long gone, but I managed to grab the blog post before it disappeared and he kindly allowed me to republish it.
If you ask a CIO which part of their infrastructure costs them the most, I’m sure they’ll mention power, cooling, server hardware, support costs, getting the right people and all the usual answers. I’d argue one the the biggest costs is TCP, or more accurately badly implemented TCP.
Read more ...One of my subscribers was interested in trying out whitebox solutions. He wrote:
What open source/whitebox software/hardware should I look at if I wanted to build a leaf-and-spine VXLAN/EVPN/BGP data center.
I don’t think you can get a fully-open-source solution because the ASIC manufacturers hide their SDK behind a mountain of NDAs (that strategy must make perfect sense – after all, it generated such awesome PR for NVIDIA). Anyway, the closest you can get (AFAIK) if you're a mere mortal is Cumulus Linux, and you just choose any whitebox hardware off their Hardware Compatibility List.
Read more ...Seth Godin published an interesting article on the value of hard work (and what hard work really is). Go and read it first, then we’ll translate it into networking terms.
Already back? Good, let’s go.
The first worker is a traditional networking technician (it wouldn’t be fair to call him an engineer) – he’s busy configuring VLANs, ACLs, firewall rules… the whole day.
Read more ...Everyone is talking about FRRouting suite these days, while hidden somewhere in the background OpenBGPD has been making continuous progress for years. Interestingly, OpenBGPD project was started for the same reason FRR was forked - developers were unhappy with Zebra or Quagga routing suite and decided to fix it.
We discussed the history of OpenBGPD, its current deployments and future plans with Claudio Jeker, one of the main OpenBGPD developers, in Episode 106 of Software Gone Wild.
You probably heard me say “networking engineer encountering a public cloud feels like Alice in Wonderland” - packet forwarding works in a different way in every public cloud, subnets are a mix between routed interfaces and VRFs, you cannot change IP addresses without involving the orchestration system…
We covered the networking aspects of Amazon Web Services and Azure in our cloud webinars, but you might need a bigger picture:
Read more ...When I first met Cumulus Networks engineers (during NFD9) their focus on simplifying switch configurations totally delighted me (video).
After solving the BGP configuration challenge (could you imagine configuring BGP in a leaf-and-spine fabric with just a few commands in 2015), they did the same thing with EVPN configuration, where they decided to implement the simplest possible design (EBGP-only fabric running EBGP EVPN sessions on leaf-to-spine links), resulting in another round of configuration simplicity.
Read more ...