Public Cloud Behind-the-Scenes Magic
One of my subscribers sent me this question after watching the networking part of Introduction to Cloud Computing webinar:
Does anyone know what secret networking magic the Cloud providers are doing deep in their fabrics which are not exposed to consumers of their services?
TL&DR: Of course not… and I’m guessing it would be pretty expensive if I knew and told you.
However, one can always guess based on what can be observed (see also: AWS networking 101, Azure networking 101).
Repost: Using MP-TCP to Utilize Unequal Links
In the Does Unequal-Cost Multipathing Make Sense blog post I wrote (paraphrased):
The trick to successful utilization of unequal uplinks is to use them wisely […] It’s how multipath TCP (MP-TCP) could be used for latency-critical applications like Siri.
Minh Ha quickly pointed out (some) limitations of MP-TCP and as is usually the case, his comment was too valuable to be left as a small print at the bottom of a blog post.
Intuitively I don’t necessarily agree with all of his conclusions, but don’t know enough to have a qualified opinion.
Repost: Using MP-TCP to Utilize Unequal Links
In the Does Unequal-Cost Multipathing Make Sense blog post I wrote (paraphrased):
The trick to successful utilization of unequal uplinks is to use them wisely […] It’s how multipath TCP (MP-TCP) could be used for latency-critical applications like Siri.
Minh Ha quickly pointed out (some) limitations of MP-TCP and as is usually the case, his comment was too valuable to be left as a small print at the bottom of a blog post.
Intuitively I don’t necessarily agree with all of his conclusions, but don’t know enough to have a qualified opinion.
Using YAML Instead of Excel in Network Automation Solutions
One of the attendees of our network automation course asked a question along these lines:
In a previous Ansible-based project I used Excel sheet to contain all relevant customer data. I converted this spreadsheet using python (xls_to_fact) and pushed the configurations to network devices accordingly. I know some people use YAML to define the variables in Git. What would be the advantages of doing that over Excel/xsl_to_fact?
Whenever you’re choosing a data store for your network automation solution you have to consider a number of aspects including:
Using YAML Instead of Excel in Network Automation Solutions
One of the attendees of our network automation course asked a question along these lines:
In a previous Ansible-based project I used Excel sheet to contain all relevant customer data. I converted this spreadsheet using python (xls_to_fact) and pushed the configurations to network devices accordingly. I know some people use YAML to define the variables in Git. What would be the advantages of doing that over Excel/xsl_to_fact?
Whenever you’re choosing a data store for your network automation solution you have to consider a number of aspects including:
Azure Route Server: Behind the Scenes
Last week I described the challenges Azure Route Server is supposed to solve. Now let’s dive deeper into how it’s implemented and what those implementation details mean for your design.
The whole thing looks relatively simple:
Azure Route Server: Behind the Scenes
Last week I described the challenges Azure Route Server is supposed to solve. Now let’s dive deeper into how it’s implemented and what those implementation details mean for your design.
The whole thing looks relatively simple:
Worth Reading: Modules, Monoliths, and Microservices
If you want to grow beyond being a CLI (or Python) jockey, it’s worth trying to understand things work… not only how frames get from one end of the world to another, but also how applications work, and why they’re structured they way they are.
Daniel Dib recently pointed out another must-read article in this category: Modules, monoliths, and microservices by Avery Pennarun – a wonderful addition to my distributed systems resources.
Worth Reading: Modules, Monoliths, and Microservices
If you want to grow beyond being a CLI (or Python) jockey, it’s worth trying to understand things work… not only how frames get from one end of the world to another, but also how applications work, and why they’re structured they way they are.
Daniel Dib recently pointed out another must-read article in this category: Modules, monoliths, and microservices by Avery Pennarun – a wonderful addition to my distributed systems resources.
Video: Cisco SD-WAN Routing Design
After reviewing Cisco SD-WAN policies, it’s time to dig into the routing design. In this section, David Penaloza enumerated several possible topologies, types of transport, their advantages and drawbacks, considerations for tunnel count and regional presence, and what you should consider beforehand when designing the solution from the control plane’s perspective.
You need Free ipSpace.net Subscription to watch the video.
Video: Cisco SD-WAN Routing Design
After reviewing Cisco SD-WAN policies, it’s time to dig into the routing design. In this section, David Penaloza enumerated several possible topologies, types of transport, their advantages and drawbacks, considerations for tunnel count and regional presence, and what you should consider beforehand when designing the solution from the control plane’s perspective.
You need Free ipSpace.net Subscription to watch the video.
Topology- and Congestion-Driven Load Balancing
When preparing an answer to an interesting idea left as a comment to my unequal-cost load balancing blog post, I realized I never described the difference between topology-based and congestion-driven load balancing.
To keep things simple, let’s start with an easy leaf-and-spine fabric:
Topology- and Congestion-Driven Load Balancing
When preparing an answer to an interesting idea left as a comment to my unequal-cost load balancing blog post, I realized I never described the difference between topology-based and congestion-driven load balancing.
To keep things simple, let’s start with an easy leaf-and-spine fabric:
Azure Route Server: The Challenge
Imagine you decided to deploy an SD-WAN (or DMVPN) network and make an Azure region one of the sites in the new network because you already deployed some workloads in that region and would like to replace the VPN connectivity you’re using today with the new shiny expensive gadget.
Everyone told you to deploy two SD-WAN instances in the public cloud virtual network to be redundant, so this is what you deploy:
Azure Route Server: The Challenge
Imagine you decided to deploy an SD-WAN (or DMVPN) network and make an Azure region one of the sites in the new network because you already deployed some workloads in that region and would like to replace the VPN connectivity you’re using today with the new shiny expensive gadget.
Everyone told you to deploy two SD-WAN instances in the public cloud virtual network to be redundant, so this is what you deploy:
Interesting Tool: Schema Enforcer
It looks like JSON Schema is the new black. Last week I wrote about a new Ansible module using JSON Schema to validate data structures passed to it; a few weeks ago NetworkToCode released Schema Enforcer, a similar CLI tool (which means it’s easy to use it in any CI/CD pipeline).
Wondering why schema validation matters? Start here. See also: GIGO.
Here are just a few things Schema Enforcer can do:
Interesting Tool: Schema Enforcer
It looks like JSON Schema is the new black. Last week I wrote about a new Ansible module using JSON Schema to validate data structures passed to it; a few weeks ago NetworkToCode released Schema Enforcer, a similar CLI tool (which means it’s easy to use it in any CI/CD pipeline).
Wondering why schema validation matters? Start here. See also: GIGO.
Here are just a few things Schema Enforcer can do:
Implementing Layer-2 Networks in a Public Cloud
A few weeks ago I got an excited tweet from someone working at Oracle Cloud Infrastructure: they launched full-blown layer-2 virtual networks in their public cloud to support customers migrating existing enterprise spaghetti mess into the cloud.
Let’s skip the usual does everyone using the applications now have to pay for Oracle licenses and I wonder what the lock in might be when I migrate my workloads into an Oracle cloud jokes and focus on the technical aspects of what they claim they implemented. Here’s my immediate reaction (limited to the usual 280 characters, because that’s the absolute upper limit of consumable content these days):
Implementing Layer-2 Networks in a Public Cloud
A few weeks ago I got an excited tweet from someone working at Oracle Cloud Infrastructure: they launched full-blown layer-2 virtual networks in their public cloud to support customers migrating existing enterprise spaghetti mess into the cloud.
Let’s skip the usual does everyone using the applications now have to pay for Oracle licenses and I wonder what the lock in might be when I migrate my workloads into an Oracle cloud jokes and focus on the technical aspects of what they claim they implemented. Here’s my immediate reaction (limited to the usual 280 characters, because that’s the absolute upper limit of consumable content these days):
MUST READ: Systems Design Explains the World
The one and only Avery Pennarun (of the world in which IPv6 was a good design fame) is back with another absolutely-must-read article explaining how various archetypes apply to real-world challenges, including:
- Hierarchies and decentralization (and why decentralization is a myth)
- Chicken-and-egg problem (and why some good things fail)
- Second-system effect (or why it’s better to refactor than to rewrite)
- Innovator’s dilemma (or why large corporations become obsolete)
If you think none of these applies to networking, you’re probably wrong… but of course please write a comment if you still feel that way after reading Avery’s article.