Keeping It Classless

Author Archives: Keeping It Classless

Open Source Routing: Practical Lab

Earlier, I wrote about some interesting open source routing software that I’ve been exploring lately. In this post, I’ll provide you with some tools to get this lab running on your lab, using Vagrant and Ansible.

In this post, I’ll be using VirtualBox, and also Ansible and Vagrant. For this purpose, I’m assuming you’re at least somewhat familiar with these tools.

Please checkout my GitHub repository for access to the latest versions of all of the files we’ll discuss below - and an easy way to spin all of this up yourself.

Topology

First, here’s the topology we’ll be working with.

All “circuits” are implemented using VirtualBox host networks, described in the Vagrantfile:

# -*- mode: ruby -*-
# vi: set ft=ruby :

VAGRANTFILE_API_VERSION = "2"
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
 
  config.vm.box = "trusty64"
  config.vm.box_url = "http://cloud-images.ubuntu.com/vagrant/trusty/current/trusty-server-cloudimg-amd64-vagrant-disk1.box"
 
  config.vm.define "r1" do |r1|
    r1.vm.host_name = "r1"
    r1.vm.network "private_network",
                         ip: "192.168.12.11",
                         virtualbox__intnet: "01-to-02"
    r1.vm.network "private_network",
                         ip: "192.168.31.11",
                         virtualbox__intnet: "03-to-01"
    r1.vm.network "private_network",
                         ip: "1.1.1.10",
                         virtualbox__intnet: "Network to Advertise"
    r1.vm.provision "ansible" do |ansible|
      ansible.playbook = "r1.yml"
     Continue reading

Open Source Routing: Practical Lab

Earlier, I wrote about some interesting open source routing software that I’ve been exploring lately. In this post, I’ll provide you with some tools to get this lab running on your lab, using Vagrant and Ansible.

In this post, I’ll be using VirtualBox, and also Ansible and Vagrant. For this purpose, I’m assuming you’re at least somewhat familiar with these tools.

Please checkout my GitHub repository for access to the latest versions of all of the files we’ll discuss below - and an easy way to spin all of this up yourself.

Topology

First, here’s the topology we’ll be working with.

All “circuits” are implemented using VirtualBox host networks, described in the Vagrantfile:

# -*- mode: ruby -*-
# vi: set ft=ruby :

VAGRANTFILE_API_VERSION = "2"
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
 
  config.vm.box = "trusty64"
  config.vm.box_url = "http://cloud-images.ubuntu.com/vagrant/trusty/current/trusty-server-cloudimg-amd64-vagrant-disk1.box"
 
  config.vm.define "r1" do |r1|
    r1.vm.host_name = "r1"
    r1.vm.network "private_network",
                         ip: "192.168.12.11",
                         virtualbox__intnet: "01-to-02"
    r1.vm.network "private_network",
                         ip: "192.168.31.11",
                         virtualbox__intnet: "03-to-01"
    r1.vm.network "private_network",
                         ip: "1.1.1.10",
                         virtualbox__intnet: "Network to Advertise"
    r1.vm.provision "ansible" do |ansible|
      ansible.playbook = "r1.yml"
     Continue reading

Open Source Routing: Practical Lab

Earlier, I wrote about some interesting open source routing software that I’ve been exploring lately. In this post, I’ll provide you with some tools to get this lab running on your lab, using Vagrant and Ansible. In this post, I’ll be using VirtualBox, and also Ansible and Vagrant. For this purpose, I’m assuming you’re at least somewhat familiar with these tools. Please checkout my GitHub repository for access to the latest versions of all of the files we’ll discuss below - and an easy way to spin all of this up yourself.

Open Source Routing: A Comparison

I have been getting more interested in open-source networking software, and I figured it was time to write a post comparing some of the more popular open source projects in this space.

Not only do we have several options (which hasn’t always been the case) for running routing protocols in FOSS, but we also have a variety of use cases that are increasing in popularity (using BGP for SDN-type purposes, not just to do internet peering). So isn’t an idea limited to enthusiasts who like to spin their own router - this kind of software has very interesting large-scale applications as well.

This won’t be a comprehensive list, just the top three that I’ve been looking into. I also won’t be going into too much detail on how to set all this software up - I’m saving that for a follow-up post.

Quagga

Quagga is at the top of this list primarily because from my perspective, it is the most well-known. It is best to think of Quagga as a collection of smaller daemons, each with a specific task. This task may be to run a routing protocol like OSPF or BGP, or it may be something else.

In this Continue reading

Open Source Routing: A Comparison

I have been getting more interested in open-source networking software, and I figured it was time to write a post comparing some of the more popular open source projects in this space.

Not only do we have several options (which hasn’t always been the case) for running routing protocols in FOSS, but we also have a variety of use cases that are increasing in popularity (using BGP for SDN-type purposes, not just to do internet peering). So isn’t an idea limited to enthusiasts who like to spin their own router - this kind of software has very interesting large-scale applications as well.

This won’t be a comprehensive list, just the top three that I’ve been looking into. I also won’t be going into too much detail on how to set all this software up - I’m saving that for a follow-up post.

Quagga

Quagga is at the top of this list primarily because from my perspective, it is the most well-known. It is best to think of Quagga as a collection of smaller daemons, each with a specific task. This task may be to run a routing protocol like OSPF or BGP, or it may be something else.

In this Continue reading

Double Parentheses in Python

Python is one of the easiest programming languages to learn, because of it’s inherent flexibility. (This can be a good thing as well as a bad thing.)

One example of Python’s flexibility is the double parentheses. Take the following snippet for example:

print funcwrapper(3)(2)

Even an inexperienced programmer should be able to make sense of most of this. Reading from left to right, it looks like we want to print the output of a function, and we’re passing an integer - 3 - to that function. However, the second pair of parentheses doesn’t quite make sense.

This notation is different from what we would do if we wanted to pass two arguments to a function; in that case, we’d put them all inside a single pair of parentheses and separate them via commas:

print funcwrapper(3, 2)

So what does the first example using two pairs of parentheses accomplish?

The use of a double parentheses is actually an indicator of one of Python’s coolest features - and that is that functions are themselves, objects! What does this mean?

Let’s work our way up to the snippet above by first defining a very simple function - something that takes an integer Continue reading

Double Parentheses in Python

Python is one of the easiest programming languages to learn, because of it’s inherent flexibility. (This can be a good thing as well as a bad thing.) One example of Python’s flexibility is the double parentheses. Take the following snippet for example: print funcwrapper(3)(2) Even an inexperienced programmer should be able to make sense of most of this. Reading from left to right, it looks like we want to print the output of a function, and we’re passing an integer - 3 - to that function.

Open Source Routing: A Comparison

I have been getting more interested in open-source networking software, and I figured it was time to write a post comparing some of the more popular open source projects in this space. Not only do we have several options (which hasn’t always been the case) for running routing protocols in FOSS, but we also have a variety of use cases that are increasing in popularity (using BGP for SDN-type purposes, not just to do internet peering).

A New Home: Looking Back

I have moved to a new blogging platform! The timing was interesting, since the wordpress installation on which Keeping It Classless has operated for so long is about 5 years old (I operated on an older domain before Keeping It Classless was born).

WOW. Five years is a long time in blog years. I could not have possibly predicted back then what this blog would do for me. In going over these old posts, I saw a very interesting progression of my own skillsets and mentality, and I figured I’d share. Call it a thank you for helping me grow the past 5 years. Please forgive the length of this post, but I wanted to make sure to call out everything of significance.

It’s also been crazy to witness the change in writing style. Early on I was not shy about using idioms, memes, and Borat references in blog posts, and now - while I am still humorous from time to time - I am a little more formal and succinct. Another way of looking at it is that early on, there was very little difference between the way that I wrote and the way that I spoke. Today, there Continue reading

A New Home: Looking Back

I have moved to a new blogging platform! The timing was interesting, since the wordpress installation on which Keeping It Classless has operated for so long is about 5 years old (I operated on an older domain before Keeping It Classless was born). WOW. Five years is a long time in blog years. I could not have possibly predicted back then what this blog would do for me. In going over these old posts, I saw a very interesting progression of my own skillsets and mentality, and I figured I’d share.

Moving Soon!

I would like to take the opportunity to let you all know that Keeping It Classless will be moving to a different blogging platform in the near future. For the vast majority of you, this will not be a problem. My intent is to keep as much as possible consistent between moves.

However, some of you subscribe to my blog using some WordPress-specific features such as email subscription, as well as following me through the WordPress service itself. After the move, these services will have no way of being updated. If this applies to you, please check out the following options:

I will continue to link to each new blog post to my social media accounts, such as Twitter, Facebook, Google+, and LinkedIn. Follow me at whichever you prefer, and you’ll get all new posts in the relevant news feed. I will continue to provide an RSS feed at http://keepingitclassless.net/feed/. Currently this redirects to feedburner, which is likely what you have in your RSS reader, if you’ve already done this. The transition away from WordPress will break this automatic redirection, but don’t worry – feedburner will continue to deliver post updates to you, at least until I move off Continue reading

Moving Soon!

I would like to take the opportunity to let you all know that Keeping It Classless will be moving to a different blogging platform in the near future. For the vast majority of you, this will not be a problem. My intent is to keep as much as possible consistent between moves. However, some of you subscribe to my blog using some WordPress-specific features such as email subscription, as well as following me through the WordPress service itself.

SDN: Integration over Manipulation

I’d like to briefly express a sentiment that I pondered after listening to another one of Ivan’s great podcasts, specifically regarding the true value of a software-defined network approach. The statement was made that ACLs are terrible representations of business policy. This is not inaccurate, but the fact remains that ACLs are currently the de facto representation of business policy on a network device. The “network team” gets a request from an application team to “fix the firewall”, and the policy that is applied to enable that application typically results in an ACL change.

If you’ve ever been in this situation, you likely realize this entire process probably takes some time. Either the application team doesn’t know what exactly needs to be changed, or the network team is too busy, or both. Clearly, there’s a problem. And more often than not, this discussion becomes all about the forwarding architecture.

Oh yes, with old-school ACLs we could only match on a few things - IP subnets, TCP ports, that's about it. But now with OpenFlow - we can match on **EtherType**!! We're saved!!

Don’t be misled - the value of an SDN architecture does not lie in the fact that we can do Continue reading

SDN: Integration over Manipulation

I’d like to briefly express a sentiment that I pondered after listening to another one of Ivan’s great podcasts, specifically regarding the true value of a software-defined network approach. The statement was made that ACLs are terrible representations of business policy. This is not inaccurate, but the fact remains that ACLs are currently the de facto representation of business policy on a network device. The “network team” gets a request from an application team to “fix the firewall”, and the policy that is applied to enable that application typically results in an ACL change.

The Two “Network As Code” Domains

You’ve probably heard the term “network programmability” at this point. You probably also heard it equated to anything to do with code, automation, and networking. This was not always the case.

Network programmability really first hit the big time back in 2011 in the early days of the public OpenFlow discussion. That phrase was almost universally understood to be a data plane concept - because it was describing the revolutionary ideas brought up by abstracting away a forwarding pipeline. “You mean I can program my network device directly?” Network programmability.

I was inspired by a thread that my friend Josh kicked off with this tweet:

An interesting dialogue followed, and I felt compelled to address the problem caused by marketing departments muddying the waters of what would otherwise be a very simple idea.

Now obviously it’s too late to “right the wrong” that resulted from marketing and journalism engines chugging at full steam trying to make every technical term and phrase utterly useless. However, I would like Continue reading

The Two “Network As Code” Domains

You’ve probably heard the term “network programmability” at this point. You probably also heard it equated to anything to do with code, automation, and networking. This was not always the case. Network programmability really first hit the big time back in 2011 in the early days of the public OpenFlow discussion. That phrase was almost universally understood to be a data plane concept - because it was describing the revolutionary ideas brought up by abstracting away a forwarding pipeline.

Three Tips for Technical Blogging

From time to time, I’m asked by new or potential technical bloggers for advice on how to get into writing, or how to overcome some kind of mental reservation that he/she may have.

It’s actually somewhat ironic - I still suffer from many of the same issues that I suffered from back before Keeping It Classless existed.

So, truth be told, I constantly remind myself of the same advice that I give to the bloggers-to-be that ask me for advice. It’s high time that I open the kimono a little bit and hopefully help someone in the process. Here are my top three tips for technical bloggers - whether you’re just getting started, or if you’re already fairly established but maybe hitting some blockage.

Know Why You Do It

Be keenly aware of the motivation(s) that drive your blogging. Write them down. Look at them every day. Keeping these in mind should be your primary source of energy when writing about a technical topic. Unless blogging is your actual job (in which case this Continue reading

Three Tips for Technical Blogging

From time to time, I’m asked by new or potential technical bloggers for advice on how to get into writing, or how to overcome some kind of mental reservation that he/she may have. It’s actually somewhat ironic - I still suffer from many of the same issues that I suffered from back before Keeping It Classless existed. I have been having some serious "Newbie Blogger" issues last few weeks. Ironically, I feel compelled to write about them.

[SDN Protocols] Part 5 – NETCONF

For those that followed my SDN Protocols series last summer, you might have noticed a missing entry: NETCONF. This protocol has actually existed for some time (the original now-outdated specification was published in 2006), but is appearing more often, especially in discussions pertaining to network automation. The current, updated specification - RFC6241 - covers a fairly large amount of material, so I will attempt to condense here.

NETCONF operates at the management layer of the network, and therefore plays a role similar to that of OVSDB. This is in contrast to protocols like OpenFlow  which operate at the control plane.

A key difference between NETCONF and other management protocols (including SNMP) is that NETCONF is built around the idea of a transaction-based configuration model. The NETCONF specification provides for some optional device capabilities aimed at assisting operators with the lifecycle of configuring a network device, such as rolling back a configuration upon an error. Unfortunately, not all network devices support such capabilities, but the protocol was built to make it easier to discover what kind of capabilities a network device can support.

Configuration Datastores

Before getting into the semantics of the NETCONF protocol itself, it’s worth briefly jumping ahead to address the Continue reading

[SDN Protocols] Part 5 – NETCONF

For those that followed my SDN Protocols series last summer, you might have noticed a missing entry: NETCONF. This protocol has actually existed for some time (the original now-outdated specification was published in 2006), but is appearing more often, especially in discussions pertaining to network automation. The current, updated specification - RFC6241 - covers a fairly large amount of material, so I will attempt to condense here. NETCONF operates at the management layer of the network, and therefore plays a role similar to that of OVSDB.
1 … 4 5 6 7 8 … 21