Artificial Intelligence and Deep Learning - Tensorflow

This is a tool that someone told me about which could be a good way to get hands-on started with AI, should the spirit move you to do so.

Tensorflow

FPGA

FPGA stands for Field Programmable Gate Array.

Per Wikipedia definition, "an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence the term field-programmable"

https://en.wikipedia.org/wiki/Field-programmable_gate_array

Hairpin NAT

A lot of folks don't understand Hairpin NAT, meaning what it is, why it exists, or the specific use cases in which it applies.

This is an awesome site that explains it nicely - although you have to read the very very last paragraph to get to the bottom of it:

Hairpin NAT Explained

NOSQL databases - are we taking a step backwards?

One of the solutions I am looking at happens to be utilizing Cassandra, a NOSQL database project from the Apache Foundation.

I am pretty deep with SQL databases, but not so much with NOSQL databases. I may have done a couple remark-based blogs on the topic of NOSQL databases in the past, but really have not looked into them in any kind of depth.

However, in noticing a java process running and realizing it was Cassandra, I went to the Cassandra website and started to take a closer look. When I went to the site and clicked:

• Documentation
• Architecture
• Overview

I wound up getting a TODO page. Sheez. That's absolutely unacceptable and ridiculous.

So, if I want more introductory information, I will probably have to blog surf.

But, I did find this very interesting Quora page, entitled: What are the pros and cons of the Cassandra database? It can be found at this link: What-are-the-pros-and-cons-of-using-the-Cassandra-database?

This reminds me of the old Object Oriented database days, when products like Versant hit the scene. Speedy databases that made it easy to get your data IN, but when it came to getting it OUT, it was an absolute nightmare.

There are no aggregate functions (SUM, AVG, etc). No table joins or filters. It uses a CSQL query syntax that looks somewhat like SQL, but will result in confusion because it does not naturally support ANSI-SQL concepts.

Makes me wonder. Are we taking a big step backwards with these kinds of databases becoming so pervasive?

There are other container platforms besides Docker? Like LXC?

I'm relatively new to containers technology. I didn't even realize there were alternatives to Docker (although I hadn't really thought about it).

Colleague of mine knew this though, and sent me this interesting link.

https://robin.io/blog/linux-containers-comparison-lxc-docker/

This link is a discussion about a more powerful container platform called LXC, which could be used as an alternative to Docker.

I'm still in the process of learning about it. Will update the blog later.

Data Plane Development Kit (DPDK)

I kept noticing that a lot of the carrier OEMs are implementing their "own" Virtual Switches.

I wasn't really sure why, and decided to look into the matter.  After all, there is a fast-performing OpenVSwitch, which while fairly complex, is powerful, flexible, and, well, open source.

Come to learn, there is actually a faster way to do networking than with native OpenVSwitch.

OpenVSwitch minimizes all of the context switching between user space and kernel space when it comes to taking packets from a physical port, and forwarding those packets to virtualized network functions (VNF) and back. 

But - DPDK provides a means to circumvent the kernel, and have practically everything in user space interacting directly to the hardware (bypassing the kernel).

This is fast, indeed, if you can do this. But it bypasses all of the purposes of a kernel network stack, so there has to be some sacrifice (which I need to look into and understand better).  One of the ways it bypasses the kernel is through Direct Memory Access (DMA), based on some limited reading (frankly, reading it and digesting it and understanding it usually requires several reads and a bit of concentration as this stuff gets very complex very fast).

The other question I have, is that if DPDK is bypassing the kernel en route to a physical NIC, what about other kernel-based networking services that are using that same NIC? How does that work?

I've got questions. More questions.

But up to now, I was unaware of this DPDK and its role in the new generation of virtual switches coming out. Even OpenVSwitch itself has a DPDK version.

Service Chaining and Service Function Forwarding

I had read about the concept of service chaining and service forward functioning early on, in a SD-WAN / NFV book that I had read, which at the time was ahead of its time.  I hadn't actually SEEN this, or implemented it, until just recently on my latest project.

Now, we have two "Cloud" initiatives going on at the moment, plus one that's been in play for a while.

1. Ansible - chosen over Puppet, and Chef in a research initiative, this technology is essentially used to automate the deployment and configurations of VMs (LibVirt KVMs to be accurate). 
• But there is no service chaining or service function forwarding in this.
2. OpenStack / OpenBaton - this is a project to implement Service Orchestration - using ETSI MANO descriptors to "describe" Network Functions, Services, etc.
• But we only implemented a single VNF, and did not chain them together with chaining rules, or forwarding rules. 
3. Kubernetes - this is a current project to deploy technology into containers. And while there is reliance and dependencies between the containers, including scaling and autoscaling, I would not say that we have implemented Service Chaining or Service Function Forwarding the way it was conceptualized academically and in standards.

The latest project I was involved with DID make use of Service Chaining and Service Function Forwarding.  We had to deploy a VNF onto a Ciena 3906mvi device, which had a built-in Network Virtualization module that ran on a Linux operating system. This ran "on top" of an underlying Linux operating system that dealt with the more physical aspects of the box (fiber ports, ethernet ports both 1G and 100G, et al).

It's my understanding that the terms Service Chaining and Service Function Forwarding have their roots in the YANG reference model. https://en.wikipedia.org/wiki/YANG

This link has a short primer on YANG. 

http://www.tail-f.com/wordpress/wp-content/uploads/2014/02/Tail-f-Instant-YANG.pdf

YANG is supposed to extend a base set of network operations that are spelled out in a standard called NETCONF (feel free to research this - it and YANG are both topics in and of themselves).

In summary, it was rather straightforward to deploy the VNF. You had to know how to do it on this particular box, but it was rather straightforward. What was NOT straightforward, was figuring out how you wanted your traffic to flow, and configuring the Service Chaining and Service Function Forwarding rules.

What really hit home to me is that the Virtual Switch (fabric) is the epicenter of the technology. Without knowing how these switches are configured and inter-operate, you can't do squat - automated, manual, with descriptors, or not. And this includes troubleshooting them.

Now with Ciena, theirs on this box was proprietary. So you were configuring Flooding Domains, Ports, Logical Ports, Traffic Classifiers, VLANs, etc.  This is the only way you can make sure your traffic is hop-scotching around the box the way you want it to, based on rules you specify.

Here is another link on Service Chaining and Service Function Forwarding that's worth a read.

http://www.tail-f.com/wordpress/wp-content/uploads/2014/02/Tail-f-Instant-YANG.pdf