OpenDaylight Tutorial: Connecting OpenFlow Switches
In this excerpt from "OpenDaylight Cookbook," learn how to connect an OpenFlow switch to the open source SDN controller.
Multi-tier load-balancing with Linux
A common solution to provide a highly-available and scalable service is to insert a load-balancing layer to spread requests from users to backend servers.1 We usually have several expectations for such a layer:
- scalability
- It allows a service to scale by pushing traffic to newly provisioned backend servers. It should also be able to scale itself when it becomes the bottleneck.
- availability
- It provides high availability to the service. If one server becomes unavailable, the traffic should be quickly steered to another server. The load-balancing layer itself should also be highly available.
- flexibility
- It handles both short and long connections. It is flexible enough to offer all the features backends generally expect from a load-balancer like TLS or HTTP routing.
- operability
- With some cooperation, any expected change should be seamless: rolling out a new software on the backends, adding or removing backends, or scaling up or down the load-balancing layer itself.
The problem and its solutions are well known. From recently published articles on the topic, “Introduction to modern network load-balancing and proxying” provides an overview of the state of the art. Google released “Maglev: A Fast and Reliable Software Network Load Balancer” describing their Continue reading
Why is Network Automation So Hard?
This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.
Every now and then someone asks me “Why are we making so little progress on network automation? Why does it seem so hard?”
There are some obvious reasons:
- Tightly-coupled components and humongous blast radius;
- Lack of good tools and programming interfaces;
- Lack of transactional consistency (in some cases even simple commits);
However, there’s a bigger elephant in the room: every network is a unique snowflake.
Read more ...Pixie: a system for recommending 3+ billion items to 200+ million users in real-time
Pixie: a system for recommending 3+ billion items to 200+ million users in real-time Eksombatchai et al., WWW’18
(If you don’t have ACM Digital Library access, the paper can be accessed either by following the link above directly from The Morning Paper blog site, or from the WWW 2018 proceedings page).
Pinterest is a visual catalog with several billion pins, which are visual bookmarks containing a description, a link, and an image or a video. A major problem faced at Pinterest is to provide personalized, engaging, and timely recommendations from a pool of 3+ billion items to 200+ million monthly active users.
Stating the obvious, 3 billion or so items is a lot to draw recommendations from. This paper describes how Pinterest do it. One of the requirements is that recommendations need to be calculated in real-time on-demand. I’m used to thinking about the shift from batch to real-time in terms of improved business responsiveness, more up-to-date information, continuous processing, and so on. Pinterest give another really good reason which is obvious with hindsight, but hadn’t struck me before: when you compute recommendations using a batch process, you have to calculate the recommendations for every user Continue reading
Facebook Unveils Network Load Balancer, Provisioning Tool
Social media giant releases details about its Katran load balancing software, which it's open sourcing, and its Zero-Touch network provisioning system.
Securing the Multi-Cloud: It Takes a Village
Even enterprises not in a multi-cloud environment must begin making their security decisions with it in mind. If they don’t, they risk some of their decisions quickly becoming obsolete.
Pivot3 Adds Live Migration Across AWS, Microsoft Azure, Google Cloud
The hyperconverged infrastructure vendor partnered with CloudEndure, whose software provides disaster recovery and live migration technology, for the new services.
Regular Expression for Network Engineer Part-1
A regular expression is set of pattern used to define certain amount of text. An powerful tool in any scripting language to match any pattern.
Lets have a look , how regular expression can be used in Python to solves the problem. Module “re’ is imported in python to support regular expression .
<< import re >>
[ ] – its for specifying character class, individual char or range of character can be mached .
- [123] will match any of the character ‘1’,’2′,’3′
- [1-3] will match any of the character ‘1’,’2′,’3′
- [a-d] will match any of the character a,b,c,d
- [a-z] will match lowercase
- [A-Z] will match uppercase
- [^6] will match any character except 6
- [a-zA-Z0-9] will match any alphanumeric character
- [^a-zA-Z0-9] will not match any alphanumeric character
- [a-zA-Z0-9] is equivalent to \w
- [^a-zA-Z0-9] is equivalent to \W
- [0-9] is equivalent to \d
- [^0-9] is equivalent to \D
- [ \t\n\r\f\v] is equivalent to \s
- [ ^ \t\n\r\f\v] is equivalent to \S
. – Period character ,use for matching any single charcter
- EXAMPLE :
[code language=”python”]
In [225]: ip =’10.20.30.40′
In [226]: re.search(r”.”,ip)
Out[226]:<_sre.SRE_Match object; span=(0, 1), match=’1’_>
In [227]: re.search(r”.”,ip).group(0)
Out[227]: ‘1’
Regular Expression for Network Engineer Part-1
A regular expression is set of pattern used to define certain amount of text. An powerful tool in any scripting language to match any pattern. Lets have a look , how regular expression can be used in Python to solves the problem. Module “re’ is imported in python to support regular expression . << import […]OpenStack Makes its Open Source CI/CD Platform Available to the Wider World
OpenStack has been decoupling Zuul from OpenStack-specific systems to make the software available to more developers.
Introducing: The Cloudflare All-Stars Fantasy League
Baseball season is well underway, and to celebrate, we're excited to introduce the Cloudflare All-Stars Fantasy League: a group of fictitious sports teams that revolve around some of Cloudflare’s most championed products and services. Their mission? To help build a better Internet.
Cloudflare HQ is located just a block away from the San Francisco Giants Stadium. Each time there's a home game, crowds of people walk past Cloudflare's large 2nd street windows and peer in to the office space. The looks in their eyes scream: "Cloudflare! Teach me about your products while giving me something visually stimulating to look at!"
They asked. We listened.
The design team saw a creative opportunity, seized it, and hit it out of the park. Inspired by the highly stylized sports badges and emblems of some real-life sports teams, we applied this visual style to our own team badges. We had a lot of fun coming up with the team names, as well as figuring out which visuals to use for each.
For the next few months, the Cloudflare All-Stars teams will be showcased within the large Cloudflare HQ windows facing 2nd street and en route to Giants Stadium. Feel free to Continue reading
Spectre and Meltdown Chip Flaws Back From the Dead as ‘Variant 4’
Microsoft and Google security researchers disclosed the new bugs, which affect Intel, AMD, and ARM processors.
Juniper, Red Hat Tighten Integration to Fend Off VMware
The goal is to help enterprises more easily take advantage of open cloud systems.
Masergy Makes Its SD-WAN More Agile With Bandwidth On-Demand
Customers can now scale their broadband connections up and down on a schedule or in real-time.
Imperiled ZTE May Get a Reprieve as China, U.S. Work on Deal to Remove Ban
The Trump administration is considering lifting the ban in exchange for a removal of tariffs on products from the U.S. farm belt and reduced tariffs on imported U.S. automobiles.