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Category Archives for "Networking"

The Evolution of Network Programmability

This post is the “text” version of a talk I gave at Cisco Live US 2014 titled “SDN: People, Process, and Evolution“. While there is certainly some technical details involved here, this topic is really more of a philosophical one, and it is very near and dear to my heart as I talk with more folks about how networking is going to evolve in the years to come.

The Problem with Networking

Most of my readers would consider themselves network engineers – folks that live and breathe networking and everything that’s required to build them. Folks like you and I don’t really need to hear what’s wrong with networking, as we live it every day. However, for the sake of others that may be reading, let me provide a little context here.

Nearly everyone in the industry is hearing about how “networking is slow” with respect to provisioning time. We hear about how virtual machines can be instantiated in a few seconds (hell, application containers can be spun up in less than a second!) yet the really important network stuff like firewall or load balancer policies take forever. They’re not wrong – networking has never really been tightly Continue reading

Pylint Errors – Final Newline Missing

I recently ran into a slew of errors when using Pylint - a sort of “quality checker” for your Python code. If you haven’t used it yourself, I highly recommend you check it out – it WILL make you a better Python coder.(Thanks to Matt Stone for introducing me!)

This particular error is common if you forget to append a newline character to the end of your python script, but I was getting one for every single line of code in my program.

khalis:library Mierdin$ pylint ucs_getwwpns.py 
No config file found, using default configuration
C:  1, 0: Final newline missing (missing-final-newline)
C:  2, 0: Final newline missing (missing-final-newline)
C:  3, 0: Final newline missing (missing-final-newline)
C:  4, 0: Final newline missing (missing-final-newline)
C:  5, 0: Final newline missing (missing-final-newline)
C:  6, 0: Final newline missing (missing-final-newline)
C:  7, 0: Final newline missing (missing-final-newline)

You get the idea.

My code clearly has a newline character of some kind at the end, but perhaps it’s just not the right one. We need to see what newline character our editor is actually appending to the end of our lines.

For this, we’ll use the (*nix) “od” command, which dumps files Continue reading

Will End-to-End Service Management Standards and Tools Always Trail New SDN Technologies?

Will End-to-End Service Management Standards and Tools Always Trail New SDN Technologies?

by Brian Boyko, Technology Contributor - March 27, 2014

There’s an interesting Light Reading article by Carol Wilson talking about Ari Banerjee's research into end-to-end service management for SDN & NFV, and how Banerjee has shown that the European Telecommunications Standards Institute (ETSI) has failed to take into account hybrid virtualized and non-virtualized environments when drawing up their standards on virtualized service and network functions.  

In other words, the standards work in theory, but in practice, they're just too simple for real-world environments. Will end-to-end service management standards and tools always trail new SDN technologies? 

Here's an odd thing about technology development: it tends to come in five distinct stages. 

Stage 1: Can we do this thing?
Stage 2: How can we do this thing?
Stage 3: What's the best way to do this thing?
Stage 4: How do we make doing this thing easier?
Stage 5: How can we manage this thing? 

And of course, sometimes answering, "How do we make doing this thing easier?" and “How can we manage this thing?” starts with asking the question "Can we do this Continue reading

Healthy Paranoia Show 24: Down and Dirty with PCI DSS

Thanks for tuning in for another crime busting episode of Healthy Paranoia. Today, we’ll be getting down and dirty with some actual practitioners to discuss what’s wrong with PCI DSS. Joining me in the secret Healthy Paranoia hideout will be Mr. Stits, an actual PCI QSA. We also have Mrs. Dystie, expert in exploding crypto […]

Author information

Mrs. Y

Snarkitecht at Island of Misfit Toys

Mrs. Y is a recovering Unix engineer working in network security. Also the host of Healthy Paranoia and official nerd hunter. She likes long walks in hubsites, traveling to security conferences and spending time in the Bat Cave. Sincerely believes that every problem can be solved with a "for" loop. When not blogging or podcasting, can be found using up her 15 minutes in the Twittersphere or Google+ as @MrsYisWhy.
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The post Healthy Paranoia Show 24: Down and Dirty with PCI DSS appeared first on Packet Pushers Podcast and was written by Mrs. Y.

Pylint Errors – Final Newline Missing

I recently ran into a slew of errors when using Pylint - a sort of “quality checker” for your Python code. If you haven’t used it yourself, I highly recommend you check it out - it WILL make you a better Python coder.(Thanks to Matt Stone for introducing me!) This particular error is common if you forget to append a newline character to the end of your python script, but I was getting one for every single line of code in my program.

The Evolution of Network Programmability

This post is the “text” version of a talk I gave at Cisco Live US 2014 titled “SDN: People, Process, and Evolution”. While there is certainly some technical details involved here, this topic is really more of a philosophical one, and it is very near and dear to my heart as I talk with more folks about how networking is going to evolve in the years to come. The Problem with Networking Most of my readers would consider themselves network engineers - folks that live and breathe networking and everything that’s required to build them.

Pylint Errors – Final Newline Missing

I recently ran into a slew of errors when using Pylint - a sort of “quality checker” for your Python code. If you haven’t used it yourself, I highly recommend you check it out - it WILL make you a better Python coder.(Thanks to Matt Stone for introducing me!) This particular error is common if you forget to append a newline character to the end of your python script, but I was getting one for every single line of code in my program.

The Evolution of Network Programmability

This post is the “text” version of a talk I gave at Cisco Live US 2014 titled “SDN: People, Process, and Evolution”. While there is certainly some technical details involved here, this topic is really more of a philosophical one, and it is very near and dear to my heart as I talk with more folks about how networking is going to evolve in the years to come. The Problem with Networking Most of my readers would consider themselves network engineers - folks that live and breathe networking and everything that’s required to build them.

Pylint Errors – Final Newline Missing

I recently ran into a slew of errors when using Pylint - a sort of “quality checker” for your Python code. If you haven’t used it yourself, I highly recommend you check it out - it WILL make you a better Python coder.(Thanks to Matt Stone for introducing me!) This particular error is common if you forget to append a newline character to the end of your python script, but I was getting one for every single line of code in my program.

Open vSwitch 201 & 301

[Special and huge thanks to Scott Lowe for answering an endless amount of questions I had while writing this post and testing with NSX/OVS over the last few days. Thanks to Deepesh as well who I bounced OVS questions off of when I needed to give Scott a break. ]

In Open vSwitch 101, I described the three main components that make up Open vSwitch (OVS) from an architectural standpoint, namely ovs-vswitchd, ovsdb-server, and the fast path kernel module.  If you start to work with OVS, the first thing you realize is that it takes quite a bit more knowledge to really understand it.  This post will focus on some design principles and options when running OVS on a hypervisor like KVM in conjunction with a network virtualization solution.
To make this a little more practical, we will use a scenario which consists of a KVM host with 3 physical NICs – 1 x 1G and 2 x 10G.  The 1G interface will be used for management and the 2 x 10G interfaces will be used for actual transport of VM traffic. 

This example will also assume the use of an overlay network virtualization solution Continue reading

News Roundup: Embrane, Cisco Prime NCS, F5 and VMware

Cisco Live happened in the US this week and it seems like a good time to briefly summarise a few of the anouncements that I saw. Embrane Pivots Embrane announced that they will be offering: …. lifecycle management for virtual network service delivered within Cisco ACI™. The company also announced plans for integrating the Embrane […]

The post News Roundup: Embrane, Cisco Prime NCS, F5 and VMware appeared first on EtherealMind.

BGP dampening – punishment for unstable BGP prefixes

How does the internet work - We know what is networking

BGP prefix flapping can be caused by different issues in network. Basically every unstable network where links are unreliably and are going up and down here and there can cause BGP prefix flapping. Every prefix flap will cause some networks to became unreachable. BGP process will then need to recalculate best-path in order to hopefully […]

BGP dampening – punishment for unstable BGP prefixes

Welcome to the IP address Lookup tutorial

A router’s main function is to forward an incoming packet to its destination by using routing and forwarding techniques. Forwarding can be defined as taking the incoming packet, looking at its destination IP address, consulting the forwarding table, and directing the packet to the appropriate next-hop and output link based on the information retrieved from the forwarding table. On the other hand, routing is the process by which the forwarding table itself is built. Forwarding is a relatively simple process performed locally at the router, whereas routing depends on a variety of distributed dynamic and static routing protocols.

To consult the forwarding table, the router uses the packet’s destination IP address as a key to retrieve the forwarding information (e.g., next-hop and output interface) – this operation is called IP address lookup. Once the forwarding information is available, the router transfer the packet from the incoming interface to the appropriate outgoing interface.

The greatest challenge and major bottleneck is how to make the IP address lookup fast enough to keep up with backbone routers that support high data rate interfaces (up to 10 Gbps and more). Therefore, they must be able to perform millions of address lookup operations Continue reading

A Short Update on CML from #CLUS

Hey everyone,

I’ve been having a really good time here at Cisco Live US. Here is a short update on CML.

General Info

CML is being released end of June or beginning of July. The corporate edition with
a base license and support for up to 15 nodes will be listed at around 13000$ per year.
If you subscribe for two years, the discount is 5% and for three years it is 10%
Normally 15 nodes cost around 13000$ per year so basically you get 5 nodes for “free”
if you get the base package which has the SKU R-CML-CE-K9=.
IOS will be supported by running IOSv. Every IOSv image requires around 512 MB of memory.

System Requirements:

  • The Cisco Modeling Labs server runs on VMware ESXi 5.0, 5.1, and 5.5.
  • Recommended – Cisco UCS®
  • C220 M3 Rack Server with 16 core CPU and 128 GB memory or Cisco UCS
  • C460 M2 High-Performance Rack Server or higher model (actual memory and CPU consumption depends
    on the number of virtual nodes and virtual network OS types). To help determine the appropriate memory
    please find the Cisco Modeling Labs Calculator at http://www.cisco.com/go/cml.
  • Following are the minimum hardware Continue reading

Renesys, Dyn Join Forces

Today, we’re announcing the acquisition of Renesys by Dyn, the leading provider of Internet Performance solutions. Dyn and Renesys represent the perfect combination of Internet Intelligence assets from Renesys and Traffic Management and Message Management solutions from Dyn. We’re excited to become part of the Dyn team!

Those who know both companies may ask, “What took you so long?” Our headquarters are located blocks apart in beautiful downtown Manchester, New Hampshire, and the two founding teams have known each other for years. Dyn and Renesys share a surprising amount of cultural DNA – building scalable global infrastructure, understanding the economics and performance of the Internet at a deep technical level, and helping our customers deliver smarter, faster service worldwide.

Why Renesys? Why Dyn?

Renesys builds network performance management products for the Internet. We help enterprises tackle the strategic and operational challenges of delivering service over the public Internet, to consumers and businesses beyond the firewall. We operate a best-in-breed global Internet measurement platform, performing over a billion measurements each day to assess the Internet’s health and function. Anywhere in the world, when a decision maker needs insight into local Internet infrastructure, performance impairment, economics, competition, or strategy, we Continue reading

NFV: Will vRouters ever replace hardware routers?


When i started looking at NFV, i always imagined it being relegated to places in the network that would receive only teeny weeny amount of data traffic since the commodity hardware and software could only handle so much of traffic. I also naively believed that it would be deployed in networks where customers were not uber-sensitive to latency and delay (broadband customers, etc). So if somebody really wanted a loud bang for their buck they had to use specialized hardware to support the network function. You couldnt really use Intel x86-based servers running SW serving customers for whom QoS and QoE were critical and vital. The two examples that leap to my mind are (i) Evolved Packet Core (EPC) functions such as Mobility Management Entity (MME) and BNG environments where the users need to be authorized before they can expect to receive any meaningful services.

While i understood that servers were getting powerful and Intel was doing its bit with its Data Plane Development Kit (DPDK) architecture, it didnt occur to me till recently that we would be seeing servers handling traffic at 10G+ line rate. Vyatta, a Brocade company now, uses vRouters to implement real network functions. Vyatta started with its modest 5400 vRouter that could Continue reading

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