We Need to Move from Assembling Car Parts to Driving Cars

During a great conversation I had with Terry Slattery during Interop New York, he said “well, I don’t think anyone should be configuring VLANs and asking ÔÇśHow to configure a VLAN on a switch’ – we should be focused on providing end-to-end connectivity”, and there’s absolutely nothing in that statement that one could disagree with.

From VIRL to IOU and Back

EIGRP SIA (Stuck-In-Active) through animations.

EIGRP SIA (Stuck-In-Active) through animations.

Networking Field Day 9 First look: Generation-SDN -Part 1

New CCIE RSv5 Workbook Troubleshooting & Full Scale Labs Posted

Troubleshooting Lab 3 and Full Scale Lab 3 have now been added to the CCIE RSv5 Workbook!

The new Troubleshooting Lab 3 uses the Full Scale Lab 1 logical topology, but breaks all of the protocols you’ve previously built. I suggest you take your time with each ticket so that you can fully digest why each fault occurs. Practice your time and knowledge skills by taking the Troubleshooting Lab 3 challenge!

Full Scale Lab 3 is built on a brand new logical topology, and has a strong focus in MPLS and BGP technologies. The solution guide features detailed breakdowns of each topic domain to give you a better understanding of the solutions used to solve each task. Keep in mind that there are multiple ways to solve most problems.

For discussion on these new labs visit our online community, IEOC.

Enjoy!

Cisco offers ACI alternative for Nexus 9000 switches

Cisco is adding a new control plane capability to its Nexus 9000 switches for customers not yet opting for or needing a full-blown application policy infrastructure.Cisco’s BGP Control Plane for VXLAN is designed to appeal to operators of multitenant clouds looking for familiar BGP routing protocol features with which to scale their networks and make them more flexible for the demands of cloud networking. VXLAN, which scales VLAN segmentation to 16 million endpoints, does not specify a control plane and relies on a flood-and-learn mechanism for host and endpoint discovery, which can limit scalability, Cisco says.To read this article in full or to leave a comment, please click here

Path MTU discovery in practice

Last week, a very small number of our users who are using IP tunnels (primarily tunneling IPv6 over IPv4) were unable to access our services because a networking change broke "path MTU discovery" on our servers. In this article, I'll explain what path MTU discovery is, how we broke it, how we fixed it and the open source code we used.

First there was the fragmentation

When a host on the Internet wants to send some data, it must know how to divide the data into packets. And in particular it needs to know the maximum size of packet. The maximum size of a packet a host can send is called Maximum Transmission Unit: MTU.

The longer the MTU, the better for performance, but the worse for reliability, because a lost packet means more data to be retransmitted and because many routers on the Internet can't deliver very long packets.

The fathers of the Internet assumed that this problem would be solved at the IP layer with IP fragmentation. Unfortunately IP fragmentation has serious disadvantages and it's avoided in practice.

Do-not-fragment bit

To work around fragmentation problems the IP layer contains a "Don't Fragment" bit on every IP packet. Continue reading

A Baker’s Dozen, 2014 Edition

As is our annual tradition, this blog provides a year-end review of how the Internet providers at the top of our IP Transit Intelligence global rankings (formerly, Renesys’ Market Intelligence) fared over the previous year.  The structure and performance of the Internet remains a huge blind spot for most enterprises, even those critically dependent on it for business operations.  Whether it’s the next 3 billion people coming online, poor performance due to suboptimal routing, or security breaches of a trust-based Internet infrastructure, Dyn provides critical insight into the structure and performance of the Internet, both real-time and historical, via its Internet Intelligence products.  More importantly, our services help our customers make the changes necessary to optimize Internet availability, reliability, and reach.  This blog reviews a single very small slice of our data related to the sizes of the top global players as it pertains to the markets and customers they serve.

Back in 2008, we chose to look at the 13 providers that spent at least some time in the Top Ten that year, hence the name “Baker’s Dozen“.  We repeated that exercise in 2009, 2010, 2011, Continue reading

From VIRL to IOU and Back

From VIRL to IOU and Back

From VIRL to IOU and Back

Data-Driven RESTful API Testing for Java

This post is a Zombie that I'm resurrecting from my drafts. I"m not doing any Java these days, but hopefully this post might be useful to somebody

In my quest to get better code coverage for the OVSDB project in OpenDaylight I started to look at increasing coverage for the REST API. It's pretty difficult to test this in an efficient way (lines of code) and frameworks like Robot would have been easier to use. The disadvantage with using an external test framework is that code coverage (using a plugin like JaCoCo) would not be logged. Therefore I harnessed my Junit-Jitsu and found a solution that lives in the JVM

The Scenario

Lets take a very simple example REST API

GET, PUT: /v2/foo

Step 1: The Solution Components

The solution uses the following components

• JUnit Parameterized Test Runner
• YAML
• Jersey Client

The parameterized runner will run run a test multiple times given a bunch of parameters. This way we can write one test, specifiy our parameters in YAML and let JUnit do the hard work!

Step 2: Writing the YAML file

Here's a sample YAML file:

---
- name: testGetAllFoo
  operation: GET
  uri Continue reading

Data-Driven RESTful API Testing for Java

This post is a Zombie that I'm resurrecting from my drafts. I"m not doing any Java these days, but hopefully this post might be useful to somebody

In my quest to get better code coverage for the OVSDB project in OpenDaylight I started to look at increasing coverage for the REST API. It's pretty difficult to test this in an efficient way (lines of code) and frameworks like Robot would have been easier to use. The disadvantage with using an external test framework is that code coverage (using a plugin like JaCoCo) would not be logged. Therefore I harnessed my Junit-Jitsu and found a solution that lives in the JVM

Combining MPLS/VPN, MPLS-TE and QoS on MPLS Talks

In the final part of our MPLS-focused discussion, Seamus wanted to know how one could combine MPLS/VPN, MPLS-TE and QoS (for example, sending VoIP traffic for one customer over a different path).

Short answer: don’t even think about doing that. The added complexity is not worth whatever extra money you’ll be charging the customer (or not).

From VIRL to IOU and Back

Networking Field Day 9: First look- Monitor the network with NetBeez?!

Data-Driven RESTful API Testing for Java

This post is a Zombie that I'm resurrecting from my drafts. I"m not doing any Java these days, but hopefully this post might be useful to somebody

In my quest to get better code coverage for the OVSDB project in OpenDaylight I started to look at increasing coverage for the REST API. It's pretty difficult to test this in an efficient way (lines of code) and frameworks like Robot would have been easier to use. The disadvantage with using an external test framework is that code coverage (using a plugin like JaCoCo) would not be logged. Therefore I harnessed my Junit-Jitsu and found a solution that lives in the JVM

Cisco MDS Port-Security with Auto-Learning

Why Network Engineering Is a Top Job for 2015

According to career marketplace Glassdoor, one of the top 25 best jobs in America for 2015 is “network engineer.” No surprises here. Network engineering is a high growth industry: interesting and challenging work, tons of autonomy in how to solve problems and come up with solutions, well paying, and most importantly, the knowledge that you’re building something and bringing creations to life.   

Indeed, the complexities of modern networks make network engineers indispensable, with the mix of virtual and real servers, cloud services and data centers, and of course, the integration of SDN into your network. On a good day, you get that rush of power from doing what is essentially mad science. 

It should be noted that network engineering was one of eight IT-based jobs to crack the top 25. Clearly, technical skills are in demand. 

You know, it brings me back to Nicholas Carr’s books “Does IT Matter?” and “The Big Switch,” which expanded on a 2003 article he wrote in Harvard Business Review claiming that “IT Doesn’t Matter.” Essentially, Carr predicted Continue reading