Forming a Thought Process for Troubleshooting

Periodically, I get a message from someone asking for troubleshooting help. The most recent of these went something like the following (paraphrasing)–

I have the following routers, R1 through R5, and I cannot ping R5 from R1. Please tell me what the problem is.

In these cases, I could review the configuration or import them into my lab. Inevitably, that might solve the problem for the individual. However, it doesn’t really help the individual solve problems in the future. I prefer to try to help others think through the problem and reach the solution on their own.

Given the symptom of R1 not being able to ping R5, what could that mean? My initial thoughts are–

1. R1 isn’t producing packets destined to R5
2. R5 isn’t producing packets destined to R1
3. One of the routers between R1 and R5 doesn’t know how to reach R5
4. One of the routers between R5 and R1 doesn’t know how to reach R1
5. Traffic is being filtered somewhere along the way

The first step in troubleshooting this is to understand that there should be two flows being produced. The first flow is a series of echo requests from R1 to R5 and the other flow is a Continue reading

Secret Sunday: Microsoft’s Raymond Chen

Taking a little side-step from the normal networking-based Sunday hero worship, today’s Secret Sunday is a pointer to Microsoft’s Raymond Chen, sometimes referred to as “Microsoft’s Chuck Norris“. But John, you say, it’s Microsoft; why would you do that to … Continue reading →

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How the CCIE changed my life

Everything is so gloomy these days isn’t it? SDN is going to put us out of a job so you have to learn Python or go make burgers (been there done that). The CCIE is now irrelevant so why would anyone pursue it? While there are some good arguments for its demise there are also […]

Author information

Keith Humphreys

Keith is a network architect and CCIE #40869 working as a consultant. His main focus is on IP/MPLS design and he is a big fan of Alcatel-Lucent SR-OS. Follow him on Twitter and check out his blog over at iamjeffvader.com

The post How the CCIE changed my life appeared first on Packet Pushers Podcast and was written by Keith Humphreys.

Provision supports Portal Redirect for BYOD use

Keep an Open Mind

We all know that IT changes rapidly, but we still don’t always accept what that means. Companies and technologies change over time, and good engineers recognise this. Poor engineers cling to past beliefs, refusing to accept change. Try to keep an open mind, and periodically re-evaluate your opinions.

Consider the Linux vs Microsoft debate. I’ve been an Open Source fan for a long time, and have plenty of experience running Linux on servers and desktops. Today I use OS X as my primary desktop. I’ve cursed at Microsoft many times over the years, usually when dealing with some crash, security issue, or odd design choice.

But it annoys the hell out of me when I hear engineers spouting tired old lines about Microsoft products crashing, or having poor security. This is usually accompanied by some smug look “Hur hur hur…Microsoft crash…Blue Screen of Death…hur hur hur”

I get frustrated because these people aren’t paying attention to what Microsoft has been doing. They have come a very long way since the 2002 Bill Gates email setting security as the top priority. It’s a big ship to turn, and it took time. Their overall security model and practices are far better than they were, Continue reading

Provision support for IRF MAD LACP Split brain detection

Anachronism In the UK (and elsewhere)

I’m a long way from being the first person to comment that some of the icons we use in our software are somewhat anachronistic. The example we hear most often is that of the Save icon in most software: It … Continue reading →

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Response: Midokura Open-Sources MidoNet

Last week Midokura decided to follow Juniper’s lead and make MidoNet an open-source product (after all, a similar move worked really well for Contrail, right?).

I may be too skeptical (again), but I fail to see how this could possibly work.

CORE Network Emulator Services overview

CORE Services is a feature of the CORE Network Emulator — an open-source network simulator — that configures and starts processes on each node running in a network simulation. Examples of processes supported by CORE Services are: quagga, dhcpd, or radvd.

Because the CORE Network Emulator implements its virtual nodes using a lightweight virtualization technology called Linux namespaces, we cannot use the normal init or upstart scripts to start networking daemons on these nodes. We must use CORE Services.

A benefit of using CORE Services is that they allow us to set up and manage processes running on each node by using the CORE GUI. This may reduce the time required to configure nodes used in a simulation scenario, especially if a large number of nodes require similar configuration procedures. Also, network scenarios that require customized configurations can be saved and used again if those configurations are implemented by customizing CORE Services.

To run complex network simulation scenarios, we must understand how to use CORE Services. In this post we will provide an overview of CORE Services.

Overview

CORE Services are used to start processes on the virtual nodes in a CORE network simulation. For the processes Continue reading

PlexxiPulse—Conversations on the SDN “Technique Churn”

Ethan Banks (@ecbanks) initiated an interesting Twitter conversation last weekend by claiming that the constant “technique churn” within organizations that utilize SDN and NetOps is doing the networking industry a disservice. Banks feels that ever-changing frameworks make it nearly impossible to thoroughly understand new technologies. Our own Mike Bushong (@mbushong) took a deep dive into the subject on the Plexxi blog this week in response to those claims. Be sure to check it out before you head out for the day.

In this week’s PlexxiTube video of the week, Dan Backman explains how Plexxi’s Big Data fabric solution can run both L2 and L3 simultaneously.

SDN Users’ Wish Lists Sounds a Lot Like White Box Switching

In an article this week for SDN Central, Craig Matsumoto looks at users that are growing increasingly tired of vendor lock-in and therefore turn to white box switching to provide additional interoperability. In my opinion, the interoperability provided is interesting as it is not a property of vendor intentions. When we accelerate the pace of innovation, there are going to be new capabilities that get added to gear. At the time of first-add, no one else supports the feature. At Continue reading

Storage Traffic Magic with OpenFlow

I am in the Bay Area this week, working on some network automation stuff, and I was fortunate to be able to stop by and say hello to the Storage Field Day 6 folks over drinks.

I was told by several impressed delegates about a talk by Andy Warfield of Coho Data, where he described how they used OpenFlow to steer storage traffic intelligently to and from various nodes in a distributed storage array.

For the majority of the discussion, he talks at length about how NICs have long been able to push more data than a single CPU core is able to process, and as a result, they have to be intelligent about the distribution of packet processing onto the cores within a multicore system.

In summary, a big problem with file-based storage systems is dealing with load sharing. NFS clients have to point to an IP address where the exports are located, and if this IP address was available only on a single NIC on a storage array, this pretty severely limits your options – that port becomes a big bottleneck. I’ve seen some customers assign IP addresses to several ports on an array, and use them in rotations Continue reading

Rewarding Effort vs Results

Sometimes we confuse effort with outcome. We think that hours spent are more important than outcomes achieved. Or we unintentionally create a system where effort is rewarded, rather than outcomes.

Consider a situation where you work for a consulting firm, doing capped Time & Materials jobs. The client gets charged for the amount of time actually worked. Any amount of time up to the cap will be accepted. If more time is needed to complete a task, you’ll need to go back to the client to negotiate for more time/money. Occasionally you’ll need to do that, but usually the job will be completed under the cap.

As a consultant, you’re normally measured on your utilisation, and the amount you bill. So what’s the optimum amount of work to do for each job? Funnily enough, it is very close to the amount estimated – no matter what the estimate was. Maximise revenue & utilisation, while still doing the work under budget. There’s no incentive to do the job quicker.

Look at it from the perspective of two different consultants, Alice & Bob:

• Alice is a diligent worker, who gets through her work as quickly as possible. Repeatable tasks are scripted. She doesn’t muck around.
• Bob is a Continue reading

Network Break 19 – Fixed

Note: We had an audio problem and Network Break 19 is now fixed.

Author information

Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at EtherealMind.com and on Twitter @etherealmind and Google Plus.

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The post Network Break 19 – Fixed appeared first on Packet Pushers Podcast and was written by Greg Ferro.

Technology Short Take #46

Welcome to Technology Short Take #46. That’s right, it’s time for yet another collection of links and articles from around the Internet on various data center-related technologies, products, projects, and efforts. As always, there is no rhyme or reason to my collection; this is just a glimpse into what I’ve seen over the past few weeks. I hope you are able to glean something useful.

Networking

• This post by Matt Oswalt—the first in a series, apparently—provides a great introduction to 5 development tools for network engineers. I’ve already increased my usage of Git in an effort to become more fluent with this very popular version control tool, and I was already planning on exploring Jinja2 as well (these are both mentioned in Matt’s article). This is a really useful post and I’m looking forward to future posts in this series.
• Matt also recently posted part 4 (of 5) in his series on SDN protocols; this post covers OpFlex and declarative networking.
• It was good to read this post on Cumulus Linux first impressions by Jeremy Stretch. I’m a fan of Cumulus, but I’m admittedly a Linux guy (see here) so you might say I’m a bit biased. Jeremy is Continue reading

SDN And More – Interop Roundtable Discussion

This September I was invited to come to New York for Interop New York 2014 and participate in a couple of technical sessions as part of a Tech Field Day Extra event. In addition to the presentations by HP Networking and … Continue reading →

If you liked this post, please do click through to the source at SDN And More – Interop Roundtable Discussion and give me a share/like. Thank you!

Technology Short Take #46

Welcome to Technology Short Take #46. That’s right, it’s time for yet another collection of links and articles from around the Internet on various data center-related technologies, products, projects, and efforts. As always, there is no rhyme or reason to my collection; this is just a glimpse into what I’ve seen over the past few weeks. I hope you are able to glean something useful.

Networking

• This post by Matt Oswalt—the first in a series, apparently—provides a great introduction to 5 development tools for network engineers. I’ve already increased my usage of Git in an effort to become more fluent with this very popular version control tool, and I was already planning on exploring Jinja2 as well (these are both mentioned in Matt’s article). This is a really useful post and I’m looking forward to future posts in this series.
• Matt also recently posted part 4 (of 5) in his series on SDN protocols; this post covers OpFlex and declarative networking.
• It was good to read this post on Cumulus Linux first impressions by Jeremy Stretch. I’m a fan of Cumulus, but I’m admittedly a Linux guy (see here) so you might say I’m a bit biased. Jeremy is Continue reading

The Unofficial JNCIE-ENT Prep Guide

Some of you may have heard that Jeff Fry has published his Unofficial JNCIE-ENT Prep Guide, but how many of you have purchased it yet? I’ve had the opportunity to look it over as he was completing it, and I must say it is an impressive collection of work. He has stuffed over 500 pages into the workbook and we’re not talking about fluff. Countless hours and many months of work later, he has published it with LeanPub, and will continue to issue updates. That is one of the nice things about Leanpub, with your purchase, you have the right to receive all future updates to the content! And many publishers, at least the ones I’ve purchased from, do push out significant updates to their work. You also receive a 100% guarantee on your purchase, that means if you are not happy, you can receive a full refund within 45 days of purchase. Jeff has also published a sample which includes the full table of contents and small sample section of the content.

If you’re studying for the JNCIE-ENT use the link below and receive 25% off your purchase.

The post The Unofficial JNCIE-ENT Prep Guide appeared first on Continue reading

7-Nov-2014: Press Releases From Meru, Gigamon, Big Switch + Dell

Imtech’s SDN and NFV demo

This is a pretty cool demo of SDN (Software-Defined Networking) and NFV (Network Function Virtualization) by our SDN Consultant.  I’ve seen a lot of slideware on Contrail and NFV, but they don’t really help understanding very well.  Seeing it actually happen makes a world of difference.

Watch the demo trailer here.

FlipIT Cloud: Orchestrating IT-as-a-Service on Software Gone Wild

Imagine being an IT administrator running a multi-tenant enterprise environment (example: an SMB business center). How many things would you have to configure to add a new tenant? How about adding a new user for an existing tenant?

The engineers behind the scenes of FlipIT cloud service ended up with a 40-page configuration guide when they started the service years ago… and obviously decided full-blown automation is the only way to go.