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Internetworking perspectives by Ivan Pepelnjak
Updated: 2 hours 38 min ago

Building a Small Cloud with UCS Mini

19 hours 28 min ago

During the last round of polishing of my Designing Infrastructure for Private Clouds Interop New York session (also available in webinar format) I wondered whether one could use the recently-launched UCS Mini to build my sample private cloud.

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It’s the Application Development, Stupid

September 28, 2014 - 6:12am

I love reading blog posts on Plexxi blog (you SHOULD add them to your RSS reader) and the “It’s the Application, Stupid” series from Mat Matthews is no exception. What pleasantly surprised me was that a large enterprise came to the same conclusions I’m preaching for the last few years.

TCP Is a Stream Protocol

September 26, 2014 - 10:15pm

I hope you know TCP provides a reliable stream service not reliable packet delivery, but you might not have realized all the implications – I found an old post by Robert Graham explaining how things really work and how you can use them to bypass quick-and-dirty IDS that rely on signatures instead of doing proper protocol decodes.

Schprokits with Jeremy Schulman on Software Gone Wild

September 25, 2014 - 10:19pm

Jeremy Schulman was the driving force behind the Puppet agent that Juniper implemented on some Junos switches (one of the first fully supported Puppet-on-a-switch implementations). In the meantime, he quit Juniper and started his own company focused on a network automation product – more than enough reasons to chat with him on Software Gone Wild.

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Quick Guide to my Interop New York Sessions

September 24, 2014 - 10:34pm

I’m running or participating in five workshops or sessions during next week’s Interop New York. Three of them build on each other, so you might want to attend all of them in sequence:

Designing Infrastructure for Private Clouds starts with requirements gathering phase and focuses on physical infrastructure design decisions covering compute, storage, physical and virtual networking, and network services. If you plan to build a private (or a reasonable small public) cloud, start here.

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Network Programmability 101: The Problem

September 23, 2014 - 10:57pm

In the first part of the Network Programmability webinar Matt Oswalt described some of the major challenges most networks are facing today:

  • Why is everyone claiming that the network is so slow to change?
  • Is that really the case? Why?
  • Why is the manual configuration culture so widespread in networking?
  • How does the holistic thinking in the design phase dissolve into the box mentality of CLI commands?
  • How does the box mentality limit the scalability of network deployments?
Enjoy the video recording

Connecting Virtual Routers to the Outside World

September 22, 2014 - 10:32pm

Stefan de Kooter (@sdktr) sent me a follow-up question to my Going All Virtual with Virtual WAN Edge Routers blog post:

How would one interface with external Internet in this scenario? I totally get the virtual network assets mantra, but even a virtual BGP router would need to get a physical interconnect one way or another.

As always, there are plenty of solutions depending on your security needs.

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SDN Deployment Considerations

September 22, 2014 - 5:15am

Are you lucky enough to be one of the 87% of North American enterprises that plan to have SDN in production by 2016 or one of the 53% of the companies that plan to have SDN deployed in the near future? Even though we all know how inflated these claims are, you might have to start considering the deployment aspects of a solution a $vendor will persuade your CIO to buy.

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Formal Announcement: Software Gone Wild Podcast

September 21, 2014 - 10:12pm

If you’ve been reading my blog in the last few months, you might have noticed that I started a new podcast focused on software-defined everything (hence the name: Software Gone Wild – thanks to Jason Edelman).

The latest episodes are always available on this page; you can also subscribe to the podcast feed in RSS, Atom or iTunes format… and if you wonder why we need yet-another podcast, read the About Software Gone Wild document.

Virtual Networking in CloudStack

September 19, 2014 - 3:39am

If you mention open-source cloud orchestration tools these days, everyone immediately thinks about OpenStack (including the people who spent months or years trying to make it ready for production use). In the meantime, there are at least two other comparable open-source products (CloudStack and Eucalyptus) that nobody talks about. Obviously having a working product is not as sexy as having 50+ vendors and analysts producing press releases.

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Dynamic FCoE – Sparse-Mode FCoE Strikes Again

September 17, 2014 - 10:47pm

A while ago Cisco added dynamic FCoE support to Nexus 5000 switches. It sounded interesting and I wanted to talk about it in my Data Center Fabrics update session, but I couldn’t find any documentation at that time.

In the meantime, the Configuring Dynamic FCoE Using FabricPath configuration guide appeared on Cisco’s web site and J Metz wrote a lengthly blog post explaining how it all works, triggering a severe attack of déjà vu.

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You’ve been doing the same thing for the last 20 years

September 17, 2014 - 12:06am

When we were discussing my autumn travel plans, my lovely wife asked me “What are you going to talk about in Bern?” She has a technical background, but I didn’t feel like going into the intricacies of SDN, SDDC and NetOps, so I told her the essence of my keynote speech:

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The Four Paths to SDN

September 16, 2014 - 10:57am

After the initial onslaught of SDN washing, four distinct approaches to SDN have started to emerge, from centralized control plane architectures to smart reuse of existing protocols.

As always, each approach has its benefits and drawbacks, and there’s no universally best solution. You just got four more (somewhat immature) tools in your toolbox. And now for the details.

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SIGS & Carrier’s Lunch DC Day: An Event Definitely worth Visiting

September 14, 2014 - 10:12pm

I spent last Tuesday in Bern attending the SIGS DC Day Event, and came back home extremely pleasantly surprised. The conference was nice and cozy, giving everyone plenty of opportunities to chat about data center technical challenges (thanks for all the wonderful conversations we had – you know who you are!).

Having the opportunity to meet fellow networking engineers and compare notes is great, but it’s even better to combine that with new knowledge, and that’s where the event really excelled.

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Tech Talks: The Essence of MPLS

September 11, 2014 - 10:59pm

Seamus Gilchrist sent me a fantastic list of MPLS- and MPLS-TE-related questions. Instead of starting an email exchange we agreed on something that should benefit a wider community: a lengthy whiteboard session discussing the basics of MPLS, MPLS-TE, load balancing and QoS in MPLS networks…

The first part of our conversation is already online: The Essence of MPLS.

Watch the video

Open-Source Hybrid Cloud Reference Architecture on Software Gone Wild

September 10, 2014 - 10:19pm

A while ago Rick Parker told me about his amazing project: he started a meetup group that will build a reference private/hybrid cloud heavily relying on virtualized network services, and publish all documentation related to their effort, from high-level architecture to device and software configurations, and wiring plans.

In Episode 8 of Software Gone Wild Rick told us more about his project, and we simply couldn’t avoid a long list of topics including:

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IPv6 Neighbor Discovery (ND) and Multicast Listener Discovery (MLD) Challenges

September 10, 2014 - 10:13am

A few days ago Garrett Wollman published his exasperating experience running IPv6 on large L2 subnets with Juniper Ex4200 switches, concluding that “… much in IPv6 design and implementation has been botched by protocol designers and vendors …” (some of us would forcefully agree) making IPv6 “…simply unsafe to run on a production network…

The resulting debate on Hacker News is quite interesting (and Andrew Yourtchenko is trying hard to keep it close to facts) and definitely worth reading… but is ND/MLD really as broken as some people claim it is?

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vMotion Enhancements in vSphere 6

September 8, 2014 - 10:40pm

VMware announced several vMotion enhancements in vSphere 6, ranging from “finally” to “interesting”.

vMotion across virtual switches. Finally. The tricks you had to use previous were absolutely bizarre.

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Controller Cluster Is a Single Failure Domain

September 8, 2014 - 9:19am

Some OpenFlow-focused startups are desperately trying to tell you how redundant their architecture is. Unfortunately all the whitepapers (and the prancing unicorns) cannot change a simple fact: an SDN controller (OpenFlow-based or otherwise) is in some aspects a single failure domain.

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Is Anyone Using DMVPN-over-IPv6?

September 7, 2014 - 9:10am

One of my readers sent me an interesting challenge: they’re deploying a new DMVPN WAN, and as they cannot expect all locations to have native (non-NAT) IPv4 access, they plan to build the new DMVPN over IPv6. He was wondering whether it would work.

Apart from “you’re definitely going in the right direction” all I could tell him was “looking at the documentation I couldn’t see why it wouldn’t work” Has anyone deployed DMVPN over IPv6 in a production network? Any hiccups? Please share your experience in the comments. Thank you!