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Internetworking perspectives by Ivan Pepelnjak
Updated: 3 hours 6 min ago

Puppet Is a Tool, DevOps Is a Lifestyle

April 15, 2014 - 10:20pm

During Interop 2014 I got involved in numerous interesting conversations revolving around SDN and new operations models (including the heretic idea of bundling appliances with application stacks and making developers responsible for network services).

During one of those discussions someone said “I think I get the ideas behind DevOps, but I don’t think we should configure our network devices with Puppet or Chef” to which I replied “Puppet or Chef are just tools, DevOps is a lifestyle.

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IS-IS in Avaya’s SPB Fabric: One Protocol to Bind Them All

April 14, 2014 - 11:45pm

Paul Unbehagen made an interesting claim when presenting Avaya network built for Sochi Olympics during a recent Tech Field Day event: “we didn’t need MPLS or BGP to implement L2- and L3VPN. It was all done with SPB and IS-IS.”

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Troubleshooting Residential IPv6 Connectivity

April 13, 2014 - 10:18pm

Most ISPs rolling out large-scale residential IPv6 (bringing US to ~7%, Switzerland to ~10% and Belgium above 16%) agree it’s a no-brainer, but the rest of the world still hesitates.

To help the dubious majority cross the (perceived) shaky bridge across the gaping chasm between IPv4 and IPv6, a team of great engineers with decades of IPv6 operational experience (including networking gurus from Time Warner, Comcast and Yahoo, and the never-tiring IPv6 evangelist Jan Žorž) wrote an IPv6 Troubleshooting for Helpdesks document.

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Network Function Virtualization (NFV) 101

April 10, 2014 - 10:32pm

When I first heard about NFV, I thought it was just another steaming pile of hype designed to push the appliance vendors to offer their solutions in VM format. After all, we’re past the hard technical challenges: most appliances deserve to have an Intel Inside sticker, performance problems have been addressed (see Intel DPDK, 6WIND, PF_ring and Snabb Switch), so what’s stopping us from deploying NFV apart from stubborn vendors who want to sell hardware, not licenses?

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Changes in IBGP Next Hop Processing Drastically Improve BGP-based DMVPN Designs

April 9, 2014 - 9:46pm

I always recommended EBGP-based designs for DMVPN networks due to the significant complexity of running IBGP without an underlying IGP. The neighbor next-hop-self all feature introduced in recent Cisco IOS releases has totally changed my perspective – it makes IBGP-over-DMVPN the best design option unless you want to use DMVPN network as a backup for MPLS/VPN network.

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Three Common Mistakes That Can Doom Your Private Cloud

April 8, 2014 - 11:41pm

In the first half hour of the Infrastructure for Private Clouds workshop at last week’s Interop Las Vegas I focused on business aspects of private cloud design: defining the customers, the services, and the level of self-service you’ll offer to your customers.

Nick Martin published a great summary of these topics @ SearchServerVirtualization; I couldn’t have done it better myself (they want to get your email address, but this article is definitely worth it).

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Should We Use Redundant Supervisors?

April 7, 2014 - 10:19pm

I had a nice chat with Doug Gourlay from Arista during the Interop Las Vegas and he made an interesting remark along the lines of “in leaf-and-spine fabrics it doesn’t make sense to use redundant supervisors in switches – they cause more problems than they solve.”

As always, in the end it all depends on your environment and use case, but he definitely has a point; good engineering always works better than a heap of kludges.

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Real Life BGP Route Origination and BGP Next Hop Intricacies

April 6, 2014 - 10:21pm

During one of the ExpertExpress engagements I helped a company implement the BGP Everywhere concept, significantly simplifying their routing by replacing unstable route redistribution between BGP and IGP with a single BGP domain running across MPLS/VPN and DMVPN networks.

They had a pretty simple core site network, so we decided to establish an IBGP session between DMVPH hub router and MPLS/VPN CE router (managed by the SP).

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Video: VMware NSX Architecture

April 4, 2014 - 5:52am

Not sure I published a link to this video: the overview of VMware NSX Architecture (for additional details watch other videos from the VMware NSX Architecture webinar).

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The Hierarchy of Isolation

April 3, 2014 - 6:30am

Friday roundtables are one of the best parts of the Troopers conference – this year we were busy discussing (among other things) how safe the hypervisors are as compared to more traditional network isolation paradigms.

TL&DR summary: If someone manages to break into your virtualized infrastructure, he’ll probably find easier ways to hop around than hypervisor exploits.

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Security and SDN

April 2, 2014 - 6:30am

I don’t think it would be too hard to guess the topic of my talk at the recent Troopers conference: SDN was the obvious choice, and the presentation simply had to include security aspects of SDN.

TL&DR summary: We know how to do it. We also know it's not simple.

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Quantum SDN

April 1, 2014 - 6:01am

An interesting startup is launching their SDN solution @ Interop Las Vegas today: Quantum Networks use the latest quantum computing technology to solve some of the hardest problems of controller-based networking.

One of the fundamental problems of hardware-based OpenFlow solutions is the flow update rate – most switches using merchant silicon can insert around 1000 new flows per second into their forwarding tables. Technologies based on quantum mechanics effects change all that – a quantum entanglement technology patented by Quantum Networks can install new flows instantaneously across the whole network.

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STP in Brocade VCS Fabric – an Interesting Solution after a Long Wait

March 31, 2014 - 6:31am

A few years ago I lambasted the lack of STP support in Brocade’s VCS fabric. It took Brocade over two years to solve the problem, but they finally came up with an interesting end-to-end solution.

Here are a few highlights; for more details read the Configuring STP-type Protocols section in Network OS Administrator Guide.

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IPv6-Only Data Center Deployment

March 28, 2014 - 12:19am

Last June Tore Anderson talked about his IPv6-only data center deployment (the idea made very popular recently after Facebook’s presentation @ V6 World Congress) in one of my free webinars. In case you missed the videos explaining the technical details, watch them or view Tore’s slide deck.

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What Happened to “Be Conservative in What You Do”?

March 26, 2014 - 11:04pm

A comment by Pieter E. Smit on my vSphere Does Not Need LAG Bandaids post opened yet another can of worms: vSphere behavior on uplink recovery.

Short summary: vSphere starts using an uplink as soon as its physical layer becomes operational, which might happen during ToR switch startup phase, or before a ToR switch port enters forwarding state.

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New webinar: Following Packets across Overlay Virtual Networks

March 25, 2014 - 11:11pm

Even though I’ve been talking and writing about various overlay virtual networking solutions for years (overview, Hyper-V, Amazon VPC, VMware NSX layer-2 and layer-3 gateways), there are still questions along the lines of “how does a packet get from A to B”, so Ethan Banks asked me to do a 1-hour session at upcoming Interop in Las Vegas.

Expanded version of the same presentation will be available as an update session to all current and future attendees of Overlay Virtual Networking webinar:

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Facebook Is Close to Having an IPv6-only Data Center

March 25, 2014 - 12:18am

Whenever I mention the idea of IPv6-only data centers, I get the usual question: “Sounds great, but is anyone actually using it?” So far, my answer was: “Yeah, I know a great guy in Norway that runs this in production” As of last week, the answer is way more persuasive: “Facebook is almost there.

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Thank you, Troopers!

March 23, 2014 - 11:57pm

I spent the whole last week immersed into security-spiced atmosphere of Troopers, a fantastic boutique security conference (like last year, they limited the number of attendees and sold out weeks before the conference).

I admit they totally spoiled me last year, but they managed to make the conference and all the accompanying events even better.

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Real-life OpenFlow Deployments

March 20, 2014 - 11:00pm

Talking about OpenFlow (and poking holes in it) is fun, but are there any real-life deployments (apart from highly-publicized Google’s internal network)? I tried to describe a few of them in my SDN 101 webinar.

Microsoft is using tap aggregation network in production, and I forgot to mention OpenFlow-based New Zealand IXP.

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Cisco IOS Supports RFC 6106 (RDNSS)

March 20, 2014 - 6:57am

When Enno Rey mentioned RFC 6106 support (why does it matter?) on Cisco IOS during the opening presentation of Troopers 2014 IPv6 security summit I got interested but remained a bit skeptical. When Eric Vyncke (sitting in the audience) started nodding, I knew it must be there. Finding the feature in IOS documentation turned out to be mission impossible.

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