Category: podcast

Do you need VXLAN in your data center or could you continue using traditional bridging? Do layer-2 fabrics make sense or are they a dead end in the evolution of virtual networking?

I tried to provide a few high-level answers in the Introduction to VXLAN video which starts the VXLAN Technical Deep Dive webinar. The public version of the video is now available on ipSpace.net Free Content web site.

You might be familiar with the idea of using BGP as an SDN tool that pushes forwarding entries into routing and forwarding tables of individual devices, allowing you to build hop-by-hop path across the network (more details in Packet Pushers podcast with Petr Lapukhov).

Researchers from University of Louvain, ETH Zürich and Princeton figured out how to use OSPF to get the same job done and called their approach Fibbing. For more details, listen to Episode 45 of Software Gone Wild podcast with Laurent Vanbever (one of the authors), visit the project web site, or download the source code.

Imagine you’d design your network by documenting the desired traffic flow across the network under all failure conditions, and only then do a low-level design, create configurations, and deploy the network… while being able to use the desired traffic flows as a testing tool to verify that the network still behaves as expected, both in a test lab as well as in the live network.

One of the typical questions I get in my SDN workshops is “how do you run control-plane protocols like LACP or OSPF in OpenFlow networks?”.

I wrote a blog post describing the process two years ago and we discussed the details of this challenge in the OpenFlow Deep Dive webinar. That part of the webinar is now available with Free ipSpace.net Subscription.

Content providers were using centralized traffic flow optimization together with MPLS TE for at least 15 years (some of them immediately after Cisco launched the early MPLS-TE implementation in their 12.0(5)T release), but it was always hard to push the results into the network devices.

PCEP and BGP-LS all changed that – they give you a standard mechanism to extract network topology and install end-to-end paths across the network, as Julian Lucek of Juniper Networks explained in Episode 43 of Software Gone Wild.

Many vendors talk about network automation these days, and almost all of them gloss over an important detail: automation works best when you manage to simplify things to the bare minimum needed to get the job done.

One of the vendors that focus on simplifying the network device configuration is Cumulus Linux.

You might remember the great idea David Barroso had last autumn – turn an Arista switch into an Internet edge router (SDN Internet Router – SIR). In the meantime, he implemented that solution in production environment serving high-speed links at multiple Internet exchange points. It was obviously time for another podcast on the same topic.

A while ago I started discussing the intricate technical details of fibbing (an ingenious way of implementing traffic engineering with traditional OSPF) with Laurent Vanbever and other members of his group, and we decided to record a podcast on this topic.

Things never go as planned in a live chat, and we finished talking about another one of his projects – software defined Internet exchange point (SDX), the topic of Episode 41 of Software Gone Wild.

When I asked “Are there any truly QoS-aware routing protocols out there?” in one of my SD-WAN posts, Marcelo Spohn from ADARA Networks quickly pointed out that they have one – Dynamic Link-State Routing Protocol.

He also claimed that DLSP has no scalability concerns – more than enough reasons to schedule an online chat, resulting in Episode 40 of Software Gone Wild. We didn’t go too deep this time, but you should get a nice overview of what DLSP is and how it works.

::: jump-link Enjoy the podcast :::

How do you capture all the flows entering or exiting a data center if your core Nexus 7000 switch cannot do it in hardware? You take an x86 server, load nProbe on it, and connect the nProbe to an analysis system built with ELK stack… at least that’s what Clay Curtis did (and documented in a blog post).

Obviously I wanted to know more about his solution and invited him to the Software Gone Wild podcast. In Episode 39 we discussed:

With the advent of layer-3 leaf-and-spine data center fabrics, it became (almost) possible to build pure layer-3-only data center networks… if only the networking vendors would do the very last step and make every server-to-ToR interface a layer-3 interface. Cumulus decided to do just that.

Like all other ipSpace.net webinars, the IPv6 Microsegmentation webinar starts with a brief description of the problem we’re trying to solve: the IPv6 first-hop security challenges.

For an overview of this problem, watch this free video from the IPv6 microsegmentation webinar, for more details, watch the IPv6 Security webinar.

Writing OpenFlow controllers that interact with physical hardware is harder than most people think. Apart from developing a distributed system (which is hard in itself), you have to deal with limitations of hardware forwarding pipelines, differences in forwarding hardware, imprecise abstractions (most vendors still support single OpenFlow table per switch), and resulting bloated flow tables.

Elisa Jasinska, Bob McCouch and I were scheduled to record a NetOps podcast with a major vendor, but unfortunately their technical director cancelled at the last minute. Like good network engineers, we immediately found plan B and focused on Elisa’s specialty: open-source tools.

What happens when network engineers with strong programming background and focus on open source tools have to implement network automation in a multi-vendor network? Instead of complaining or ranting about the stupidities of traditional networking vendors and CLI they write an abstraction layer that allows them to treat all their devices in the same way and immediately open-source it.