Ivan Pepelnjak

Author Archives: Ivan Pepelnjak

Is BGP Really that Complex?

Anyone following the popular networking blogs and podcasts is probably familiar with the claim that BGP is way too complex to be used in whatever environment. On the other hand, more and more smart people use it when building their data center or WAN infrastructure. There’s something wrong with this picture.

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Using Macvlan and Ipvlan with Docker on Software Gone Wild

A few weeks after I published Docker Networking podcast, Brent Salisbury sent me an email saying “hey, we have experimental Macvlan and Ipvlan support for Docker” – a great topic for another podcast.

It took a while to get the stars aligned, but finally we got Brent, Madhu Venugopal, John Willis and Nick Buraglio on the same Skype call resulting in Episode 57 of Software Gone Wild.

Building a L2 Fabric on top of VXLAN: Arista or Cisco?

One of my readers working as an enterprise data center architect sent me this question:

I've just finished a one-week POC with Arista. For fabric provisioning and automation, we were introduced to CloudVision. My impression is that there are still a lot of manual processes when using CloudVision.

Arista initially focused on DIY people and those people loved the tools Arista EOS gave them: Linux on the box, programmability, APIs… However

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Optimize Your Data Center: Ditch the Legacy Technologies

In our journey toward two-switch data center we covered:

It’s time for the next step: get rid of legacy technologies like six 1GE interfaces per server or two FC interface cards in every server.

Need more details? Watch the Designing Private Cloud Infrastructure webinar. How about an interactive discussion? Register for the Building Next-Generation Data Center course.

Feedback: Layer-2 Leaf-and-Spine Fabrics

Occasionally I get feedback that makes me say “it’s worth doing the webinars ;)”. Here’s one I got after the layer-2 session of Leaf-and-Spine Fabric Designs webinar:

I work at a higher level of the stack, so it was a real eye opener especially with so much opinionated "myths" on the web that haven't been critically challenged such as [the usefulness of] STP.

There’s more feedback on this web page where you can also buy the webinar recording (or register for the next session of the webinar once they are scheduled).

Can Enterprise Workloads Run on Bare-Metal Servers?

One of my readers left a comment on my “optimize your data center by virtualizing the serversblog post saying (approximately):

Seems like LinkedIn did it without virtualization :) Can enterprises achieve this to some extent?

Assuming you want to replace physical servers with one or two CPU cores and 4GB of memory with modern servers having dozens of cores and hundreds of GB of memory the short answer is: not for a long time.

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What Are The Problems with Broadcom Tomahawk? We Don’t Know

One of my readers has customers that already experienced performance challenges with Tomahawk-based data center switches. He sent me an email along these lines:

My customers are concerned about buffer performance for packets that are 200 bytes and under. MORE IMPORTANTLY, a customer informed me that there were performance issues when running 4x25GE connections when one group of ports speaks to another group.

Reading the report Mellanox published not so long ago it seems there really is something fishy going on with Tomahawk.

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