Last Chapter of Data Center Design Case Studies Is Published

A few days ago I completed the last chapter in the Data Center Design Case Studies book: building disaster recovery and active-active data centers. It focuses on application behavior and business needs, not on the underlying technologies; the networking technology part tends to be way easier to solve than the oft-ignored application-level challenges.

Troubleshooting VMware NSX on Software Gone Wild

When we started planning a VMware NSX-focused podcast episode with Dmitri Kalintsev, I asked my readers what topics they’d like to see covered. Two comments that we really liked were “how do I get started with VMware NSX?” and “how do I troubleshoot this stuff?

Case Study: Combine Physical and Virtual Appliances in a Private Cloud

Cloud builders are often using my ExpertExpress service to validate their designs. Tenant onboarding into a multi-tenant (private or public) cloud infrastructure is a common problem, and tenants frequently want to retain the existing network services appliances (firewalls and load balancers).

The Combine Physical and Virtual Appliances in a Private Cloud case study describes a typical solution that combines per-tenant virtual appliances with frontend physical appliances.

Is Controller-Based Networking More Reliable than Traditional Networking?

Listening to some SDN pundits one gets an impression that SDN brings peace to Earth, solves all networking problems and makes networking engineers obsolete.

Cynical jokes aside, and ignoring inevitable bugs, is controller-based networking really more reliable than what we do today?

Video: IPv6 High Availability Components

Last spring I ran an IPv6 High Availability webinar which started (not surprisingly) with a simple question: “which network components affect availability in IPv6 world, and how is a dual-stack or an IPv6-only environment different from what we had in the IPv4 world?

This part of the webinar is now available on content web site. Enjoy the video, explore other IPv6 resources on ipSpace net, and if you’re from Europe don’t forget to register for the IPv6 Security Summit @ Troppers in mid-March.

IPv6 Renumbering – Mission Impossible?

In one of the discussions on v6ops mailing list Matthew Petach wrote:

The probability of us figuring out how to scale the routing table to handle 40 billion prefixes is orders of magnitude more likely than solving the headaches associated with dynamic host renumbering. That ship has done gone and sailed, hit the proverbial iceberg, and is gathering barnacles at the bottom of the ocean.

Is it really that bad? Is simple renumbering in IPv6 world just another myth? It depends.

Network Programmability 101: Q&A Time

In the last video from the Network Programmability webinar Matt Oswalt answered numerous questions from the audience.

Tech Talks: Load Sharing and Entropy Labels in MPLS Networks

Load sharing in MPLS networks is always an interesting topic, and we couldn’t possibly avoid it during our MPLS-focused Tech Talkswatch the video.

After discussing the load sharing intricacies we briefly dabbled with the concept of entropy labels.

Lock-In Is Inevitable – Get Used to It!

For whatever reason (subliminal messages from vendor marketing departments?), I’m constantly brooding about the vendor lock-in, its inevitability, and the way supposedly disruptive companies try to use the fear of lock-in to persuade na├»ve customers to buy their products.

vLAG Caveats in Brocade VCS Fabric

Brocade VCS fabric has one of the most flexible multichassis link aggregation group (LAG) implementation – you can terminate member links of an individual LAG on any four switches in the VCS fabric. Using that flexibility is not always a good idea.

2015-01-23: Added a few caveats on load distribution

Improving ECMP Load Balancing with Flowlets

Every time I write about unequal traffic distribution across a link aggregation group (LAG, aka Etherchannel or Port Channel) or ECMP fabric, someone asks a simple question “is there no way to reshuffle the traffic to make it more balanced?

TL&DR summary: there are ways to do it, and some vendors already implemented them.

SDN Router @ Spotify on Software Gone Wild

Imagine you need a data center WAN edge router with multiple 10GE uplinks. You’d probably go for an ASR or a MX-series router, right? How about using a 2 Tbps ToR switch and an SDN solution to make it work with full Internet routing table?

If you happen to have iTunes on your computer, please spend 10 seconds rating the podcast before you start listening to it. Thank you!

Should I Go For CCDE or VCIX-NV?

I got a lengthy email from one of my readers a while ago, essentially asking a simple question: assuming I want to go return to my studies and move further than CCIE I currently hold, should I go for CCDE or the new VMware’s VCIX-NV?

Well, it’s almost like “do you believe in scale-up or scale-out?” ;) Both approaches have their merits.

Scaling Overlay Virtual Networks: The Problem

Every major hypervisor and networking vendor has an overlay virtual networking solution. Obviously they’re not identical, and some of them work better than others in large-scale environments – an interesting challenge we tried to address in the Scaling Overlay Virtual Networks webinar. As always, we started by identifying the potential problems.

Load Balancing Elephant Storage Flows

Olivier Hault sent me an interesting challenge:

I cannot find any simple network-layer solution that would allow me to use total available bandwidth between a Hypervisor with multiple uplinks and a Network Attached Storage (NAS) box.

TL&DR summary: you cannot find it because there’s none.

Network Programmability and SDN

What’s the difference between network programmability and SDN? Matt Oswalt explained his view on the topic in the Network Programmability 101 webinar.