Blog Posts in December 2014
After discussing the basics of MPLS, MPLS-TE and LDP, and the relationship between FECs, LDP and BGP, Seamus and myself focused on another interesting topic: how MPLS protocol stack uses RSVP to implement traffic engineering.
One of the networking engineers using my ExpertExpress to validate their network design had an interesting problem: he was building a multi-tenant VLAN-based private cloud architecture with each tenant having multiple subnets, and wanted to route within the tenant network as close to the VMs as possible (in the ToR switch).
He was using Nexus 5600 as the ToR switch, and although there’s conflicting information on the number of VRFs supported by that switch (verified topology: 25 VRFs, verified maximum: 1000 VRFs, configuration guide: 64 VRFs), he thought 25 VRFs (tenant routing domains) might be enough.
The edited videos for Scaling Overlay Virtual Networking webinar are available on ipSpace.net Content site. Nuage Networks sponsored the webinar; the videos are thus publicly available (without registration).
Highly customizable high-speed virtual switch written in Lua sounds great, but is it really that easy to use? Simon Leinen was kind enough to get me in touch with Alex Gall, his colleague at Switch, who's working on an interesting project: implementing L2VPN over IPv6 with Snabb Switch.
Facebook published their next-generation data center architecture a few weeks ago, resulting in the expected “revolutionary approach to data center fabrics” echoes from the industry press and blogosphere.
In reality, they did a great engineering job using an interesting twist on pretty traditional multi-stage leaf-and-spine (or folded Clos) architecture.
Obviously the page you're referring to is a quick-and-dirty benchmark. If you wanted the optimal numbers, you would have to tune quite a few parameters just like for hardware benchmarks (sysctl kernel parameters, Jumbo frames, ...).
While he’s absolutely right, this is not the performance data a typical user should be looking for.
If you want to get a free copy of my Overlay Virtual Networks in Software-Defined Data Centers book, download it now. The offer will expire by December 15th.
If the rest of the blog post feels like Latin, you SHOULD watch the Load Balancing and Scale-Out Application Architecture webinar.
The beginning of the story resembles traditional enterprise solutions:
Stumbled upon a hilarious description of challenges encountered when trying to scale distributed systems (cluster of controllers running centralized control plane comes to mind).
It starts with “If someone tells you that scaling out a distributed system is easy they are either lying or drunk, and possibly both,” and gets better and better. Enjoy!
In his The Case for Hybrids blog post Mat Mathews described the Hotel California effect of public clouds as: “One of the most oft mentioned issues with public cloud is the difficulty in getting out.” Once you start relying on cloud provider APIs to provide DNS, load balancing, CDN, content hosting, security groups, and a plethora of other services, it’s impossible to get out.
Interestingly, the side effects of public cloud deployments extend into the realm of application programming, as I was surprised to find out during one of my Expert Express engagements.
In my presentation @ SDN Meetup in Stockholm, I tried to answer a simple question: “Should I really program my network?” and obviously had to start with an even simpler one: “What is SDN?”
One of my readers is struggling with the aftermath of marketing gimmicks:
We will be implementing a new network soon, and we're discussing P-routers versus regular routers versus switches. I'm looking for arguments to go one way or the other.