Whenever there’s a weird request to do something totally illogical with BGP, there’s a knob in Cisco IOS to get it done (and increase the heartburn of CCIE candidates). Conditional Route Injection (the ability to insert more specific prefixes into BGP without having them in the IP routing table) is one of them.

Keep in mind: being a MacGyver is not a long-term strategy. Just because you can doesn’t mean that you should.

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.

Simonp made a perfectly valid point in a comment to my latest OVS blog post:

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.

The edited videos for my Enterprise IPv6 webinars have been published on my.ipspace.net. Enjoy!

Todd Hoff (of the HighScalability fame) sent me a link to an interesting video describing load-balancing mechanisms used at Google and how they evolved over time.

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: