Blog Posts in May 2016
Is XMPP Control- or Management-Plane Protocol?
My readers are consistently asking me whether XMPP and OVSDB are control- or management-plane protocols (to make matters worse, publicly available information tends to be confusing).
For example, one of them wrote…
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
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.
OpenFlow Table-Type-Patterns and Vendor Hype
Network Computing recently published an article with a promising title “Network Disaggregation: Opening the Last Back Box” and a subtitle I could totally relate to: “switch ASICs must be opened up to provide real networking flexibility.”
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 servers” blog 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.
Model-Driven Networking on Software Gone Wild
The Model-driven Networking seems to be another buzzword riding on top of the SDN wave. What exactly is it, how is it supposed to work, will it be really vendor-independent, and has anyone implemented it? I tried to get some answers to these questions from Jeff Tantsura, chair of IETF Routing Area Working Group, in Episode 55 of Software Gone Wild.
OpenStack Networking, Availability Zones and Regions
One of my ExpertExpress engagements focused on networking in a future private cloud that might be built using OpenStack. The customer planned to deploy multiple data centers, and I recommended that they do everything they can to make sure they don’t make them a single failure domain.
Next step: translate that requirement into OpenStack terms.
Yeah, Blame It on Cisco
A Technology Market Builder (in his own words) from a major networking vendor decided to publish a thought leadership article (in my sarcastic words) describing how Cisco’s embrace of complexity harmed the whole networking industry.
Let’s see how black this kettle-blaming pot really is ;), and make sure to have fun reading the comments to the original article.
Don’t miss a day full of SDN, security, microsegmentation and hands-on NSX
Gabi Gerber (with a bit of help from my side) is organizing another set of SDN events in Zurich (Switzerland) in early June.
In the morning of June 7th we’ll talk about software-defined security:
Let’s Focus on Realistic Design Scenarios
An engineer working for a large system integrator sent me this question:
Since you are running a detailed series on leaf-and-spine fabrics these days, could you please suggest if following design scenarios of Facebook and Linkedin Data centers are also covered?
Short answer: No.
The moment an IETF working group agrees on a protocol someone starts creating extensions. PCEP is no exception; in the last part of the BGP-LS and PCEP webinar Julian Lucek talked about some of them.
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.
Running BGP Route Reflector in a Virtual Machine
The BGP-based SDN Solutions webinar triggered another interesting question from one the attendees:
It seems like the BGP route reflector functionality can be implemented as a Virtual Machine. Will a VM have enough resources to meet the requirements of a RR?
Short answer: Yes.
Overlay Virtual Networking: Featured Webinar of May 2016
The featured webinar in May 2016 is the Overlay Virtual Networking webinar and in the featured videos (the ones marked with a star) you'll find introduction to overlay virtual networking and deep dive into flooding and MAC address learning in layer-2 overlay virtual networks.
BGP Route Maps and Continue Feature Limitations
One of my ExpertExpress engagements focused on BGP route maps and setting BGP attributes based on BGP communities, so I wanted to brush up my RouteMapFoo before the online session.
Here are a few (not-so-unexpected) results gathered from IOSv release 15.5(3)M.
API Does Not SDN Make
Vendors that slapped API on top of their CLI are quick to claim that they SDN-enabled their boxes.
Not so fast. As I explained in SDN 101 webinar, programmable access to network devices is nice (less so when you're forced to use a vendor-specific API), but it's not SDN.
Unexpected Recovery Might Kill Your Data Center
Here’s an interesting story I got from one of my friends:
- A large organization used a disaster recovery strategy based on stretched IP subnets and restarting workloads with unchanged IP addresses in a secondary data center;
- Once they experienced a WAN connectivity failure in the primary data center and their disaster recovery plan kicked in.
However, while they were busy restarting the workloads in the secondary data center, and managed to get most of them up and running, the DCI link unexpectedly came back to life.
Software-Defined Security and VMware NSX Events
I’m presenting at two Data Center Interest Group Switzerland events organized by Gabi Gerber in Zurich in early June:
- In the morning of June 7th we’ll talk about software-defined security, data center automation and open networking;
- In the afternoon of the same day (so you can easily attend both events) we’ll talk about VMware NSX microsegmentation and real-life implementations.
I hope to see you in Zurich in a bit more than a month!
Response: Are Open-Source Controllers Ready for Carrier-Grade Services?
My beloved source of meaningless marketing messages led me to a blog post with a catchy headline: are open-source SDN controllers ready for carrier-grade services?
It turned out the whole thing was a simple marketing gig for Ixia testers, but supposedly “the response of the attendees of an SDN event was overwhelming”, which worries me… or makes me happy, because it’s easy to see plenty of fix-and-redesign work in the future.
Setting Terminal Width in Cisco IOS
This must be old news to most of you (I managed to stay away from CLI for way too long), but I was pleasantly surprised that you can set terminal width (not just length) in Cisco IOS.