I’ve recently been coming up to speed on an innovative, disruptive new technology named Software Defined Networking (SDN). It’s likely the most significant development in the networking industry for many years to come. With the promise of substantially streamlining network provisioning, management and configuration, SDN strictly speaking is about decoupling the control (Layer3) and forwarding (Layer2) planes. There is certainly the potential for rippling disruptions in the established network industry (Cisco…) as the “brains” for the network move towards software and out of the hardware.
My approach to rapidly familiarizing with any new technology is to read and absorb as much as possible, while at the same time getting hands-on exposure. Accordingly, here are some suggested resources-
1. Network World offers regular coverage of SDN-related updates, here is a recent overview. For a less technical viewpoint, read this article from Economist magazine. For networking techies, go to the Open Networking Summit , and check out their Video archive of conference sessions. Nick McKeown’s keynote video “How SDN Will Shape Networking” is an excellent introduction.
2. Register for the free OpenFlow Tutorial to learn about the primary SDN protocol, OpenFlow. You’ll get to build a real SDN switch, capture OpenFlow packets and maybe get into some Python.
Another useful free online course is the SDN class offered by Coursera , taught by Dr. Nick Feamster of Georgia Tech. Keep in mind this class is highly technical, and assumes a prior advanced knowledge of network engineering.
Enjoy and Happy Fourth!
P.S. On Twitter, here are my favorite sources on SDN – @etherealmind @openflownetwork @sdn_news @openNetSummit @openflow @nicira
In recent months, I’ve been assembling a lab to provide a test-bed for various network and infrastructure applications. My current role at Dell often involves multi-vendor networks, so having an easily accessible test bed including Cisco, Dell, Juniper and HP devices can be very useful for interoperability troubleshooting such as Spanning Tree Protocol.
I wanted to provide a robust virtual infrastructure, and in my experience that usually means VMware. I’m fortunate enough to have extra ESX Enterprise and Plus licenses from VMware partner registration. To utilize all the most useful VMware features like Vmotion and HA, a shared storage system is required. In addition, I wanted to incorporate as many iSCSI “best practices” such as using dedicated infrastructure, dedicated VLAN and Jumbo Frames without breaking the bank.
Without an extra $1-2 K on hand to go out and purchase a full-blown iSCSI SAN such as EqualLogic or Compellent (shameless Dell plugs), and already having a home NAS set up, my goal was to assemble a SAN utilizing as much extra or existing hardware as possible and of course limiting new expenses.
For my purposes, performance took precedence over storage capacity, and redundancy was not as important as keeping costs down (and streamlining design).
- DISK: Crucial 128 GB m4 2.5-Inch Solid State Drive SATA 6Gb/s CT128M4SSD2 – $125
- NETWORK: Dell PowerConnect 5324 1GB 24-port switch, Jumbo Frame support (used, Ebay) – $120
- Intel Gigabit NIC – $37
- SERVER: Starwind iSCSI SAN Free edition
- MISC.: 9 Pin null modem cable (console for Dell 5324) – $10
- Mounting kit for SSD – $3
- TOTAL – $295 (not incl. tax or shipping)
- I was able to re-purpose an unused PC for the iSCSI Starwind server, w/dual core CPU, 3 GB RAM, and Windows 7 Home. Starwind Free Edition doesn’t require a server OS so that was helpful.
- The Intel GigE NIC was installed into the PC for a dedicated NIC to the iSCSI network, separate from the LOM.
- The SSD was installed into the spare PC, and presented as a new iSCSI device.
- I thought I had a 9 pin F-F cable already but didn’t…not common these days, anyway got lucky finding the last one in stock at Fry’s 🙂
- For the SAN server, ideally this should be a Windows or Linux server O/S, however my hardware was more than adequate.
- Starwind is a good option for Windows users, OpenNAS is an option for Linux folks.
- JUMBO FRAMES are a MUST!! Jumbo Frames must be enabled end to end for optimal performance, and must be supported on the physical switch for starters. In addition, you’ll need to update VMware components for Jumbo frame support including vSwitch, port group, VMkernel, and guest OS NIC adapter. Here’s a great article on configuration for VSphere 4.
- It’s always a good practice to create a separate VLAN for iSCSI as well.
- LAN cables not included
- I’m very pleased with my new iSCSI-based shared storage system, supporting VSphere 4 on (2) Dell SC1425 64-bit 1U servers. Responsiveness is snappy within VI Client, as well as within RDP for Windows guest VM’s.
- VMotions on shared storage: 20-30 seconds, not bad compared to Enterprise-class SAN’s which I’ve observed at 10-20 seconds.
I’ve known about but shied away from powerline-based adapters in the past. Working in data centers on a routine basis, I’m used to CAT5/6 whenever possible, and wireless second. Having just moved into a new house with enough free space in the garage for a lab setup, I wanted to extend my network without playing the roll-your-own cable game, and stressing my knees while drilling holes, so I decided to test out the ZyXEL HomePlug Powerline adapter.
Have to say that I was impressed at how simple setup was, just connect one adapter w/LAN cable into my core switch, install the other adapter into outlet in the garage and was online in no time. There is an encryption feature too, though I probably won’t be using it. The marketed speed is 200 Mbps which I have not yet tested, however speed tests through my ISP (Verizon FiOS) to the Internet were comparable to wired connections.
I’m currently evaluating network analysis tools to support with assessment projects at Dell.
On a recent onsite engagement, a colleague suggested that I check out Fluke Networks’ ClearSight Analyzer for application analysis. I was really impressed with its ease-of-use, and ability to quickly highlight application layer traffic. It provides real-time monitoring through an intuitive, appealing display.
ClearSight Analyzer also supports Wireshark format captures, though it appeared to provide reduced detail for analysis compared to native ClearSight capture files. It also highlights errors or issues detected with a particular network flow. I’m finding that more projects are requiring network assessment and analysis to extend up to layer 7, so this tool from Fluke definitely deserves a closer look.
As well, I plan to dive deeper into Opnet’s Application Performance management Suite, in particular AppResponse Expert.
In the meantime, I always like to plug open-source projects, and Wireshark is absolutely a must-have tool for network analysis. It does demand some investment to uncover more advanced functionality, but the effort is well worth it simply for the exposure to application-specific protocols and data traffic.