Network Design — Keeping it simple
Since the dawn of time people have skirted best practice and banged together networks, putting the proverbial square peg in the esoteric round hole. For example, new vendor XYZ’s solution has brought in new requirements for deployment. While it may seem easier for to throw together a new firewall, a switch, and maybe some additional routes, and of course Tom‘s favorite… NAT — but where does it stop!? As you continue to pile layer upon layer into your uninspired network design you will soon realize that your “beautiful network” has become the ugly duckling that you need help fixing.
That leads me to my first point. Complex systems are expensive, not only in CAPEX, but in OPEX. When you design and build a network, you have to ensure that you are not building something that no one else has dreamed up, or else your problems will also be unique. And without the additional money to hire top tier engineers, you could be short staffed, or worse yet, facing the problem on your own. The more complex your network becomes, the more likely it is to fail. As I’m often quoted as saying, “The complexity required for robustness, often goes Continue reading
If Cisco Could Be Split Up, What Could Go ?
Following the breakups of IBM and HP as they divest the low profit divisions and EMC under a some pressure to disband the Federation, the same question is often raised about Cisco but what could go ?
The post If Cisco Could Be Split Up, What Could Go ? appeared first on EtherealMind.
“Range of fields” in awk
This is asked very often, and the solution isn't always obvious (if at all).Learning NSX, Part 16: Routing to Multiple External VLANs
This is part 16 of the Learning NSX series, in which I will show you how to configure VMware NSX to route to multiple external VLANs. This configuration will allow you to have logical routers that could be uplinked to any of the external VLANs, providing additional flexibility for consumers of NSX logical networks.
Naturally, this post builds on all the previous entries in this series, so I encourage you to visit the Learning NVP/NSX page for links to previous posts. Because I’ll specifically be discussing NSX gateways and routing, there are some posts that are more applicable than others; specifically, I strongly recommend reviewing part 6, part 9, part 14, and part 15. Additionally, I’ll assume you’re using VMware NSX with OpenStack, so reviewing part 11 and part 12 might also be helpful.
Ready? Let’s start with a very quick review.
Review of NSX Gateway Connectivity
You may recall from part 6 that the NSX gateway appliance is the piece of VMware NSX that handles traffic into or out of logical networks. As such, the NSX gateway appliance is something of a “three-legged” appliance:
- One “leg” (network interface) provides management connectivity among the gateway appliance and Continue reading
Let’s look at: UCS B-Series Blade to IOM Connectivity
Being a network engineer one of the things that I really wondered about in the UCS B Series was how exactly do those server blades talk the IOM, now from the IOM to the FI’s its relatively simple you’ve got physical cables. However within the UCS B-Series chassis there are no cable per-say within the […]
Write Like You Mean It (Part 2)
In the first part of this two part series, I talked about why it’s important to learn to write — and to learn to write effectively. But how do you become an effective writer? I started with the importance of reading, particularly difficult and regular reading across a broad array of topics. Is there anything else you do to improve your writing skills? Yes — specifically, get yourself edited, and get some practice.
Hey — I’m a pretty good writer, why do I need to get myself edited? After all, I’ve written nine books, hundreds of articles, tens of research papers, and… But that’s just the point, isn’t it? I wrote several large papers (at least I considered them large at the time) while I was in the Air Force, but they never seemed to have the impact I thought they should have. Weren’t they well written? Weren’t they well organized? Well researched? As it turns out, no, not really. I started on my first white paper just after I’d started in the Cisco TAC, reading through the EIGRP code and writing a paper — for internal use only — based on what I could find. Done and I Continue reading
Learn SDN or Go for Traditional Cisco Certs?
At Interop ’14 New York a few weeks ago, Ethan Banks collected four fellow CCIEs together for a panel discussion about whether we should be studying newer SDN technologies or pursuing the same old traditional certifications. I’ve been getting that kind of question for a while. This post summarizes a few points I took away from the other panelists at the show, with a promise to give some of my own thoughts in the post that follows.
Trade Articles
We had a pretty good spread of competing ideas from the four panelists. I couldn’t sit there and furiously write what the others were saying, for later blogging… but thankfully, there were a couple of professionals in the room! While Interop doesn’t normally post audio or video of the sessions, there have been a few trade press articles written about what was discussed the session:
Wendell’s Learnings from the Others
I came away with several ideas from the other panelists that either taught me something or made an existing opinion much stronger.
First, it seemed that there was general agreement that cloud, DevOps, and automation were the point. SDN, which was in the session title and Continue reading
Applying the Theory of Constraints to network transport
For those of you into expanding your experience through reading, there is a foundational reference at the core of many MBA programs. The book, Eliyahu Goldratt’s The Goal, introduces a concept call the Theory of Constraints. Put simply, the Theory of Constraints is the premise that systems will tend to be limited by a very small number of constraints (or bottlenecks). By focusing primarily on the bottlenecks, you can remove limitations and increase system throughput.
The book uses this theory to talk through management paradigms as the main character works through a manufacturing problem. But the theory actually applies to all systems, making its application useful in more scenarios than management or manufacturing.
Understanding the Theory of Constraints
Before we get into networking applications, it is worth walking through some basics about the Theory of Constraints. Imagine a simple set of subsystems strung together in a larger system. Perhaps, for example, software development requires two development teams, a QA team, and a regressions team before new code can be delivered.
If output relies on each of these subsystems, then the total output of the system as a whole is determined by the lowest-output subsystem. For instance, imagine that SW1 Continue reading
Learning NSX, Part 16: Routing to Multiple External VLANs
This is part 16 of the Learning NSX series, in which I will show you how to configure VMware NSX to route to multiple external VLANs. This configuration will allow you to have logical routers that could be uplinked to any of the external VLANs, providing additional flexibility for consumers of NSX logical networks.
Naturally, this post builds on all the previous entries in this series, so I encourage you to visit the Learning NVP/NSX page for links to previous posts. Because I’ll specifically be discussing NSX gateways and routing, there are some posts that are more applicable than others; specifically, I strongly recommend reviewing part 6, part 9, part 14, and part 15. Additionally, I’ll assume you’re using VMware NSX with OpenStack, so reviewing part 11 and part 12 might also be helpful.
Ready? Let’s start with a very quick review.
Review of NSX Gateway Connectivity
You may recall from part 6 that the NSX gateway appliance is the piece of VMware NSX that handles traffic into or out of logical networks. As such, the NSX gateway appliance is something of a “three-legged” appliance:
-
One “leg” (network interface) provides management connectivity among the gateway appliance and Continue reading
Thinking Through Title II Reguation
Over at CircleID, Geoff Huston has a long’ish article on Title II regulation of the Internet, and the ideals of “net neutrality.” The reasoning is tight and strong — his conclusion a simple one: At its heart, the Internet access business really is a common carrier business. So my advice to the FCC is to […]
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Packet Reordering and Service Providers
My “Was it bufferbloat?” blog post generated an unexpected amount of responses, most of them focusing on a side note saying “it looks like there really are service providers out there that are clueless enough to reorder packets within a TCP session”. Let’s walk through them.
Read more ...Last Chance at Chassis Switch Saloon
In recent network designs, the big, hot and heavy chassis switch has become the last option for a number of reasons. Switch Performance and Capacity. Port Density In the past, the most common decision for buying a chassis has been port density. A chassis backplane provides a high speed connection for the line cards to […]
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Don’t sign that CFAA petition
This White House petition reforming the CFAA/DMCA is foolish. Don't sign it.The problem is that "reform" means nothing. It doesn't state exactly which reforms the petitioners want. That means politicians will deliver on what they asked, reforming the DMCA/CFAA, but in the opposite direction. The mood in Washington D.C. is one of great fear of Chinese hackers and cyberterorrists. Once you start reform, these forces will take over and drive it the other way.
In other words, the petition is like somebody on a submarine saying "the air is stuffy, let's open a window and let some fresh air in". It's best to keep that window closed rather than getting drowned.
A second problem is the declaration that "safe code" is the problem. That will encourage law-makers to solve that problem with legislation requiring manufacturers to follow rules -- without needing weaken the DCMA/CFAA. This is bad. So far rule-based security like Common Criteria and PCI certification have proven to be an enormous burden that does little to address the problem.
Lastly, there is the problem that this is a "White House" petition. The president doesn't make laws, s/he enforces them. It's appropriate to petition the White House Continue reading
How to Get into the Top N%
Michael Church wrote an interesting answer on Quora, describing a logarithmic scale of programming skills and (even more importantly) hints to follow to get from n00b into the top N% (for some small value of N):
- Budget 7–14 years;
- Study voraciously;
- Build things when you don’t know that you’ll succeed;
- Network to get new ideas;
- Job hop when you stop learning.
Replace “programmer” with “networking engineer” and read the whole answer ;)
HP SDN App Store Launches
HP’s SDN App Store has finally seen the light of day. This is intended to be a common platform for users and developers, to find and distributed real-world, practical SDN applications. Some of the launch apps include:
- Network Optimizer, for automated QoS for Lync
- Network Protector, for security & posture assessment
- LoadMaster – Load balancing
It’s interesting to look at the price points for applications. They are certainly not $0.99 apps, but they are still cheaper than typical ‘Enterprise’ software. I think it will take us a while to figure out what the right level of ‘value’ is.
HP has done well to put together a platform that developers can use to distribute SDN applications. It’s not an easy task to put together all of the back-end work required for something like this. It’s not simply hosting a website, it’s figuring out all the legal & financial implications, the support mechanisms, etc. There’s a lot of non-technical effort that goes into this.
The only challenge is that currently it is for SDN apps that use the HP VAN SDN Controller, which will limit the size of the market. I’m hoping that in future it will work with OpenDaylight. That will expand Continue reading
Big Problems Often Require Big Solutions
You can ignore big problems but they need big solutions to remove them from the agenda.
The post Big Problems Often Require Big Solutions appeared first on EtherealMind.
PQ Show 34 – Cloudflare Keyless SSL
A couple of weeks ago, Cloudflare announced a new solution that allows DDOS Protection, Caching and application firewalls of SSL encrypted traffic without handing over the private key. This is a significant breakthrough for companies. Many companies have strong controls over private keys that prevent external sharing. More often the simple cost of key ceremonies is punitive to the business.
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The post PQ Show 34 – Cloudflare Keyless SSL appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Super NORMAL
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HP's slide presentation from the design forum, OpenFlow-hybrid Mode, gives an overview of hybrid mode OpenFlow and its benefits. The advantage of hybrid mode in leveraging the proven scaleability and operational robustness of existing distributed control mechanisms and complementing them with centralized SDN control is compelling and a number of vendors have released support, including: Alcatel Lucent Enterprise, Brocade, Extreme, Hewlett-Packard, Mellanox, and Pica8. HP's presentation goes on to propose enhancements to the OpenDaylight controller to support hybrid OpenFlow agents.
InMon recently built a hybrid OpenFlow controller and, based on our experiences, this article will discuss how integrated hybrid mode is currently implemented on the switches, examine operational issues, and propose an agent profile for hybrid OpenFlow designed to reduce operational complexity, particularly when addressing traffic engineering use cases such as DDoS mitigation, large flow marking and large flow steering on ECMP/LAG networks.
Mechanisms for Optimizing LAG/ECMP Component Link Utilization in Networks is an IETF Continue reading