Blessay — My EtherealMind

Using Underscores, Hyphens or CamelCase in Naming Standards

27th January 2012 By Greg Ferro 6 Comments

I’ve been considering a small but vital problem in naming conventions in Networking. Namely, the use of underscores and hyphens in object names and devices. It’s a hot topic for argument when the time comes for corporate standards (and when Network Engineers have beverages in a public house). Now, I figure that there are three possible grammar options for making names – hyphens, underscore and CamelCase.

Filed Under: Blessay, Blog, Operation, Opinion Tagged With: naming, network design, standards

Scaling Virtual Appliances With Embrane

12th December 2011 By Greg Ferro 1 Comment

Embrane uses concepts of IP Flows to scale virtual appliances. Embrane does this by managing IP flows and then directing to other appliances, in effect creating what I would call a two tier load balancing.

Filed Under: Blessay, Blog, Design Tagged With: appliances, network design, virtualization, vmware

Cisco, Culture of Buggy Code and the Failure of the TAC

16th November 2011 By Greg Ferro 53 Comments

In recent months I seem to have hit a lot of bugs in Cisco software. Across the board on the main software releases of IOS, NX-OS or IOS-SX I seem to be hitting a wide range of bugs, and some of them are pretty stupid. And I’ve realised that, in recent years, it has become so commonplace, so accepted that we actually plan our projects with time to test, locate and check for bugs. And that’s become an expensive and time-consuming problem.

Why do we put up with this ?

Filed Under: Blessay, Cisco, Rant

Cisco Nexus 5000 / 2000 Pricing Bundles and Fabric Extension Transceivers (FETs) vs 10GbaseSR SFPs.

3rd November 2011 By Greg Ferro 16 Comments

Recently I noticed that Cisco is selling “Fabric Ethernet Transceivers” for the Nexus switch family. Some research shows that these are replacements for 10GBaseSX SFP modules. Importantly, it’s cheaper to install new cabling than to buy 10BaseSR SFP+ modules.

Filed Under: Blessay, Blog, Cisco, Design Tagged With: Cisco, Design

Top Five Things About VXLAN – And Why It’s Full of Fail

16th September 2011 By Greg Ferro 9 Comments

It’s obvious #VXLAN was conjured up by a cloudtard. Simple minds devise simple solutions without seeing the complex problems they missed. Here are five things that VXLAN tells us about the networking industry.

Filed Under: Blessay, Blog Tagged With: vmware

Switch Fabrics: Input and Output Queues and Buffers for a Switch Fabric

6th September 2011 By Greg Ferro 3 Comments

Now that this has established that a Switch Fabric has buffers, I want to flip back into something practical about this application. Lets use an example of four servers connecting to single switch and sharing an Ethernet Storage Array. The array might be using iSCSI or FCoE to delivery SCSI applications to the Servers. The nature of storage traffic is such that it has transient spikes in traffic that must maintain low latency and should not be dropped.

Filed Under: Blessay, Blog

Soft Switching Fails at Scale

9th July 2011 By Greg Ferro 29 Comments

There is a significant camp of software developers who are developing software switching solutions for hypervisors. Which is nice, I guess. The use of software switching in the hypervisor has some good points but, in my view they are heavily outweighed by the bad. I present the use case, and show that software

Filed Under: Blessay, Design, Security Tagged With: Design, hypervisor, vmware

What Is the Definition of a Switch Fabric ?

30th June 2011 By Greg Ferro 26 Comments

The marketing people in IT tend to be overwhelmed by complexity and deep technology. For many liberal arts graduates, they take the drowning option and latch onto certain terms and then grossly abuse it. The most egregious abuse today is “cloud” but “fabric” comes a close second. In this series of posts I want to look at what is a FABRIC and provide a canonical look at what it does and how it works for us.

Filed Under: Blessay, Blog Tagged With: Blessay, Design, trill, worklife

Cisco C6500 Service Modules – Not My Choice, Now.

19th June 2011 By Greg Ferro 10 Comments

These all suggest that the time for planning and designing Service Modules is over. There are no suggestions that service modules for the Nexus 7000 will be developed that I can see. I can prognosticate that it would slow down the development of the core switch / route / performance functions, and it will be some years before those core capabilities is complete enough that service modules would become viable product development tasks — they might be in development, but not much chance of going into production. [^1]

Do I sound bitter about Service Modules ? A bit. I’ve had a number of hard to solve problems that lasted months before code fixes arrived. I’ve been fan of the NAM but the price is now far removed from it’s practical value. USD$30K List is way over priced for its capabilities and even with a 30% discount, you can buy a lot of network management systems that deliver much better functions and features for that price.

Filed Under: Blessay, Cisco, Design Tagged With: Cisco, Design, network design

VMware: Let’s Get Logical – The Case for OpenFlow Network Virtualization (and Their Failed Network Plans)

2nd June 2011 By Greg Ferro 4 Comments

VMware has made several strategic moves to implement dynamic networking – vSwitch, vDS, Nexus 1000 (in partnership with Cisco), vCloud External Networks (using MAC in MAC of all things) and have basically failed to deliver overlay technology without implementing technology in the network itself. Equally, VMware hasn’t been willing to engage with the networking vendors to develop technologies that would solve this problem – VNtag / VEPA/ VEP combined with TRILL / SPBB, instead letting them argue amongst themselves. VMware attempt with vCloud networking using MACinMAC encapsulation seems to have failed and stalled and is getting another attempt using MACinIP. VMware/Xen/HyperV are all desperate to have a more dynamic network that can be controlled from their software and this might be where OpenFlow gets a big lift – as a configuration engine.

Filed Under: Blessay, Blog, Design Tagged With: Design, industry, openflow