Network design, architecture, thinking, working. Tech.
Short Answer is “It depends, but usually yes.” Long answer follows with a discussion of launch power, receiver sensitivity, and cable losses.
I’m responding to Brad Hedlund’s post “On optimizing traffic for network virtualization” where he seems to missed a key point. It’s about cost of ownership in terms of ability to troubleshoot.
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.
I got this question and I guess it may not be obvious to everyone so I’ll have a shot at answering it.
Technology advances in ASIC hardware have resulted in substantial improvements in switching performances of routers and switches. However, the routing processes are still dependent on CPU speeds. What are the existing limitations in router/switch models which prevent route computations from being performed in hardware?
I was reading a white paper by Panduit that claims that 10GBaseT is suitable for use. I’ve been critical of Cat6A cable and believe that it’s not suitable for data centre use.
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.
A short summary of the Fibre Cable Connectors, description and some notes on usage. This is summary notes and intended for reference.
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
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.
With all the talk about Layer 2 Multipath (L2MP) designs going on, I just want to point out a fundamental change in the way many people approach network design. It’s seems that this point has been lost somewhere in the discussion of protocols.
The Spanning Tree Protocol blocks looped paths, and in a typical networks this means that bandwidth is unevenly distributed. Of course, we might use PVST or MST to provide a rough sharing of load by splitting the spanning tree preferences for different VLANs, but the design still doesn’t change overall. The basic point is that there is a LOT of bandwidth that is never evenly utilised – and that means wasted power, space and cooling (which costs more than the equipment itself).
