In the process of building cloud networks over the last 3 months, it has become clear that a lot of people have problems accepting that Overlay Networking is a viable technology. The current1 version of the future in Software Defined Networking (SDN) in the Data Centre will use overlay networks using technologies like VXLAN, NVGRE […]
I’ve been quiet for some time because I’ve been working on a couple of eBooks. Today, I pleased to publicly announce my first ever eBook called “The Arse First Method of Technical Blogging”.. I wrote this book to answer the question that I get asked a lot – “How do you write so many blog posts?”. So I started to write a blog post until I realised it would take too long. A year later I have taken it far enough to release an eBook.
I woke up at three o’clock this morning with a thought racing around my brain – am I building a Hosting Cathedral or Cloud Bazaar ? My data centre is like a cathedral – regimented rows of seats, full of disciplined and controlled resources all looking towards the technical priests for inspiration and direction. Each […]
I was reviewing some presentations on monitoring and visual charts from the monitorama conference. This caught my eye for a 3D representation for unicast, Multicast and Broadcast traffic (using Barycentric co-ordinates if I understand correctly). Barycentric representation uses 3D-coordinate system. Presentation can be found here Monitoring for Humans Can’t remember how I found this link Monitoring […]
Join our webinar about the nCloudX controller abstracts commonly deployed network routers, switches, firewalls and application delivery controllers, along with traditional tools like BGP, OSPF, MPLS and VRFs. Cloud operators and as well as cloud consumers can provision the network using predefined templates that remove the need to individually configure the underlying network hardware.
Looking at using SDN & OpenFlow to perform a firewall migration on a rule by rule basis instead of using any of the other nasty, crufty hacks. Very useful when you want to find an easier and low risk way to get rid of those pesky CheckPoint firewall products.
Google has decided to end their Reader product that provided an interface to RSS. On the whole, it’s a good thing even though I’m unhappy that I have to change. I’m confident that something better will arrive so I will wait peacefully & patiently for the Internet to provide. Take a deep breath nerds. The […]
Comparing the pricing strategies of Cloud Services to Project Budgets isn’t that hard. Lets cover that here. A common theme in cloud based service is “per user” pricing. A service to provide a VPN authentication service like Pertino looks quite attractive at USD$10 per user. Most engineers will intuitively know that “per user” pricing is always more expensive than “own it yourself” solution but it can be hard to justify.
I was going to call this article “Ethernet Switches for Virtualisation Engineers” but, really, everyone should have some understanding of the internals of an Ethernet switch. But particularly I want to focus on how multicast and broadcasts are handled in a high speed, low latency environment like a Data Centre Network.
It’s vital to understand that latency is critical to your application performance. It is common for a single transaction to take hundreds of round trips so a small increase in latency on each round trip has a large impact on the perceived performance. The client will send a chunk of data and wait for acknowledgement. Even setting up the TCP connection takes a few round trip – remember that TCP sessions are setup, and each data transfer is confirmed.
A modern network switch will have latency around 10 microseconds. The Cisco Nexus 7000 is about 8 microseconds & Brocade VDX 8770 claims less than 4 microseconds. There are many reasons why a switch can be faster or slower but I’ll look at a specific example
Remember, the latency interval is the time taken to receive a packet, decode the address, lookup the forwarding table, switch the packet (and copy it if needed) and transmit out of an Ethernet interface. That’s really fast processing. How does an Ethernet switch do this ?
Network Engineers have to manage a lot of information. Products, technologies, textbooks, study notes and research material as well as new protocols and features. Just simple tasks like keeping product manuals handy for 40 or 50 products is a real problem. How do you keep the information organised, referenced, accessible and useful ?
This three part screencast is about how I manage all the “inputs” so I don’t feel lost in information after many, many people asked.
I’ve been thinking about the security issues of working with Huawei equipment and Huawei the company. I’ve spoken with a number of people who, off the record, talk of working with Huawei as customers and their experiences of the product have been less than excellent but the price is low. What I’ve realised is concerning. […]
Arista has announced the 7150S device. It’s low latency, 10 Gigabit and VXLAN terminating. What’s interesting to me is that Brocade and Arista are solving the same problem in different ways. Ivan has determined that Arista have decided to use the Intel chipset (I’m guessing the SM6000?) and then enable the tunnel termination features in the software.
I attended the Brocade Analyst and Tech Day last week as a guest of Brocade where I got to learn more about product, technology and strategy. In particular, the event was led by the launch of the Brocade VDX 8770.
TL:DR version: I have a better understanding of Brocade’s market strategy, insight into the technology and believe that Brocade has a a good product here. The proof will be in the delivery, and whether Brocade can let go of it’s storage legacy (FibreChannel) and properly commit to Ethernet. They will need to convince networking professionals that their product managers understand the market and requirements to get them to switch to Brocade. At this time, I think Brocade has a chance of making that happen based on the emphasis of VCS Fabric and Automation.
Where I’m less comfortable is that Brocade will rely on external parties to deliver the software automation – that’s a strategy that has NOT worked in the last 20 years. There is no reason to believe this anything has changed.
Contains pictures and words.
Have been receiving email with questions on OpenFlow/SDN and looking for a definition blog post that explains how East/West and North/South LAN design can work with Northbound/Southbound APIs
Short version – I’d like you to read just these if nothing else.
- A data centre uses a lot of electricity. It’s dangerous.
- Just in case you didn’t pay attention – Electricity is really dangerous. Right, can we move on ?
- You should be scared of being electrocuted. That will keep you safe.
- When electrocution happens, the muscles in your limbs contract. This causes arms and hands to wrap around or clench objects.
- Someone who is being electrocuted can’t let go because of this
- If you touch a person being electrocuted, you will get an electric shock too, and may also be injured.
- The BEST thing to do is to turn the power off.
- Know where the power kill switch is for Data Centre. Or at least the breaker for the area that you are in.
- Don’t work in the Data Centre alone.
- Learn resuscitation. People who have been electrocuted are likely to have breathing problems and heart failure.
People shouldn’t die at work. Think seriously about going home everyday and what you can do to make that happen.
There is an old saying “A man with his eyes fixed on Heaven doesn’t see where he is going”. It’s an almost perfect description of how the major vendors are bringing Software Defined Networking to the market.
The consistent message from all the vendors and especially the Cisco, Juniper and Brocade is that there are “no use cases for SDN”. In the last three months, this has been a constantly repeated statement both publicly and privately. This beggars belief that vendors can’t see immediate needs that deliver long term gains.
I suspect that the root of this problem is the big companies want to solve big problems. And by solving big problems they figure that they can make big revenue. Alright, I get that. It’s understandable that large organisations need a constant revenue stream to feed the insatiable maws of their shareholders. However, the vendors re also missing the most real and immediate problem of networking today. Simply, Networking is too hard.
Vendors haven’t developed tools that keep the complexity of networking under control. Complexity can be reduced to this: “I don’t have big problems, I have lots of small problems.” You can have debates about addressing complexity and how to attack it, but it nearly always boils down to this: start small.
In November 2011, I posted “What Are 10 Gigabit Ultra Short Reach (USR) Optics ?” where I tried to what is the actual difference between these Ultra Short Reach (USR) optics and the certified 10Gbase-SR products. I recently received the following from an anonymous source. I’ve made some small edits to protect identity and improve the text.
In this post, I’m looking at network designs with ECMP cores using TRILL or SPB, I’m realising that STP is equally improved in terms of risk and performance by reducing the STP domain size which leads to better stability, reduced risk and impact mitigation
A lot of people have talked extensively about OpenFlow making significant changes to the networking business. In particular, many writers have focussed on the possibility that OpenFlow enables a choice of using low cost network equipment instead of the expensive networking equipment that we use today.
Well, that’s highly unlikely.
I don’t use a Cloud for any of my blogs or email services. I’ve looked at three different cloud providers including Amazon, Rackspace and others. I guessed that they all would work, more or less. Except they cost between four to ten times the solution from a managed service provider. Here is my exit report for the fictitious consulting engagement with myself.