Many real time applications such as VOIP, gaming, teleconferencing, and performing music together, require low latency. These are increasingly unusable in today’s internet, and not because there is insufficient bandwidth, but that we’ve failed to look at the Internet as a end to end system. The edge of the Internet now often runs congested. When it does, bufferbloat causes performance to fall off a cliff.
Where once a home user’s Internet connection consisted of a single computer, it now consists of a dozen or more devices – smart phones, TV’s, Apple TV’s/Roku devices, tablet devices, home security equipment, and one or more computer per household member. More Internet connected devices are arriving every year, which often perform background activities without user’s intervention, inducing transients on the network. These devices need to effectively share the edge connection, in order to make each user happy. All can induce congestion and bufferbloat that baffle most Internet users.
The CoDel (“coddle”) AQM algorithm provides the “missing link” necessary for good TCP behavior and solving bufferbloat. But CoDel by itself is insufficient to solve provide reliable, predictable low latency performance in today’s Internet.
Bottlenecks are most common at the “edge” of the Internet and there you must Continue reading
That was it! My work life has an absolute peak every year and that’s when I’m again fortunate enough to visit Cisco Live in the US. This year it was held in San Diego, California.
I flew in on Saturday with 2 colleagues on LA and drove to San Diego after a quick tour around Sunset Boulevard ;)
We stayed at the Manchester Grand Hyatt, which is a hotel I can truly recommend when visiting San Diego. Services were good and staff was helpful!
My focus this year was to combine both Datacenter and Service Provider sessions as those are the fields I’m active in. I found that the SP related sessions had a quite smaller crowd attending them. I guess this is related as the SP customers are considered important customers and get a lot more attention from Cisco people, so they already know what to expect in terms of roadmap and technologies. Still I had quite some very good sessions where I learnt about the features (and limitations) about some cool new things :-)
Sunday
On Sunday it’s a special day as you need to purchase additional sessions called Techtorials. This was the first year I took a Continue reading
The CCIE Datacenter techtorial was a very good session giving a good overview about the contents of the exam. I will not focus on the technologies in this article, but only on the specifics that I wrote down during the session. This means you will only find details about the exam and not about the technologies.
There are enough resources to find details about the technologies, but you are reading this article if you want to know what to find when you step into the testing center or the lab.
The session was presented by 3 guys, I would specifically mention Walid Issa who is the product manager for this particular CCIE track. Walid is a very nice guy and if you want to know something about the lab, ask him!
Written
Over 200 took the written beta already. it’s expected that a lot more people will take the DC written beta during Cisco live San Diego.
The Written is an overview of technologies with a medium to hard level. As all other written exams for CCIE the focus is on theory and not on configuration. When you know the technologies you should be able to pass.
Lab
Sample topology Continue reading
Why do we need to do this? What’s wrong with today’s network?
Anyone who has deployed or managed a large PIM multicast environment will relate to the response to this question. PIM works on the assumption of an overlay protocol model. PIM stands for Protocol Independent Multicast, which means that it can utilize any IP routing table to establish a reverse path forwarding tree. These routes can be created with any independent unicast routing protocol such as RIP or OSPF, or even be static routes or combinations thereof. In essence, there is an overlay of the different protocols to establish a pseudo-state within the network for the forwarding of multicast data. As any network engineer who has worked with large PIM deployments will attest, they are sensitive beasts that do not lend themselves well to topology changes or expansions of the network delivery system. The key word in all of this is the term ‘state’. If it is lost, then the tree truncates and the distribution service for that length of the tree is effectively lost. Consequently, changes need to be done carefully and be well tested and planned. And this is all due to the fact that the Continue reading
Last time I ran any kind of flash/java based speedtest was back in Feb. when I was still on my tunnel and behind a DOCSIS 2.x modem:
Decided that I needed to re-run the test now that I’m both behind a DOCSIS 3.x modem, and have native IPv6 from Comcast:
After the success of last year’s World IPv6 Day, where success was measured with little to no problems reported, World IPv6 Launch Day has arrived! For a while major players like Google and Facebook had been white-listing their AAAA records to specific ISP recursive nameservers. This meant you had to query one of those in order to see IPv6 entries for their websites. Now that white-listing has been removed and all properly operating recursive nameservers will now serve up these records. They aren’t the only companies participating of course! Take a look at this list to see whom else signed up to promote their enabling of IPv6. Want some stats, take a look at the following:
But what does this mean to the non-techies out there? It is meant to be a passive change. You shouldn’t notice much in the way of interruptions. Perhaps your ISP will have a shorter route to a destination over IPv6, and you might get what you are trying to access a tiny bit quicker. If you like video/chat applications, this will soon mean that you’ll be Continue reading